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MP 8.01.49 Intensity Modulated Radiation Therapy (IMRT) - Abdomen and Pelvis

Medical Policy    
Section
Therapy
Original Policy Date
04/2009
Last Review Status/Date
Reviewed with literature search/12:2012
Issue
12:2012
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Disclaimer

Our medical policies are designed for informational purposes only and are not an authorization, or an explanation of benefits, or a contract.  Receipt of benefits is subject to satisfaction of all terms and conditions of the coverage.  Medical technology is constantly changing, and we reserve the right to review and update our policies periodically.


Description

Radiation therapy may be an integral component in the treatment of cancers of the abdomen and pelvis. Intensity-modulated radiation therapy (IMRT) has been proposed as a method of radiation therapy that allows adequate radiation therapy to the tumor while minimizing the radiation dose to surrounding normal tissues and critical structures.

Radiation techniques

Conventional external-beam radiation therapy. Over the past several decades, methods to plan and deliver radiation therapy have evolved in ways that permit more precise targeting of tumors with complex geometries. Most early trials used 2-dimensional treatment planning, based on flat images and radiation beams with cross-sections of uniform intensity that were sequentially aimed at the tumor along 2 or 3 intersecting axes. Collectively, these methods are termed “conventional external-beam radiation therapy.”

3-dimensional conformal radiation (3D-CRT). Treatment planning evolved by using 3-dimensional images, usually from computed tomography (CT) scans, to delineate the boundaries of the tumor and discriminate tumor tissue from adjacent normal tissue and nearby organs at risk for radiation damage. Computer algorithms were developed to estimate cumulative radiation dose delivered to each volume of interest by summing the contribution from each shaped beam. Methods also were developed to position the patient and the radiation portal reproducibly for each fraction and immobilize the patient, thus maintaining consistent beam axes across treatment sessions. Collectively, these methods are termed 3-dimensional conformal radiation therapy (3D-CRT).

Intensity-modulated radiation therapy (IMRT). IMRT, which uses computer software, CT images, and magnetic resonance imaging (MRI), offers better conformality than 3D-CRT as it is able to modulate the intensity of the overlapping radiation beams projected on the target and to use multiple-shaped treatment fields. It uses a device (a multileaf collimator, MLC) which, coupled to a computer algorithm, allows for “inverse” treatment planning. The radiation oncologist delineates the target on each slice of a CT scan and specifies the target’s prescribed radiation dose, acceptable limits of dose heterogeneity within the target volume, adjacent normal tissue volumes to avoid, and acceptable dose limits within the normal tissues. Based on these parameters and a digitally reconstructed radiographic image of the tumor and surrounding tissues and organs at risk, computer software optimizes the location, shape, and intensities of the beams ports to achieve the treatment plan’s goals.

Increased conformality may permit escalated tumor doses without increasing normal tissue toxicity and thus may improve local tumor control, with decreased exposure to surrounding normal tissues, potentially reducing acute and late radiation toxicities. Better dose homogeneity within the target may also improve local tumor control by avoiding underdosing within the tumor and may decrease toxicity by avoiding overdosing.

Since most tumors move as patients breathe, dosimetry with stationary targets may not accurately reflect doses delivered within target volumes and adjacent tissues in patients. Furthermore, treatment planning and delivery are more complex, time-consuming, and labor-intensive for IMRT than for 3D-CRT. Thus, clinical studies must test whether IMRT improves tumor control or reduces acute and late toxicities when compared with 3D-CRT.

Methodologic issues with IMRT studies

Multiple-dose planning studies have generated 3D-CRT and IMRT treatment plans from the same scans, then compared predicted dose distributions within the target and in adjacent organs at risk. Results of such planning studies show that IMRT improves on 3D-CRT with respect to conformality to, and dose homogeneity within, the target. Dosimetry using stationary targets generally confirms these predictions. Thus, radiation oncologists hypothesized that IMRT may improve treatment outcomes compared with those of 3D-CRT. However, these types of studies offer indirect evidence on treatment benefit from IMRT, and it is difficult to relate results of dosing studies to actual effects on health outcomes.

Comparative studies of radiation-induced side effects from IMRT versus alternative radiation delivery are probably the most important type of evidence in establishing the benefit of IMRT. Such studies would answer the question of whether the theoretical benefit of IMRT in sparing normal tissue translates into real health outcomes. Single-arm series of IMRT can give some insights into the potential for benefit, particularly if an adverse effect that is expected to occur at high rates is shown to decrease by a large amount. Studies of treatment benefit are also important to establish that IMRT is at least as good as other types of delivery, but in the absence of such comparative trials, it is likely that benefit from IMRT is at least as good as with other types of delivery.

Note: Evidence for the following abdominal and pelvic cancers has not yet been reviewed and is beyond the scope of this current policy: bladder cancer, esophageal cancer, and sarcoma.


Policy

Intensity-modulated radiation therapy may be considered medically necessary as an approach to delivering radiation therapy for patients with cancer of the anus/anal canal.

When dosimetric planning with standard 3-D conformal radiation predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity (see Policy Guidelines), intensity-modulated radiation therapy (IMRT) may be considered medically necessary for the treatment of cancer of the abdomen and pelvis, including but not limited to:

  • stomach (gastric);
  • hepatobiliary tract;
  • pancreas;
  • rectal locations; or
  • gynecologic tumors (including cervical, endometrial, and vulvar cancers).

Intensity-modulated radiation therapy (IMRT) would be considered investigational for all other uses in the abdomen and pelvis.


