|MP 6.01.51||PET Scanning in Oncology to Detect Early Response during Treatment|
|Original Policy Date
|Last Review Status/Date
Reviewed with literature search/8:2013
|Return to Medical Policy Index|
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.
Positron emission tomography (PET) scan has many established roles in oncology. Another potential use of PET scanning is early in the course of treatment to assess treatment response, with the intent of altering therapy if the PET scan shows inadequate response.
Positron emission tomography (PET) scans are based on the use of positron emitting radionuclide tracers coupled to other molecules, such as glucose, ammonia, or water. The radionuclide tracers simultaneously emit 2 high-energy photons in opposite directions that can be simultaneously detected (referred to as coincidence detection) by a PET scanner, consisting of multiple stationary detectors that encircle the area of interest.
A variety of tracers are used for PET scanning, including oxygen-15, nitrogen-13, carbon-11, and fluorine-18. The radiotracer most commonly used in oncology imaging has been fluorine-18, coupled with fluorodeoxyglucose (FDG), which has a metabolism related to glucose metabolism. FDG has been considered potentially useful in cancer imaging, since tumor cells show increased metabolism of glucose. This policy focuses on a specific indication for an oncologic application of PET scanning.
This policy focuses on the use of PET to determine early treatment response for cancer, that is, assessment of therapy response during cancer treatment. The purpose of the PET scan at this particular interval is to determine whether the treatment being given should be maintained or changed. Such a treatment strategy has been called “risk-adapted” or “response-adapted” treatment. This policy addresses detecting early response during short-term therapy, e.g., during cycle(s) of chemotherapeutic agents and/or a course of radiation therapy, and not on assessing response during use of long-term agents, such as tamoxifen.
This use is to be distinguished from all uses of PET in the initial diagnosis and staging of cancer and other uses after treatment, such as routine surveillance or detection of recurrence. This is also different from what has been called “response assessment” or “treatment response” in some reports but clearly refers to imaging done after completion of therapy for the purpose of prognosis and future treatment planning. Some reports differentiate between PET during treatment and PET after treatment by referring to PET during cancer treatment as “interim treatment response” or “interim staging” and PET at the conclusion of treatment as “restaging.”
The technique of using PET for early treatment response assessment involves comparing PET images before treatment and at some interval after the initial course of treatment. Many intervals have been used in various studies, and there appears to be no standard interval. Comparison of the pre-treatment and mid-treatment PET images can either be performed qualitatively or quantitatively. If a quantitative technique is used, a quantity called the standardized uptake value (SUV) is calculated for a specific region of the image. Various methods are used to compare the SUV between the 2 images, and a specific cut-off value is selected to determine whether the patient is responding or not responding to therapy. A change in SUV between 40% and 60% has often been used in studies of early treatment response.Related Policies:
6.01.06 Miscellaneous Applications of Positron Emission Tomography (PET)
6.01.20 Cardiac Applications of PET Scanning
6.01.26 Oncologic Applications of PET Scanning
The use of positron emission tomography (PET) scans to determine early response to treatment (PET scans done during a planned course of chemotherapy and/or radiation therapy) in patients with cancer is considered investigational.
There is no specific coding for positron emission tomography (PET) scans to determine early response to treatment. The CPT codes for PET or PET/computed tomography (CT) imaging (78811-78816) would be used.
Effective in July 2009, there is a HCPCS modifier created by Medicare that might be helpful:
Modifier PS: Positron emission tomography (PET) or PET/computed tomography (CT) to inform the subsequent treatment strategy of cancerous tumors when the beneficiary’s treating physician determines that the PET study is needed to inform subsequent anti-tumor strategy.
BlueCard/National Account Issues
This policy was created in April 2009 and updated periodically with literature review. The most recent update with literature review covers the period of June 2012 through July 2013.
