PROPHYLACTIC MASTECTOMY FOR BRCA+ PATIENTS

Ann Surg. 2010 Feb 3. [Epub ahead of print]

Prophylactic Mastectomy in BRCA1 and BRCA2 Mutation Carriers: Very Low Risk for Subsequent Breast Cancer.

Kaas R, Verhoef S, Wesseling J, Rookus MA, Oldenburg HS, Peeters MJ, Rutgers EJ.

From the Departments of *Surgery, daggerClinical Genetics, double daggerPathology, and section signEpidemiology, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Plesmanlaan, Amsterdam.

AIM:: To examine the outcome of prophylactic mastectomy in a hospital-based series of BRCA1/2 gene mutation carriers with and without a history of breast cancer. PATIENTS AND METHODS:: A center-based consecutive series of 254 BRCA1/2 gene mutation carriers that had prophylactic mastectomy after a normal surveillance round including breast-magnetic resonance imaging were identified. One hundred forty-seven asymptomatic carriers underwent bilateral mastectomy and 107 symptomatic women had contralateral mastectomy after a mean cancer free interval of 3.6 years. All removed breasts were histopathologically examined. RESULTS:: In one asymptomatic BRCA2 carrier (0.7%) an occult small invasive breast cancer was diagnosed, while in 6 asymptomatic carriers (4.0% BRCA1 and 4.3% BRCA2) and in 5 symptomatic carriers (2.5% BRCA1 and 10.7% BRCA2) DCIS was detected at prophylactic mastectomy.No breast cancer occurred in the asymptomatic group after a postprophylactic follow-up period of 778 women-years. In the symptomatic carriers 1 invasive breast cancer was detected after 580 follow-up years.From age-, cohort-, and gene-specific reference data we calculated that 15 invasive first cancers in the asymptomatic carriers were prevented during follow-up. CONCLUSION:: One invasive breast cancer in 147 bilateral prophylactic mastectomies (0.7%) was detected, this makes a sentinel node procedure redundant and preoperative imaging vital. The prophylactic procedure is highly effective in preventing invasive breast cancer in BRCA1/2 mutation carriers. Since the remaining risk is less than 0.2%/woman-year, continued surveillance of the asymptomatic carriers is not warranted.