Policy Guidelines

Radiation tolerance doses for normal tissues of the abdomen and pelvis

 

TD 5/5 (Gy)a

 

TD 50/5 (Gy)b

 
 
 

Portion of organ involved

 

Portion of organ involved

 
 

Site

 

1/3

 

2/3

 

3/3

 

1/3

 

2/3

 

3/3

 

Complication endpoint

 

Heart

 
60   45   40   70   55   50   Pericarditis  

Lung

 
45   30   17.5   65   40   24.5   Pneumonitis  

Spinal cord

 
50   50   47   70   70   NP   Myelitis/necrosis  

Kidney

 
50   30   23   NP   40   28   Clinical nephritis  

Liver

 
50   35   30   55   45   40   Liver failure  

Stomach

 
60   55   50   70   67   65   Ulceration/perforation  

Small intestine

 
50   NP   40   60   NP   55   Obstruction/perforation  

Femoral head

 
NP   NP   52   NP   NP   65   Necrosis  

aTD 5/5, the average dose that results in a 5% complication risk within 5 years

bTD 50/5, the average dose that results in a 50% complication risk within 5 years

NP: not provided

The tolerance doses in the table are a compilation from the following two sources:

Morgan MA (2011). Radiation Oncology. In DeVita, Lawrence and Rosenberg, Cancer (p.308). Philadelphia: Lippincott Williams and Wilkins.

Kehwar TS, Sharma SC. Use of normal tissue tolerance doses into linear quadratic equation to estimate normal tissue complication probability. http://www.rooj.com/Radiation%20Tissue%20Tolerance.htm

In order for IMRT to provide outcomes that are superior to 3DCRT, there must be a clinically meaningful decrease in the radiation exposure to normal structures with IMRT compared to 3DCRT. There is not a standardized definition for a clinically meaningful decrease in radiation dose. In principle, a clinically meaningful decrease would signify a significant reduction in anticipated complications of radiation exposure. In order to document a clinically meaningful reduction in dose, dosimetry planning studies should demonstrate a significant decrease in the maximum dose of radiation delivered per unit of tissue, and/or a significant decrease in the volume of normal tissue exposed to potentially toxic radiation doses. While radiation tolerance dose levels for normal tissues are well-established, the decrease in the volume of tissue exposed that is needed to provide a clinically meaningful benefit has not been standardized. Therefore, precise parameters for a clinically meaningful decrease cannot be provided.

The following CPT codes specifically describe intensity-modulated radiation therapy (IMRT):

77301: Intensity-modulated radiotherapy plan, including dose-volume histograms for target and critical structure partial tolerance specification.

77418: Intensity-modulated treatment delivery, single or multiple fields/arcs, via narrow spatially and temporally modulated beams, binary, dynamic MLC, per treatment session.

0073T: Compensator-based beam modulation treatment delivery of inverse planned treatment using three or more high resolution (milled or cast) compensator convergent beam modulated fields, per treatment session.

Effective in 2010, a new code was added:

77338: Multi-leaf collimator (MLC) device(s) for intensity modulated radiation therapy (IMRT), design and construction per IMRT plan.

Code 77338 is to be reported only once per IMRT plan and should not be reported with 0073T.


Benefit Application

BlueCard/National Account Issues

State or federal mandates (e.g., FEP) may dictate that all devices approved by the U.S. Food and Drug Administration (FDA) may not be considered investigational, and thus these devices may be assessed only on the basis of their medical necessity.


Rationale

Introduction

Methods to plan and deliver intensity-modulated radiation therapy (IMRT) methods are not uniform.(1-3) IMRT may use beams that remain on as the multileaf collimator (MLC) moves around the patient (dynamic MLC), or that are turned off during movement and turned on when the MLC reaches prespecified positions (“step and shoot” technique). A third alternative uses a very narrow single beam that moves spirally around the patient (tomotherapy). Each of these methods uses different computer algorithms to plan treatment and yields somewhat different dose distributions in and outside the target. Patient position can alter target shape and thus affect treatment plans. IMRT may be delivered with the patient in the prone or supine position. However, data are unavailable to compare clinical outcomes for patients treated in prone versus supine positions, and consensus is lacking. Respiratory motion of the internal organs during radiation treatments is another concern when using IMRT to treat lesions in those compartments. Treatment plans are usually based on one imaging scan, a static 3-dimensional computed tomography (CT) image. They partially compensate for day-to-day (inter-fraction) variability in patient set-up, and for (intrafraction) motion of the target and organs at risk, by expanding the target volume with uniform margins around the tumor (generally 0.5–1 cm for all positional uncertainty).

Current methods seek to reduce positional uncertainty for tumors and adjacent normal tissues by various techniques. Patient immobilization cradles and skin or bony markers are used to minimize day-to-day variability in patient positioning. An active breathing control device combined with moderately deep inspiration breath-holding techniques may be used to improve conformality and dose distributions during IMRT. Other techniques being studied with internal tumors include gate beam delivery to the patient’s respiratory movement or continuous monitor of tumor (by in-room imaging) or marker (internal or surface) positions to aim radiation more accurately at the target. The impact of these techniques on outcomes of IMRT for any cancer is unknown. However, it appears likely that respiratory motion alters the dose distributions actually delivered while treating patients from those predicted by plans based on static CT scans, or measured by dosimetry, using stationary (non-breathing) targets. In addition, many tumors have irregular edges that preclude drawing tight margins on CT scan slices when radiation oncologists contour the tumor volume. It is unknown whether omitting some tumor cells or including some normal cells in the resulting target affects outcomes of IMRT. Finally, tumor size may change over the course of treatment as tumors respond or progress, which has potential effects on radiation dose delivery and distribution. Whether outcomes might be improved by repeating scans and modifying treatment plans accordingly (termed adaptive radiation therapy) is unknown.

The Advanced Technology Consortium (ATC) has helped to develop general guidelines for protocols that incorporate IMRT as an option. These guidelines were communicated to all clinical trial groups by the National Cancer Institute (NCI) and clearly stated that respiratory motion could cause far more problems for IMRT than for traditional radiotherapy treatments (ATC Guidelines for use of IMRT for intra-thoracic treatments).