The use of positron emission tomography (PET) during treatment to detect early treatment response and as a trigger to potentially change treatment at that time makes this imaging procedure more closely tied to treatment than is usually the case with diagnostic tests, and thus, risk-adapted treatment using PET could be evaluated in randomized clinical trials (RCTs). However, no such clinical trials have been completed, although at least 11 studies have been described in clinical trial registries. (1-11) Most of these registered RCTs address Hodgkin and non-Hodgkin lymphomas, although one trial includes patients with adenocarcinoma of the esophagus and gastroesophageal junction. Published case series, in which outcomes are reported for patients whose treatment has been directed by interim PET scans, appear to be rare. A comprehensive review of PET published by the National Health Service (NHS) in the United Kingdom in 2007 specifically looked for but did not find any studies reporting outcomes of patients whose treatment had been altered by interim PET. (12) However, according to a study generated from the National Oncologic PET Registry, which collected data on PET scans to develop evidence for Medicare coverage policy, PET is often used during treatment to change therapy, most often to a different therapy when the PET scan indicates progressive disease. (13) No patient outcomes were reported in this study, however.
The lack of studies showing impact on clinical outcomes based on PET-directed treatment makes it difficult to determine whether using PET during treatment will result in improved patient outcomes. Most studies that evaluate PET during treatment have analyzed PET in relation to various findings such as pathologic or clinical response at the end of treatment, PET at the end of treatment, or long-term results. Although associations between PET and all these findings have consistently been found for a number of cancers, whether such associations can lead directly to improved patient outcomes depends on the specific context of the treatment being used and the alternatives available. For example, if PET during treatment is highly specific for non-response to chemotherapy, and the alternative treatment for non-response is withdrawal of therapy, then treatment-directed PET could lead to withdrawal of ineffective treatment (and its adverse effects) for a subset of patients. If the alternative treatment is a different chemotherapeutic agent, then outcomes would be improved only if the alternative agent results in better outcomes. Use of PET during treatment may not improve outcomes compared to a PET performed after treatment or more than using a different method of response assessment. Interim PET could possibly simply advance the timing of alternative therapies, producing a lead-time bias effect without actually improving outcomes.
Other types of treatment protocols using PET-directed treatment that could potentially improve patient outcomes are possible. For example, treatment with less toxic agents that are less efficacious could be tried initially and changed quickly if PET showed that the initial agents were ineffective; thus allowing that subset of patients for whom a treatment is working to be treated successfully with less toxic treatment.
Evaluation of these types of treatment protocols would seem to require direct evidence from clinical trials, and conclusions about efficacy could not follow directly from current observational studies of PET. The following sections summarize the literature on PET during treatment for several major cancers in which its use has been proposed or is apparently being used.
A 2007 National Comprehensive Cancer Network (NCCN) Task Force report on PET scanning in cancer makes no specific recommendation, but the language seems to indicate that the benefits of PET during treatment are not proven. (14) “Study results suggest that therapy does not need to be changed when the PET scan is negative, but a separate trial is needed to determine whether a positive PET scan should prompt an alternative therapy and whether this alternative therapy can improve outcomes.” A consensus statement released in 2007 by the Imaging Subcommittee of the International Harmonization Project in Lymphoma stated that use of PET for treatment monitoring during a course of therapy should only be done in a clinical trial or as part of a prospective registry. (15) This statement also comments on the need for clinical trials to demonstrate improved patient outcomes. The document otherwise proposes a strong endorsement for PET at the conclusion of therapy.
A comprehensive review of PET for lymphoma by the British National Health Service (NHS) identified 9 studies evaluating PET during treatment. (12) PET during treatment was highly associated with either patient survival or progression, such that patients who had positive PET scans during treatment were more likely to have progressed or have shorter survival. The 9 studies reviewed all had fewer than 100 patients, and different methods were used to analyze the PET scans. Cut-off values to differentiate a positive from a negative PET scan were invariably derived post hoc, possibly leading to an overestimate of discriminative capability.
In a case series of risk-adapted treatment using mid-treatment PET to alter therapy in lymphoma, 33 of 59 patients with positive mid-treatment PET scans had therapy changed to more aggressive therapy with platinum-based salvage chemotherapy, high-dose therapy, and autologous stem-cell transplantation. (16)These patients had a 2-year event-free survival of 67%, which is better than is historically associated with such patients who have positive mid-treatment PET scans. However, such case series data are not definitive in establishing the benefit of such a treatment strategy.
