Surgical Decision Making in Genetically High-Risk Women: Quantifying Postoperative Complications and Long-Term Risks of Supplemental Surgery After Risk-Reducing Mastectomy

[News in breast oncology genetics for female and male population]

OBJECTIVES

Breast oncology genetics emerged almost 30 years ago with the discovery of the BRCA1 and BRCA2 genes. The evolution of analytical practices has progressively allowed access to tests whose results now have a considerable impact on the management of both female and male breast cancers. The Sénologie commission of the Collège national des gynécologues et obstétriciens français (CNGOF) asked five specialists in breast surgery, oncology and oncological genetics to draw up a summary of the oncogenetic testing criteria used and the clinical implications for the female and male population of the test results, with or without an identified causal variant. In the case of proven genetic risk, surveillance, risk-reduction strategies, and the specificities of surgical and medical management (with PARP inhibitors in particular) were updated.

METHODS

This summary was based on national and international guidelines on the monitoring and therapeutic management of genetic risk, and a recent review of the literature covering the last five years.

RESULTS

Despite successive technical developments, the probability of identifying a causal variant in a situation suggestive of a predisposition to breast and ovarian cancer remains around 10% in France. The risk of breast cancer in women with a causal variant of the BRCA1, BRCA2, PALB2, TP53, CDH1 and PTEN genes is estimated at between 35% and 85% at age 70. The presence of a causal variant in one of these genes is the subject of different recommendations for men and women, concerning both surveillance, the age of onset and imaging modalities of which vary according to the genes involved, and risk-reduction surgery, which is possible for women as soon as their risk level exceeds 30% and remains exceptionally indicated for men. In the case of breast cancer, PARP inhibitors are a promising new class of treatment for BRCA germline mutations.

CONCLUSION

A discipline resolutely focused on understanding molecular mechanisms, screening and preventive medicine/surgery, oncology genetics is currently also involved in new medical/surgical approaches, the long-term benefits/risks of which will need to be monitored.

Counselling Framework for Germline BRCA1/2 and PALB2 Carriers Considering Risk-Reducing Mastectomy

Female BRCA1/2 and PALB2 germline pathogenic variant carriers have an increased lifetime risk of breast cancer and may wish to consider risk-reducing mastectomy (RRM) for surgical prevention. Quantifying the residual lifetime risk and absolute benefit from RRM requires careful consideration of a patient's age, pathogenic variant, and their personal history of breast or ovarian cancer. Historically, patients have been counselled that RRM does not necessarily prolong survival relative to high-risk surveillance, although recent studies suggest a possible survival benefit of RRM in BRCA1 carriers. The uptake of RRM has increased dramatically over the last several decades yet varies according to sociodemographic factors and geographic region. The increased adoption of nipple-sparing mastectomy techniques, ability to avoid axillary staging, and availability of reconstructive options for most germline pathogenic variant carriers has helped to minimize the morbidity of RRM. Preoperative discussions should include evidence regarding postmastectomy sensation, the potential for supplemental surgery, pregnancy-related chest wall changes, and the need for continued clinical surveillance. Approaches that include sensation preservation and robotic nipple-sparing mastectomy are an area of evolving research that may be more widely adopted in the future.