Prophylactic mastectomy is defined as the removal of the breast in the absence of malignant disease. Prophylactic mastectomies may be considered in women considered at high risk of developing breast cancer, either due to a family history, presence of a BRCA1 or BRCA2 mutation, or the presence of lesions associated with an increased cancer risk. Such lesions include atypical hyperplasia and lobular carcinoma in situ (LCIS). Although LCIS is labeled as a cancer, it is thought not to have invasive potential, but patients with LCIS are at increased risk of developing an invasive breast cancer elsewhere in either breast. Therefore, bilateral prophylactic mastectomy is performed not to excise the LCIS lesion itself, but to eliminate the risk of cancer arising elsewhere. Prophylactic mastectomies are typically bilateral, but can also describe a unilateral mastectomy in a patient who has previously undergone a mastectomy in the opposite breast for an invasive cancer.

Two types of prophylactic mastectomies can be performed; either total (also referred to as simple) mastectomy, in which the intent is to remove the entire breast and nipple areolar complex, and subcutaneous mastectomy, in which the nipple areolar complex is left intact for a more natural appearance. While breast tissue is certainly left behind in a subcutaneous mastectomy, residual breast tissue in the axillary tail and skin flaps may be identified after a total mastectomy. However, from a purely prophylactic standpoint, a total mastectomy is generally preferred over a subcutaneous mastectomy because there is less residual breast tissue.

The appropriateness of a prophylactic mastectomy is a complicated risk-benefit analysis that requires estimates of a patient’s risk of breast cancer, typically based on the patient’s family history of breast cancer and other factors. Two models are most frequently used, the Claus model and the Gail model. The Gail model uses the following 5 risk factors: age at evaluation, age at menarche, age at first live birth, number of breast biopsies, and number of first-degree relatives with breast cancer.

Prophylactic mastectomy may be considered medically necessary in patients at high risk or moderately increased risk of breast cancer. (For definitions of risk levels, see Policy Guidelines.)

Prophylactic mastectomy may be considered medically necessary in patients with lobular carcinoma in situ.

• Two or more first-degree relatives with breast cancer
• One first-degree relative and two or more second-degree or third-degree relatives with breast cancer
• One first-degree relative with breast cancer before the age of 45 years and one other relative with breast cancer
• One first-degree relative with breast cancer and one or more relatives with ovarian cancer
• Two second-degree or third-degree relatives with breast cancer and one or more with ovarian cancer
• One second-degree or third-degree relative with breast cancer and two or more with ovarian cancer
• Three or more second-degree or third-degree relatives with breast cancer
• One first-degree relative with bilateral breast cancer
• Presence of a BRCA1 or BRCA2 mutation in the patient consistent with a BRCA1 or 2 mutation in a family member with breast or ovarian cancer. (For further discussion of BRCA1 and 2 testing, refer to policy No. 2.04.02.)
• Presence of a p53 or PTEN mutation
• Received radiation therapy to the chest between the ages of 10 and 30 years

BlueCard/National Account Issues

Coverage for reconstructive breast surgery is typically provided for patients undergoing prophylactic mastectomies considered medically necessary by the plan.

This policy is based on a 1999 TEC Assessment that concluded that prophylactic mastectomy met the TEC criteria for patients with a family history of breast cancer. (1) However, patients with a family history represent a broad spectrum, ranging from those at high risk due to a family history consistent with hereditary breast cancer to those at more moderate risk, i.e., with a single affected relative.

The TEC Assessment focused on one 1999 study, a retrospective cohort analysis of 639 women with a family history of breast cancer who underwent bilateral prophylactic mastectomy between 1960 and 1993 at the Mayo Clinic. (2) A total of 90% of the mastectomies were subcutaneous. The patients were subdivided into 2 groups: high-risk patients had a family history suggestive of hereditary breast cancer (n=214), while the remaining 425 patients were arbitrarily considered to have a moderately increased risk. However, it should be emphasized that all women had some sort of family history of breast cancer. For each group, the reduction in the incidence of a mortality due to breast cancer was estimated by comparison to a control group (sisters of high-risk patients) or predicted outcomes (using the Gail model for moderate-risk patients).