Some single-arm studies that assess outcomes of patients receiving treatment changes based on interim PET/CT (computed tomography) scans suggest that some chemotherapeutic regimens can be intensified or switched to less-toxic regimens without harm. (17, 18) The conclusions of single-arm studies may be biased by selection and lead-time bias. Imperfect prediction of poor prognosis may lead to some low-risk patients being classified as high risk, improving the group’s survival. Earlier treatment using salvage therapies may result in a lead-time bias, which would also give an apparent survival improvement. Given the potential for selection and lead-time biases, comparative trials would be necessary to determine the efficacy of such a strategy.
In the 2013 update of the NCCN guidelines on Hodgkin lymphoma, several statements were made regarding use of interim PET. (19) Initial studies suggested that for early stage Hodgkin lymphoma (stage I to II favorable disease), interim PET imaging was not considered to be of important prognostic significance. However, the guideline cites two prospective 2012 studies by Kostakaglu et al. and Zinzani et al. that found that PET scans after 2 cycles of chemotherapy were significant predictors of progression-free survival. (20, 21) For more advanced disease, interim PET imaging predicts long-term outcomes. Although interim PET has prognostic capability, the document states that “guiding therapy based on the results of interim PET imaging is considered investigational and is not recommended outside the context of a clinical trial.” However, if interim PET imaging is to be performed in patients with stage I to II unfavorable (bulky or nonbulky) disease or stage III to IV disease, it may be performed after 2 to 4 cycles of chemotherapy. Interim staging with diagnostic CT was recommended for certain patients receiving certain treatment regimens. For non-Hodgkin lymphoma, the most recent 2013 NCCN guidelines do not support interim PET for altering treatment. (22)
The NCCN Task Force report discusses studies examining the role of PET in determining early treatment response for non-small-cell lung cancer but makes no statement recommending such use. (14) Three studies were cited that showed that interim PET scans during neoadjuvant therapy were associated with pathologic findings at surgery or with median time to cancer progression.
No studies were identified that evaluated the outcomes of patients whose treatments were altered with mid-treatment PET. The British NHS review identified several studies that evaluated use of PET for post-treatment assessment and only one study that evaluated PET during treatment. (12) In that study, PET findings during chemotherapy were associated with clinical measures of best response evaluated at the end of therapy with a sensitivity of 95% and a specificity of 74%. Other studies have shown an association between PET and overall survival in patients. However, early prediction of survival does not translate to patient benefit unless the decisions that were based on those predictions can result in improved patient outcomes by either extending survival or improving quality of life.
Ovarian cancer was the most common type of cancer in which PET was used during treatment in the National Oncologic PET registry. (13) Neither the NCCN Task Force nor the British NHS review included ovarian cancer among the uses of PET considered in their reports. (12, 14)
There were no case series or comparative trials of risk-adapted treatment for ovarian cancer identified. One study evaluates the use of PET during chemotherapy to predict patient outcomes in 33 patients, without making management changes. (23) Using various thresholds of change in standardized uptake value (SUV), median survival was worse among those who had less of a change in SUV. For example, at a threshold of decrease in SUV of 20% after the first cycle of chemotherapy, overall survival was 38.3 months in responders and 23.1 months in nonresponders. Clinical response, CA-125 response, and histopathologic response did not correlate with overall survival. Although PET during treatment appears to be associated with response and may be better than other methods of prognosis, whether such improved prediction leads to improved patient outcomes is not demonstrated in this type of study.
Other cancers were assessed for PET during treatment in the NCCN Task Force Report. (14) The report cites 1 small study of colorectal cancer patients showing an association between PET and tumor response to 5-fluorouracil after 1 month of therapy. They concluded in their summary recommendation that PET scans are not routinely indicated to monitor response to chemotherapy or radiation therapy. The report cited several studies of breast cancer patients and early PET and commented on promising data but included this indication among several other uses in breast cancer that are in need of further research.