These considerations emphasize the need to compare clinical outcomes rather than treatment plan predictions to determine whether one radiotherapy method is superior to another.

Technology Assessments and Systematic Reviews

Two reviews summarized evidence on the use of IMRT for a number of cancers, including head and neck, prostate, gynecologic, breast, lung, and gastrointestinal.(4,5) The authors presented the reviews as analysis of comparative clinical studies; in reality, they categorized several small case series using historical cohorts as controls as comparative studies for several tumor types. This method limits the value of the reviews in assessing the role of IMRT for the diseases addressed in this policy.

Primary Literature

Literature searches have identified no studies that directly compare health outcomes with IMRT versus those in patients treated concurrently with any other type of radiotherapy for tumors of the thorax (e.g., esophagus), upper abdomen (e.g., stomach, pancreas, bile duct, liver), or pelvis (e.g., rectal, anal, gynecologic). Case series and single-arm studies of IMRT have been identified, including some with historical controls treated with non-IMRT methods.

Gastrointestinal Tract

Stomach

As outlined in a recent review article, IMRT has been investigated for treatment of gastric cancer in several studies, but only one reported clinical outcomes.(1) In a small (n=7) case series, patients with stage III gastric cancer received postoperative chemoradiotherapy with 5-fluorouracil (5FU) and leucovorin and IMRT delivered to a dose of 50.4 Gy in 1.8 Gy fractions.(6) Chemoradiotherapy with IMRT was well-tolerated, with no acute gastrointestinal (GI) tract toxicities (nausea, diarrhea, esophagitis) greater than grade 2.

The efficacy and safety of 2 different adjuvant chemoradiotherapy regimens using 3-dimensional conformal radiation (3D-CRT) (n=27) or IMRT (n=33) were evaluated in 2 consecutive cohorts of patients who underwent primarily D2 resection for gastric cancer.(7) The cohorts in this study were generally well-matched, with American Joint Committee on Cancer (AJCC) advanced stage (II-IV) disease. The majority (n=26, 96%) of those who received 3D-CRT were treated with 5-fluorouracil plus folinic acid (5FU/FA); the other patient received oxaliplatin plus capecitabine (XELOX). In the 3D-CRT cohort, 13 (50%) patients completed the 5FU/FA regimen, 13 halted early because of acute toxicity or progression and received a median 60% of planned cycles. Patients in the IMRT cohort received XELOX (n=23, 70%) or 5FU/FA (n=10, 30%). Five of 10 (50%) patients completed all planned 5FU/FA cycles, the other 5 received only a median 60% of cycles because of acute toxicity. Thirteen (56%) treated with XELOX completed all planned cycles; the other 10 received a median of 70% planned cycles because of toxicity. Radiation was delivered to a total prescribed dose of 45 Gy/1.8 Gy/fraction in 21 (81%) of the 3D-CRT cohort patients; 5 received less than 45 Gy because of intolerance to treatment. Thirty (91%) patients in the IMRT cohort received the planned 45 Gy dosage; 2 (6%) were unable to tolerate the full course, and 1 case planned for 50.4 Gy was halted at 47 Gy. The median overall survival (OS) was 18 months in the 3D-CRT cohort, and more than 70 months in the IMRT cohort (p=0.0492). The actuarial 2-year OS rates were 67% in the IMRT cohort and 37% in the 3D-CRT group (p not reported). Acute renal toxicity based on creatinine levels was generally lower in the IMRT cohort compared to the 3D-CRT group, with a significant difference observed at 6 weeks (p=0.0210). In the 3D-CRT group, LENT-SOMA grade 2 renal toxicity was observed in 2 patients (8%) whereas no grade 2 toxicity was reported in the IMRT group.

Hepatobiliary

In a retrospective series with a historical control cohort, clinical results achieved with image-guided IMRT (n=24) were compared to results with CRT (n=24) in patients with primary adenocarcinoma of the biliary tract.(8) The majority of patients underwent postsurgical chemoradiotherapy with concurrent fluoropyrimidine-based regimens. IMRT treatment plans prescribed 46 to 56 Gy to the planning target volume (PTV) that includes the tumor and involved lymph nodes, in daily fractions of 1.8–2 Gy. CRT involved 3-D planning that delivered 46–50 Gy in 1.8–2 Gy daily fractions. Both groups received boost doses of 4–18 Gy as needed. The median estimated overall survival (OS) for all patients who completed treatment was 13.9 months (range: 9.0–17.6); the IMRT cohort had median OS of 17.6 months (range: 10.3–32.3), while the CRT cohort had a median OS of 9.0 months (range: 6.6–17.3). Acute GI toxicities were mild to moderate, with no significant differences between patient cohorts. These results suggest that moderate dose escalation via conformal radiotherapy is technically and clinically feasible for treatment of biliary tract adenocarcinoma. However, while this series represents the largest group of patients with this disease treated with IMRT, generalization of its results is limited by the small numbers of patients, use of retrospective chart-review data, nonrepresentative case spectrum (mostly advanced/metastatic disease), and comparison to a nonconcurrent control radiotherapy cohort.

