Breast cancer surgery trend changes since the introduction of BRCA1/2 mutation screening: a retrospective cohort analysis of 158 mutation carriers treated at a single institution.

Background: Bilateral mastectomy in women diagnosed with unilateral breast cancer is on the rise in the USA. One contributing factor is increased awareness of contralateral breast cancer risk. Positive testing for deleterious mutation in BRCA1/2 is a concrete measure of this contributing factor. We hypothesize that breast cancer surgery trend change is temporally associated with the introduction of BRCA1/2 genetic testing around 1996.
Methods: Our study cohort included 158 BRCA1 or BRCA2 mutation carriers diagnosed with unilateral breast cancer between 1963 and 2009. Mutation carriers with ovarian cancer or bilateral breast cancer were excluded. Breast surgery and breast reconstruction surgery trends were analyzed according to year of breast cancer diagnosis or when bilateral mastectomy was performed, respectively.
Results: Surgery trends changed significantly over time. We observed a significant drop in the rate of unilateral mastectomy (P < 0.001) after the period 1996-2000, and the rate of bilateral mastectomy appears to be on the rise, up to 30.3% between 2006 and 2009. Breast reconstruction trends also changed significantly over time, with a significant rise in the rate of free flap reconstruction to 58.8% between 2006 and 2009.
Conclusions: Our results demonstrated a significant decrease in unilateral mastectomy with a rise in bilateral mastectomy after the period 1996-2000, a period which encompassed the year when genetic testing of the two BRCA1/2 genes became commercially available, hence supporting our hypothesis.