Other cancers were also assessed for PET during treatment in the British NHS review. (12) The report identified a prior systematic review and 3 other primary studies that demonstrated associations between PET during treatment and responses in breast cancer. No studies showing outcomes of PET-directed treatment for breast cancer were identified. For colorectal cancer, 1 study was identified that showed that PET after 1 month of chemotherapy predicted outcome, but the predictive accuracy was rather low. For head and neck cancer, esophageal cancer, and melanoma, only studies that evaluated PET performed after treatments were identified.
Including sections of this report summarized in other sections of this policy, the British NHS review found 22 studies of PET during treatment. They conclude that many of the studies were small, evaluating different treatments, with a diversity of response targets and monitoring methods. There was little evidence of change in patient management, even anecdotally, and no published evidence of successful applications to drug development.
Clinical Input Received through Physician Specialty Societies and Academic Medical Centers
In response to requests, input was received from one physician specialty society and 5 academic medical centers while this policy was under review in 2011. 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. In general, there was agreement with the conclusions of this policy from those providing input. Most of the disagreement related to use of PET scans during a planned course of treatment for patients with Hodgkin lymphoma. Some reviewers felt current data were sufficient to show benefit, others commented that additional studies needed to evaluate this issue.
There is a lack of high-quality literature on the use of positron emission tomography (PET) scans in various cancers to determine early response to treatment. These scans may provide some additional information on risk prediction and/or prognosis, but the effect of these scans on the net health outcome is not known. Comparative trials would be necessary to determine if health outcomes are improved based on treatment changes instituted based on early PET scans. Therefore, PET scanning done during a planned course of cancer treatment for the purpose of altering the treatment plan is considered investigational.
Practice Guidelines and Position Statements
A 2007 National Comprehensive Cancer Network (NCCN) Task Force report on PET scanning in cancer makes no specific recommendation, but the language seems to indicate that the benefits of PET during treatment are not proven. (14) “Study results suggest that therapy does not need to be changed when the PET scan is negative, but a separate trial is needed to determine whether a positive PET scan should prompt an alternative therapy and whether this alternative therapy can improve outcomes.” A consensus statement released in 2007 by the Imaging Subcommittee of the International Harmonization Project in Lymphoma stated that use of PET for treatment monitoring during a course of therapy should only be done in a clinical trial or as part of a prospective registry. (15) This statement also comments on the need for clinical trials to demonstrate improved patient outcomes. The document otherwise proposes a strong endorsement for PET at the conclusion of therapy.References:
- Gruppo Italiano Terapie Innovative nei Linfomi (GITIL). Multicentre clinical study with early treatment intensification in patients with high-risk Hodgkin Lymphoma, identified as 18-F Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) scan positive after two conventional Doxorubicin, Bleomycin, Vinblastine, Dacarbazine (ABVD) courses. Available online at: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=83276. Last accessed July 2013.
- Australasian Gastro-Intestinal Trials Group (AGITG). A Randomised Phase II Trial of Pre-operative cisplatin, 5 fluorouracil and docetaxel ± Radiotherapy based on poor early response to standard chemotherapy for resectable adenocarcinoma of the oesophagus and/or OG Junction. Available online at: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=308313. Last accessed July 2013.
- University of Cologne. HD18 for Advanced Stages in Hodgkins Lymphoma. Available online at: http://clinicaltrials.gov/ct2/show/NCT00515554. Last accessed July 2013.
- Ospedale Santa Croce-Carle Cuneo. Positron Emission Tomography (PET)-Adapted Chemotherapy In Advanced Hodgkin Lymphoma (HL) (HD0607). Available online at: http://clinicaltrials.gov/ct2/show/NCT00795613. Last accessed July 2013.
- European Organisation for Research and Treatment of Cancer (EORTC). Fludeoxyglucose F 18 PET Scan-Guided Therapy or Standard Therapy in Treating Patients With Previously Untreated Stage I or Stage II Hodgkin's Lymphoma. Available online at: http://clinicaltrials.gov/ct2/show/record/NCT00433433. Last accessed July 2013.
- European Organisation for Research and Treatment of Cancer (EORTC). Very Early FDG-PET/CT-response Adapted Therapy for Advanced Hodgkin Lymphoma (H11). Available online at: http://clinicaltrials.gov/ct2/show/NCT01652261. Last accessed July 2013.