Two single arm studies reported outcomes with IMRT in patients with hepatobiliary cancers. The first study involved 42 patients with advanced (33% AJCC stage IIIC, 67% stage IV) hepatocellular carcinoma (HCC) with multiple extrahepatic metastases.(9) Among the 42 cases, 33 (79%) had intrahepatic HCC with extrahepatic metastases, 9 (21%) had only extrahepatic lesions. The extrahepatic locations of HCC metastatic lesions included lung (n=19), lymph node and adrenal (n=20), other soft tissues (n=6), and bone (n=5). Helical tomotherapy was performed simultaneously for all lesions in each patient, with a total radiation dose of 50 and 40 Gy to 95% of the gross tumor volume (GTV) and PTV in 10 fractions divided over 2 weeks. All received capecitabine during the course of IMRT as a radiosensitizer. After completion of tomotherapy, additional transarterial or systemic chemotherapy was administered to patients eligible for it according to tumor location. Among 31 patients who underwent hepatic IMRT, a mean of 3 courses (range: 1-6) transarterial chemolipiodolization was performed in 23. Among 9 patients with extrahepatic lesions only, 3 received an additional 3-7 cycles of systemic chemotherapy consisting of epirubicin, cisplatin, and 5FU. Median follow-up was 9.4 months (range: 1.9–25.3 months). Tumor response was reported separately for each organ treated with IMRT. The overall objective tumor response rate was 45% for intrahepatic HCC, 68% for pulmonary lesions, 60% for lymph node and adrenal cases, and 67% for soft tissue metastases. Three cases of local tumor progression occurred within the target radiation area, including 2 intrahepatic HCC and 1 abdominal lymph node metastasis. Median OS was 12.3 months, with 15% OS at 24 months. The most common acute adverse events were mild anorexia and constitutional symptoms that occurred 1-2 weeks after start of IMRT, regressed spontaneously or subsided with symptomatic care, and did not interfere with the scheduled delivery of IMRT. However, it is not possible to discern the impact of IMRT on adverse events because almost all occurred in patients who received chemotherapy following IMRT. However, most patients were reported to have tolerated therapy well, with no treatment-related mortality.

A second retrospective single-arm study involved 20 patients with primary, unresectable HCC who were treated with IMRT and concurrent capecitabine.(10) Patients had AJCC grade T1 (n = 7) and T3 (n = 13) HCC. IMRT was prescribed to a minimum tumor dose of 50 Gy in 20 fractions over 4 weeks, with the optimization goal of delivering the prescription dose to 95% of the PTV. Capecitabine was administered as radiosensitizer on the days of IMRT delivery. Eleven (55%) patients underwent at least 1 transarterial chemoembolization (range: 1-3 procedures) before radiotherapy planning. Eighteen of 20 (90%) patients completed the full course of IMRT, 2 died before follow-up imaging was obtained. The mean survival of 18 patients who completed IMRT was 9.6 months after its conclusion. Disease progression occurred in-field in 3 patients, 2 failed elsewhere in the liver. Four patients (25%) required hospitalization during therapy, due to encephalopathy (n=1), gastric ulcer (n=1), acute hepatitis (n=1), and sepsis (n=1). Four required a break from chemotherapy because of peripheral neuropathy (n=2), acute hepatitis (n=1), and sepsis (n=1). Grade 1 acute abdominal pain was observed in 15%, 30% reported grade 1 nausea, 5% experienced grade 2 nausea. No acute or late toxicity greater than grade 2 was reported.

Pancreatic

Three reports of case series provide clinical results with IMRT for pancreatic carcinoma. The largest series involved a retrospective analysis of 41 patients who received image-guided IMRT alone, postsurgically (41%), or with a number of concurrent primarily fluoropyrimidine-based chemotherapy regimens (88%).(11) The prescribed radiation dose to the PTV ranged from 41.4–60.4 Gy in daily fractions of 1.8–2 Gy. For all patients diagnosed with adenocarcinoma (85%), 1- and 2-year actuarial OS were 38% and 25%, respectively; median OS in resected patients was 10.8 months (range: 6.2–55.1), as compared to 10.0 months (range: 3.4–28.0) in inoperable cases. Four patients (9.7%) were unable to complete radiotherapy as prescribed. Any upper GI acute toxicity (none grade 4) was reported in 29 (70%) patients, most commonly nausea, vomiting, and abdominal pain; any lower GI acute toxicity (less than 5% grade 4) was reported in 17 (42%) cases, primarily diarrhea.

In a second series of 25 patients with pancreatic and bile duct cancers (68% unresectable), 24 were treated with IMRT and concurrent 5FU, 1 refused chemotherapy.(12) Resected patients received 45–50.4 Gy to the PTV, whereas unresectable patients received 50.4–59.4 Gy. For all cancers, the median OS was 13.4 months, with 1- and 2-year OS of 55% and 22%, respectively. One- and 2-year median OS were 83% and 50%, respectively, among resected cases, and 40% and 8%, respectively, among unresected cases. IMRT was well-tolerated, with grade 2 or less acute upper GI toxicity in 80% of patients; grade 4 late liver toxicity was reported in 1 patient who survived more than 5 years.

A third retrospective series included 15 patients with pancreatic adenocarcinoma (7 resected, 8 unresectable) who underwent IMRT plus concurrent capecitabine.(13) Resected cases received 45–54 Gy to the gross tumor volume, unresected cases received 54–55 Gy to the gross tumor volume; all cases received 45 Gy to the draining lymph node basin. At a median follow-up of 8.5 months, no deaths were reported among the resected patients, compared to 2 deaths in the unresected cases, yielding a 1-year OS rate of 69% among the latter. No grade 4 toxicities were reported, with the vast majority of acute toxicities reported at grade 1 (nausea, vomiting, diarrhea, neutropenia, anemia).

Gynecologic

A series of reports from a single institution provided data on clinical outcomes achieved with IMRT in women with gynecologic malignancies. Patients from an initial series(14) were included in a subsequent report that comprised 40 patients who underwent IMRT to treat cancers of the cervix, endometrium, and other sites (3 patients).(15) Patients in this series underwent postsurgical IMRT (70%), with (58%) or without (42%) cisplatin chemotherapy, with a majority (60%) also undergoing postradiotherapy intracavitary brachytherapy (ICB). IMRT was prescribed to the PTV at a dose of 45 Gy, delivered in 1.8 Gy daily fractions; ICB delivered an additional 30–40 Gy to cervical cancer patients and 20–25 Gy to those with endometrial cancer. A well-matched nonconcurrent cohort of patients who underwent 4-field CRT (45 Gy to the PTV, 1.8 Gy daily fractions) using 3D planning and received cisplatin chemotherapy was used to compare acute GI and genitourinary (GU) toxicities between radiotherapy modalities. No grade 3 acute GI or GU toxicities were reported in IMRT or CRT recipients. Grade 2 GI toxicity was noted in 60% of the IMRT cohort versus 91% of the CRT group (p=0.002). No significant differences were noted in the incidence of grade 2 GU toxicity in IMRT recipients (10%) compared to the CRT cohort (20%). Three other reports from the same group provide data on acute hematologic toxicity,(16) chronic GI toxicities, (17) and acute GI toxicities(18) among patients who underwent IMRT with or without chemotherapy. It is unclear whether or not the patients in these reports are those from the initial studies or are new patients.