For patients at moderate risk of breast cancer, 37.4 cancers were predicted by the Gail model, and 4 were observed for an incidence reduction of 89.5%. Approximately 13 women would have to have prophylactic mastectomy to prevent 1 cancer. For those at high risk of breast cancer, reduction in breast cancer incidence ranged from 90%–94%. Four to 8 women would need to undergo prophylactic mastectomy to prevent 1 occurrence of breast cancer.

While all patients in the Hartmann study had a family history of breast cancer, one should not conclude that all patients with a family history of breast cancer are candidates for a prophylactic mastectomy. Essentially the decision is a complicated patient-driven risk-benefit analysis of the individual cancer risk. While the cancer risk is greatest for those considered at high risk, whether or not the cancer risk associated with moderate-risk patients warrants a prophylactic mastectomy is a difficult question. While high risk is more objectively defined either by a family history alone or the presence of a BRCA1 or BRCA2 mutation, moderate risk may be conferred by a wide range of family histories in association with different breast pathologies.

The critical Hartmann study evaluated by the TEC Assessment was a retrospective cohort study that arbitrarily assigned all women not at high risk to be at moderate risk. It is not known what kind of risk assessment was performed, if any, prior to the mastectomy procedure. In the study, of the 425 women in the moderate risk category, 268 had at least 1 affected first-degree relative, 46 had 2 aunts, cousins, or both with breast cancer, and fewer second-degree or third-degree relatives. This group includes a wide variety of patients, with the spectrum potentially ranging from a patient with a first-degree relative with bilateral premenopausal breast cancer to a patient whose elderly mother is diagnosed with breast cancer. While these facts underline the importance of adequate counseling, it also underlines the arbitrary nature of defining a risk level above which prophylactic mastectomy would be considered medically necessary.

The Gail model has been used as a patient selection criteria to identify women at increased risk of breast cancer who would be candidates for chemoprevention with tamoxifen. The Breast Cancer Chemoprevention Trial accepted patients between the ages of 35 and 59 years with a 5-year predicted risk of breast cancer of 1.66%, according to the Gail model. (3) Presumably, at the very least, the predicted cancer risk for candidates for prophylactic mastectomy should exceed that of candidates for chemoprevention.

2008 Update
The policy was returned to active review and was updated using a search of MEDLINE through October 2008. The rationale section of the policy was updated to include additional factors associated with a high rate of cancer including the p53 and PTEN genetic mutations, and patients who received prior radiation therapy to the chest between the ages of 10 and 30 years of age whose risk of breast cancer can be almost 30% by age 55. (4) Many of the published studies identified reported on factors that influenced decisions about prophylactic mastectomy. A number of studies also discussed both patient satisfaction and quality of life after the procedure.
Professional Guidelines
This updated policy is in agreement with the current NCCN guidelines. (5)

References:

1. 1999 TEC Assessment; Tab 14
2. Hartmann LC, Schaid DJ, Woods JE et al. Efficacy of bilateral prophylactic mastectomy in women with a family history of breast cancer. N Engl J Med 1999; 340(2):77-84.
3. Fisher B, Costantino JP, Wickerham DL et al. Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study. J Natl Cancer Inst 1998; 90(18):1371-88.
4. Saslow D, Boetes C, Burke W et al. American Cancer Society Guidelines for breast screening with MRI as an adjunct to mammography. CA Cancer J Clin 2007; 57(2):75-89. Accessible online at http://caonline.amcancersoc.org/cgi/eprint/57/2/75.
5. National Comprehensive Cancer Network. Breast Cancer Risk Reduction. V.1.2008. Accessible at http://www.nccn.org/professionals/physician_gls/PDF/breast_risk.pdf. Accessed Nov 21, 2008.

Female Mastectomy as a Prophylaxis
Mastectomy, Female, as a Prophylaxis for Breast Cancer
Prophylactic Mastectomy