- Fondazione Italiana Linfomi (ONLUS). High-dose Chemotherapy and Stem Cell Transplantation, in Patients PET-2 Positive, After 2 Courses of ABVD and Comparison of RT Versus no RT in PET-2 Negative Patients (HD0801). Available online at: http://clinicaltrials.gov/ct2/show/NCT00784537. Last accessed July 2013.
- The Lymphoma Academic Research Organisation. Study Evaluating the Non-inferiority of a Treatment Adapted to the Early Response Evaluated With 18FFDG PET Compared to a Standard Treatment, for Patients Aged From 18 to 80 Years With Low Risk (aa IPI = 0) Diffuse Large B-cells Non Hodgkin's Lymphoma CD 20+. Available online at: http://clinicaltrials.gov/ct2/show/NCT01285765. Last accessed July 2013.
- Cancer Research UK. Fludeoxyglucose F 18-PET/CT Imaging in Assessing Response to Chemotherapy in Patients With Newly Diagnosed Stage II, Stage III, or Stage IV Hodgkin Lymphoma. Available online at: http://clinicaltrials.gov/ct2/show/NCT00678327. Last accessed July 2013.
- University College, London. PET Scan in Planning Treatment in Patients Undergoing Combination Chemotherapy For Stage IA or Stage IIA Hodgkin Lymphoma (RAPID). Available online at: http://clinicaltrials.gov/ct2/show/NCT00943423. Last accessed July 2013.
- University Hospital Essen. Positron Emission Tomography Guided Therapy of Aggressive Non-Hodgkin's Lymphomas (PETAL). Available online at: http://clinicaltrials.gov/ct2/show/NCT00554164. Last accessed July 2013.
- Facey K, Bradbury I, Laking G et al. Overview of the clinical effectiveness of positron emission tomography imaging in selected cancers. Health Technol Assess 2007; 11(44):iii-iv, xi-267.
- Hillner BE, Siegel BA, Shields AF et al. The impact of positron emission tomography (PET) on expected management during cancer treatment: findings of the National Oncologic PET Registry. Cancer 2009; 115(2):410-8.
- Podoloff DA, Advani RH, Allred C et al. NCCN task force report: positron emission tomography (PET)/computed tomography (CT) scanning in cancer. J Natl Compr Canc Netw 2007; 5(suppl 1):S1-22.
- Juweid ME, Stroobants S, Hoekstra OS et al. Use of positron emission tomography for response assessment of lymphoma: consensus of the Imaging Subcommittee of International Harmonization Project in Lymphoma. J Clin Oncol 2007; 25(5):571-8.
- Kasamon YL, Wahl RL, Ziessman HA et al. Phase II study of risk-adapted therapy of newly diagnosed, aggressive non-Hodgkin lymphoma based on midtreatment FDG-PET scanning. Biol Blood Marrow Transplant 2009; 15(2):242-8.
- Dann EJ, Bar-Shalom R, Tamir A et al. Risk-adapted BEACOPP regimen can reduce the cumulative dose of chemotherapy for standard and high-risk Hodgkin lymphoma with no impairment of outcome. Blood 2007; 109(3):905-9.
- Dann EJ, Blumenfeld Z, Bar-Shalom R et al. A 10-year experience with treatment of high and standard risk Hodgkin disease: six cycles of tailored BEACOPP, with interim scintigraphy, are effective and female fertility is preserved. Am J Hematol 2012; 87(1):32-6.
- National Comprehensive Cancer Network. Clinical Practice Guidelines in Oncology. Hodgkin Lymphoma (V2.2013). Available online at: http://www.nccn.org/professionals/physician_gls/pdf/hodgkins.pdf. Last accessed July 2013.
- Kostakoglu L, Schoder H, Johnson JL et al. Interim [(18)F]fluorodeoxyglucose positron emission tomography imaging in stage I-II non-bulky Hodgkin lymphoma: would using combined positron emission tomography and computed tomography criteria better predict response than each test alone? Leuk Lymphoma 2012; 53(11):2143-50.