A small case series involved 10 patients who underwent IMRT with intracavitary brachytherapy boost for locally advanced (FIGO stage IIB and IIIB) cervical cancer.(19) During radiotherapy, all patients received cisplatin. Whole pelvic IMRT was administered to a dose of 50.4 Gy in 28 fractions, and intracavitary brachytherapy (ICB) was delivered to a dose of 30 Gy in 6 fractions. The mean OS was 25 months (range: 3-27 months), with actuarial OS of 67%. Acute toxicities included 1 patient with grade 3 diarrhea, 1 with grade 3 thrombocytopenia, and 3 with grade 3 leukopenia. One case of subacute grade 3 thrombocytopenia was noted. These data are insufficient to draw conclusions about the efficacy or safety of IMRT in cervical cancer.

Two subsequent studies examined the use of post-hysterectomy radiotherapy in women with high-risk cervical cancer. In the first study, 68 patients were treated with adjuvant pelvic radiotherapy, high dose-rate ICB, and concurrent chemotherapy.(20) The initial 35 cases received 4-field box CRT delivered to the whole pelvis; a subsequent 33 patients underwent IMRT. All patients received 50.4 Gy of radiation in 28 fractions and 6 Gy of high dose-rate vaginal cuff ICB in 3 insertions; cisplatin was administered concurrently to all patients. All patients completed the planned course of treatment. At median follow-up of 34.6 months (range: 12–52) in CRT recipients and 14 months (range: 6–25) in IMRT recipients, the 1-year locoregional control rate was 94% for CRT and 93% for IMRT. Grades 1 to 2 acute GI toxicities were noted in 36% and 80% of IMRT and CRT recipients, respectively (p=0.00012), while acute grade 1 to 2 GU toxicities occurred in 30% versus 60%, respectively (p=0.022). There was no significant difference between IMRT and CRT in the incidence of acute hematologic toxicities. Overall, the IMRT patients had lower rates of chronic GI (p=0.002) toxicities than the CRT patients.

A subsequent report from the same group included the initial 33 patients in that experience with an additional 21 cases.(21) At a median follow-up of 20 months, this study showed a 3-year disease-free survival rate of 78% and an OS rate of 98% in IMRT recipients.

Anorectal

A single-institution series included 17 patients with stage I/II cancer who underwent IMRT alone (n=3) or concurrent with 5FU alone (n=1) or 5FU with mitomycin C (MMC, n=13).(22) Patients generally received 45 Gy to the PTV at 1.8 Gy per fraction, followed by a 9 Gy boost to the gross tumor volume. Thirteen of 17 (76%) patients completed treatment as planned. None experienced acute or late grade 3 or above nonhematologic (GI or GU) toxicity. Grade 4 acute hematologic toxicity (leukopenia, neutropenia, thrombocytopenia) was reported in 5 of 13 (38%) patients who received concurrent chemoradiotherapy. At a median follow-up of 20.3 months, the 2-year OS rate was 91%.

A multicenter series included a cohort of 53 consecutive patients who received concurrent chemotherapy and IMRT.(23) Forty-eight (91%) received 5FU plus MMC, the rest received other regimens not including MMC. Radiation was delivered at 45 Gy to the PTV. Thirty-one (58%) patients completed therapy as planned, with breaks in the others because of grade 4 hematologic toxicities (40% of patients), painful moist desquamation, or severe GI toxicities. At the18-month follow-up, the local tumor control rate was 83.9% (range: 69.9–91.6%), with an OS rate of 93.4% (range: 80.6–97.8%). Univariate analyses did not reveal any factors significantly associated with tumor control or survival rates, whereas a multivariate analysis showed patients with stage IIIB disease experienced a significantly lower colostomy-free survival (hazard ratio 4.18; 95% CI: 1.062–16.417; p=0.041).

A gastrointestinal toxicity study was reported in 45 patients who received concurrent chemotherapy and IMRT for anal cancer.(24) Chemoradiotherapy is becoming the standard treatment for anal cancer, in part due to preservation of sphincter function. Patients had T1 (n=1), T2 (n=24), T3 (n=16), and T4 (n=2) tumors; N stages included Nx (n=1), N0 (n=31), N1 (n=8), N2 (n=3), and N3 (n=2). Concurrent chemotherapy primarily comprised 5-FU plus mitomycin C (MMC). IMRT was administered to a dose of 45 Gy in 1.8 Gy fractions, with areas of gross disease subsequently boosted with 9–14.4 Gy. Acute genitourinary toxicity was grade 0 in 25 (56%) cases, grade 1 in 10 (22%) patients, grade 2 in 5 (11%) patients, with no grade 3 or 4 toxicities reported; 5 (11%) patients had no genitourinary tract toxicities reported. Grades 3-4 leukopenia was reported in 26 (56%) cases, neutropenia in 14 (31%), and anemia in 4 (9%). Acute GI toxicity included grade 0 in 2 (4%) patients, grade 1 in 11 (24%), grade 2A in 25 (56%), grade 2B in 4 (9%), grade 3 in 3 (7%) and no grade 4 toxicities. Univariate analysis of data from these patients suggests a statistical correlation between the volume of bowel that received 30 Gy or more of radiation and the risk for clinically significant (grade 2 or higher) GI toxicities.

A retrospective analysis of toxicity and disease outcomes associated with IMRT was performed in 47 patients with anal cancer.(25) Thirty-one patients had squamous cell carcinoma (SCC). Patients had AJCC stage I (n=6, 13%), stage II (n=16, 36%), stage III (n=14, 31%), stage IV (n=6, 13%), or recurrent disease (n=3, 7%). IMRT was prescribed to a dose of at least 54 Gy to areas of gross disease at 1.8 Gy per fraction. Forty patients (89%) received concurrent chemotherapy with a variety of agents including MMC, 5FU, capecitabine, oxaliplatin, etoposide, vincristine, doxorubicin, cyclophosphamide, and ifosfamide in various combinations. The 2-year actuarial OS for all patients was 85%. Eight patients (18%) required treatment breaks. Toxicities included grade 4 leukopenia (7%) and thrombocytopenia (2%); grade 3 leukopenia (18%) and anemia (4%); and, grade 2 skin (93%). These rates were much lower than previous trials of chemoradiation, where grade 3 to 4 skin toxicity was noted in about 50% of patients and grade 3 to 4 GI toxicity noted in about 35%. In addition, the rate of treatment breaks was lower than in many studies; and some studies of chemoradiation include a break from radiation therapy. Some investigators believe that treatment breaks reduce the efficacy of this combined approach. .

A small (n=6) case series of IMRT and concurrent infusional 5FU plus cisplatin was reported in patients with anal cancer and para-aortic nodal involvement.(26) IMRT was delivered to a median dose of 57.5 Gy to the CTV, with nodal areas of involvement treated to a median dose of 55 Gy. Five of 6 completed the entire prescribed course of IMRT. The 3-year actuarial OS rate was 63%. Four patients developed grade 3 acute toxicities that included nausea and vomiting, diarrhea, dehydration, small bowel obstruction, neutropenia, anemia, and leukopenia. Five of 6 had grade 2 skin toxicity.

Input from Academic Medical Centers and Physician Specialty Societies

In response to requests, input was received from one physician specialty society (4 reviewers) and 3 academic medical centers while this policy was under review for August 2012. While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted. The input was somewhat mixed, but there was support for use of IMRT in a number of cancers discussed above. In general, this support was based on finding different radiation doses to various organs based on treatment planning studies. There was some support for the use of IMRT when currently accepted normal dose constraints for safe delivery of radiation therapy could not be met without using IMRT.

In response to requests, input was received from one physician specialty society (2 reviewers) and 3 academic medical centers while this policy was under review for May 2010. While the various physician specialty societies and academic medical centers may collaborate with and make recommendations during this process through the provision of appropriate reviewers, input received does not represent an endorsement or position statement by the physician specialty societies or academic medical centers, unless otherwise noted. There was support for use of IMRT in a number of cancers discussed above. In general, this support was based on finding different radiation doses to various organs based on treatment planning studies.

Clinicaltrials.govDatabase

More than two dozen Phase II or III clinical trials are recruiting patients to evaluate the use of IMRT in gynecologic, pancreatic, colorectal, and hepatobiliary tract cancer (available online at: http://clinicaltrials.gov/ct2/results?term=imrt&recr=Open&rslt=&type=Intr&cond=anal+OR+anorectal+OR+pelvic+OR+pancreatic+OR+gastric+OR+hepatobiliary+OR+vulval+OR+endometrial+OR+uterine+OR+cervical&intr=&outc=&spons=&lead=&id=&state1=&cntry1=&state2=&cntry2=&state3=&cntry3=&locn=&gndr=&phase=1&phase=2&rcv_s=&rcv_e=&lup_s=&lup_e=).

Guidelines and Position Statements

National Comprehensive Cancer Network (NCCN) Guidelines

The guidelines for anal carcinoma (http://www.nccn.org/professionals/physician_gls/PDF/anal.pdf, V.1.2013) state that IMRT “may be used in place of 3D conformal RT in the treatment of anal carcinoma;” and, that “Its use requires expertise and careful application to avoid reduction in local control probability.”

The guidelines also indicate that IMRT remains investigational for gastric cancer (http://www.nccn.org/professionals/physician_gls/pdf/gastric.pdf, V.2.2012). However, according to the NCCN, “IMRT may be appropriate in selected cases to reduce dose to normal structures such as heart, lungs, kidneys and liver. In designing IMRT plans for structures such as the lungs, attention should be given to the volume receiving low to moderate doses, as well as the volume receiving high doses.”

In cervical cancer (http://www.nccn.org/professionals/physician_gls/PDF/cervical.pdf, V.1.2012), the guidelines mention that IMRT is “becoming more widely used” but issues with reproducibility, immobilization and definition of target “remain to be validated.”

Although IMRT is mentioned as an option in the guidelines for pancreatic adenocarcinoma, they indicate a lack of consensus on radiotherapy dose and appropriate setting for use of IMRT in this disease. (http://www.nccn.org/professionals/physician_gls/PDF/pancreatic.pdf, V.2.2012).

IMRT is not mentioned in the guidelines for hepatobiliary cancers. (http://www.nccn.org/professionals/physician_gls/PDF/hepatobiliary.pdf, V.2.2012).

IMRT is not mentioned in the guidelines for uterine endometrial cancer. (http://www.nccn.org/professionals/physician_gls/PDF/uterine.pdf, V.3.2012).

Summary

The body of evidence available to assess the role of intensity-modulated radiation therapy (IMRT) in the treatment of cancers of the abdomen and pelvis generally comprises case series, both retrospective and prospective. No randomized trials have been reported that compare results with IMRT to any other conformal radiation therapy (CRT), nor do any of the case series include concurrently treated control patients. The available results are generally viewed as hypothesis-generating for the design and execution of comparative trials of IMRT versus CRT that evaluate tumor control and survival outcomes in the context of adverse events and safety.