- Zinzani PL, Rigacci L, Stefoni V et al. Early interim 18F-FDG PET in Hodgkin's lymphoma: evaluation on 304 patients. Eur J Nucl Med Mol Imaging 2012; 39(1):4-12.
- National Comprehensive Cancer Network. Clinical Practice Guidelines in Oncology. Non-Hodgkin's Lymphomas (V.1.2013). Available online at: http://www.nccn.org/professionals/physician_gls/pdf/nhl.pdf. Last accessed July 2013.
- Avril N, Sassen S, Schmalfeldt B et al. Prediction of response to neoadjuvant chemotherapy by sequential F-18-fluorodeoxyglucose positron emission tomography in patients with advanced-stage ovarian cancer. J Clin Oncol 2005; 23(30):7445-53.
|CPT||78811, 78812, 78813||Positron emission tomography (PET) imaging, coding range|
|78814, 78815, 78816||Positron emission tomography (PET) with concurrently acquired computed tomography (CT) for attenuation correction and anatomical localization imaging, coding range|
|ICD-9 Diagnosis||Investigational for all diagnoses when used to determine early response to treatment.|
|HCPCS||Modifier - PS||Positron emission tomography (PET) or PET/computed tomography (CT) to inform the subsequent treatment strategy of cancerous tumors when the beneficiary’s treating physician determines that the PET study is needed to inform subsequent anti-tumor strategy (effective 7/1/09)|
|ICD-10-CM (effective 10/1/14)||Investigational for all diagnoses when used to determine early response to treatment.|
|C00.0-C14.8||Malignant neoplasm of lip, oral cavity and pharynx code range|
|C15.3-C15.9||Malignant neoplasm of esophagus code range|
|C18.0-C18.9||Malignant neoplasm of colon code range|
|C19||Malignant neoplasm of rectosigmoid junction (includes colon with rectum)|
|C25.0-C25.9||Malignant neoplasm of pancreas code range|
|C30.0-C31.9||Malignant neoplasm of nasal cavities, middle ear and accessory sinuses code range|
|C32.0-C32.9||Malignant neoplasm of larynx code range|
|C34.0-C34.92||Malignant neoplasm of bronchus and lung code range|
|C43.0-C43.9||Malignant melanoma of skin code range|
|C50.011-C50.929||Malignant neoplasm of breast code range|
|C53.0-C53.9||Malignant neoplasm of cervix uteri code range|
|C56.0-C56.9||Malignant neoplasm of ovary code range|
|C62.00-C62.92||Malignant neoplasm of testis code range|
|C73||Malignant neoplasm of thyroid gland|
|C76.0||Malignant neoplasm of head, face and neck NOS|
|C80.0-C80.1||Malignant neoplasm without specification of site (unknown primary)|
|C81.00-C81.99||Hodgkin’s disease code range|
|C82.00-C88.9||Other malignant neoplasm of lymphoid tissue (other lymphomas)|
|ICD-10-PCS (effective 10/1/14)||ICD-10-PCS is for use only on inpatient services. There are a few specific PET ICD-10-PCS codes such as the following:|
|CB32KZZ, CB32YZZ||Nuclear medicine, respiratory system, positron emission tomographic (PET) imaging, lungs and bronchi, code by radionuclide|
|CB3YYZZ||Nuclear medicine, respiratory system, positron emission tomographic (PET) imaging, respiratory system|
|04/24/09||Add to Radiology section||Policy created with literature search through April 2009;
considered investigational when performed to determine early response to treatment.
|12/09/10||Replace policy||Policy updated with literature search; references 9 and 10 added. No change to policy statement|
|5/12/11||Replace policy||Policy updated with review of clinical input. No change in policy statement|
|08/09/12||Replace policy||Policy updated with literature review, reference 9 deleted, reference 10 added. No change in policy statement.|
|8/08/13||Replace policy||Policy updated with literature review through July 2013; reference 1 deleted, references 2 through 11, 20, and 21 added. Old reference 11 replaced with new reference 19. No change in policy statement.|