The comparative data on use of IMRT versus 3-dimensional conformal radiation (3D-CRT) in chemoradiotherapy for anal cancer shows marked differences in rates of acute toxicity. Thus, use of IMRT in cancer of the anus/anal canal may be considered medically necessary.

For other tumors of the abdomen and pelvis, the evidence from treatment planning studies has shown that the use of IMRT decreases radiation doses delivered to normal tissue adjacent to tumor. This potentially lowers the risk of adverse events (acute and late effects of radiation toxicity), although the clinical benefit of reducing the radiation dose to normal tissue using IMRT is theoretical. Due to the limitations in this evidence, this policy underwent clinical vetting. There was support for the use of IMRT in tumors of the abdomen and pelvis when normal tissues would receive unacceptable doses of radiation. The results of the vetting, together with an indirect chain of evidence and the potential to reduce harms, led to the decision that IMRT may be considered medically necessary for the treatment of tumors of the abdomen and pelvis when dosimetric planning with standard 3-D conformal radiation predicts that the radiation dose to an adjacent organ would result in unacceptable normal tissue toxicity.

 References:

    1. Meyer JJ, Czito BG, Willett CG. Intensity-modulated radiation therapy for gastrointestinal tumors. Curr Oncol Rep 2008; 10(3):206-11.
    2. Randall ME, Ibbott GS. Intensity-modulated radiation therapy for gynecologic cancers: pitfalls, hazards, and cautions to be considered. Semin Radiat Oncol 2006; 16(3):138-43.
    3. Taylor A, Powell ME. Conformal and intensity-modulated radiotherapy for cervical cancer. Clin Oncol (R Coll Radiol) 2008; 20(6):417-25.
    4. Staffurth J. A review of the clinical evidence for intensity-modulated radiotherapy. Clin Oncol (R Coll Radiol) 2010; 22(8):643-57.
    5. Veldeman L, Madani I, Hulstaert F et al. Evidence behind use of intensity-modulated radiotherapy: a systematic review of comparative clinical studies. Lancet Oncol 2008; 9(4):367-75.
    6. Milano MT, Garofalo MC, Chmura SJ et al. Intensity-modulated radiation therapy in the treatment of gastric cancer: early clinical outcome and dosimetric comparison with conventional techniques. Br J Radiol 2006; 79(942):497-503.
    7. Boda-Heggemann J, Hofheinz RD, Weiss C et al. Combined adjuvant radiochemotherapy with IMRT/XELOX improves outcome with low renal toxicity in gastric cancer. Int J Radiat Oncol Biol Phys 2009; 75(4):1187-95.
    8. Fuller CD, Dang ND, Wang SJ et al. Image-guided intensity-modulated radiotherapy (IG-IMRT) for biliary adenocarcinomas: Initial clinical results. Radiother Oncol 2009; 92(2):249-54.
    9. Jang JW, Kay CS, You CR et al. Simultaneous multitarget irradiation using helical tomotherapy for advanced hepatocellular carcinoma with multiple extrahepatic metastases. Int J Radiat Oncol Biol Phys 2009; 74(2):412-8.
    10. McIntosh A, Hagspiel KD, Al-Osaimi AM et al. Accelerated treatment using intensity-modulated radiation therapy plus concurrent capecitabine for unresectable hepatocellular carcinoma. Cancer 2009; 115(21):5117-25.
    11. Fuss M, Wong A, Fuller CD et al. Image-guided intensity-modulated radiotherapy for pancreatic carcinoma. Gastrointest Cancer Res 2007; 1(1):2-11.
    12. Milano MT, Chmura SJ, Garofalo MC et al. Intensity-modulated radiotherapy in treatment of pancreatic and bile duct malignancies: toxicity and clinical outcome. Int J Radiat Oncol Biol Phys 2004; 59(2):445-53.
    13. Ben-Josef E, Shields AF, Vaishampayan U et al. Intensity-modulated radiotherapy (IMRT) and concurrent capecitabine for pancreatic cancer. Int J Radiat Oncol Biol Phys 2004; 59(2):454-9.
    14. Mundt AJ, Roeske JC, Lujan AE et al. Initial clinical experience with intensity-modulated whole-pelvis radiation therapy in women with gynecologic malignancies. Gynecol Oncol 2001; 82(3):456-63.
    15. Mundt AJ, Lujan AE, Rotmensch J et al. Intensity-modulated whole pelvic radiotherapy in women with gynecologic malignancies. Int J Radiat Oncol Biol Phys 2002; 52(5):1330-7.
    16. Brixey CJ, Roeske JC, Lujan AE et al. Impact of intensity-modulated radiotherapy on acute hematologic toxicity in women with gynecologic malignancies. Int J Radiat Oncol Biol Phys 2002; 54(5):1388-96.
    17. Mundt AJ, Mell LK, Roeske JC. Preliminary analysis of chronic gastrointestinal toxicity in gynecology patients treated with intensity-modulated whole pelvic radiation therapy. Int J Radiat Oncol Biol Phys 2003; 56(5):1354-60.
    18. Roeske JC, Bonta D, Mell LK et al. A dosimetric analysis of acute gastrointestinal toxicity in women receiving intensity-modulated whole-pelvic radiation therapy. Radiother Oncol 2003; 69(2):201-7.
    19. Hsieh CH, Wei MC, Lee HY et al. Whole pelvic helical tomotherapy for locally advanced cervical cancer: technical implementation of IMRT with helical tomotherapy. Radiat Oncol 2009; 4:62.
    20. Chen MF, Tseng CJ, Tseng CC et al. Clinical outcome in posthysterectomy cervical cancer patients treated with concurrent Cisplatin and intensity-modulated pelvic radiotherapy: comparison with conventional radiotherapy. Int J Radiat Oncol Biol Phys 2007; 67(5):1438-44.
    21. Chen MF, Tseng CJ, Tseng CC et al. Adjuvant concurrent chemoradiotherapy with intensity-modulated pelvic radiotherapy after surgery for high-risk, early stage cervical cancer patients. Cancer J 2008; 14(3):200-6.
    22. Milano MT, Jani AB, Farrey KJ et al. Intensity-modulated radiation therapy (IMRT) in the treatment of anal cancer: toxicity and clinical outcome. Int J Radiat Oncol Biol Phys 2005; 63(2):354-61.
    23. Salama JK, Mell LK, Schomas DA et al. Concurrent chemotherapy and intensity-modulated radiation therapy for anal canal cancer patients: a multicenter experience. J Clin Oncol 2007; 25(29):4581-6.
    24. Devisetty K, Mell LK, Salama JK et al. A multi-institutional acute gastrointestinal toxicity analysis of anal cancer patients treated with concurrent intensity-modulated radiation therapy (IMRT) and chemotherapy. Radiother Oncol 2009; 93(2):298-301.
    25. Pepek JM, Willett CG, Wu QJ et al. Intensity-modulated radiation therapy for anal malignancies: a preliminary toxicity and disease outcomes analysis. Int J Radiat Oncol Biol Phys 2010; 78(5):1413-9.
    26. Hodges JC, Das P, Eng C et al. Intensity-modulated radiation therapy for the treatment of squamous cell anal cancer with para-aortic nodal involvement. Int J Radiat Oncol Biol Phys 2009; 75(3):791-4.
     

Codes

Number

Description

CPT  77301 Intensity modulated radiotherapy plan, including dose volume histograms for target and critical structure partial tolerance specification
  77338 Design and construction of a multi-leaf collimator for use in intensity modulated radiation therapy (IMRT) (new code 1/01/10)
  77418 Intensity modulated treatment delivery, single or multiple fields/arcs, via narrow spatially and temporally modulated beams, binary dynamic multileaf collimator, per treatment session
  0073T Compensator-based beam modulation treatment delivery of inverse planned treatment using three or more high resolution compensator convergent beam modulated fields, per treatment session
ICD-9-CM Diagnosis 151.0-151.9 Malignant neoplasm of stomach, code range
  152.0-152.9 Malignant neoplasm of small intestine code range
  153.0-153.9 Malignant neoplasm of colon code range
  154.0-154.8 Malignant neoplasm of rectum, rectosigmoid junction and anus code range (154.2 and 154.3 are specific to the anal canal and anus, unspecified)
  155.0-155.2 Malignant neoplasm of liver and intrahepatic bile ducts code range
  156.0-156.9 Malignant neoplasm of gallbaldder and extrahepatic bile ducts code range
  157.0-157.9 Malignant neoplasm of pancrease code range
  158.0-158.9 Malignant neoplasm of retroperioneum and peritoneum code range
  159.0-159.9 Malignant neoplasm of other and ill-definied sites within the digestive organs and peritoneum code range
  179 Malignant neoplasm of uterus, part unspecified
  180.0-180.9 Malignant neoplasm of cervix uteri code range
  182.0-182.8

Malignant neoplasm of body of uterus code range

  183.0-183.9 Malignant neoplasm of ovary and othe ruterin adnexa code range
  184.0-184.9 Malignant neoplasm of other and unspecified female genital organs code range
ICD-10-CM (effective 10/1/14) C16.0-C16.9 Malignant neoplasm of stomach, code range
  C17.0-C17.9 Malignant neoplasm of small inestine code range
  C18.0-C18.9 Malignant neoplasm of other and unspecidied female gential organs code range
  C19 Malignant neoplasm of sigmoid junction
  C20 Malignant neoplasm of rectum
  C21.0-C21.8 Malignant neoplams of anus, code range
  C22.0-C22.9 Malignant neoplams of live and intrahepatic bile ducts code range
  C23 Malignant neoplasm of the gallbladder
  C24.0-C24.9 Malignant neoplasm of other and unspecified parts of biliary tract code range
  C25.0-C25.9 Malignant neoplasm of pancrease code range
  C26.0-C26.9 Malignant neoplasm of other and ill-definied sites within th edigestive organs and peritoneum code range
  C51.0-C51.9 Malignant neoplasm of vulva code range
  C52 Malignant neoplasm of vagina
  C53.0-C53.9 Malignant neoplasm of cervix uteri code range
  C54.0-C54.9 Malignant neoplasm of corpus uteri code range
  C55 Malignant neoplasm of uterus part unspecified
  C56.1-C56.9 Malignant neoplasm of ovary and other uterine adnexa code range
  C57.00-C57.9 Malignant neoplasm of other and unspecified female genital organs code range
ICD-10-PCS (effective 10/1/14)   ICD-10-PCS codes are only used of inpatient services. There is no specific ICD-10_PCS code for this imaging.


Index

IMRT, abdomen
IMRT, pelvis


Policy History

Date Action Reason
04/24/09 Add to Therapy section Policy created with literature search through March 2009; considered investigational
12/29/09 Coding update only add 77338
05/13/10 update policy Policy updated with literature search; reference numbers 19-25 added; clinical input reviewed; policy statement revised to indicate use in anal cancers may be considered medically necessary
12/13/12 Replace Policy Policy updated with literature search; no new references added. Policy statement changed to state that IMRT may be considered medically necessary for all anal cancers (not limited to squamous cell carcinoma). Policy statement changed to state that IMRT may be considered medically necessary for the treatment of tumors of the abdomen and pelvis when dosimetric planning predicts the volume of small intestine receiving doses >45 Gy with standard 3-D conformal radiation would result in unacceptable risk of small intestine injury. Added a policy statement that IMRT would be considered investigational for all other uses in the abdomen and pelvis. Paragraph added to policy guidelines regarding toxic radiation dose to tissues and definition of a clinically significant decrease in radiation dose.