Contralateral prophylactic mastectomy increased survival in some younger patients with early-stage breast cancer

Contralateral prophylactic mastectomy improved five-year disease-specific mortality among women aged 18 to 49 years with early-stage ER–negative breast cancer, according to data collected in the SEER database.

Researchers reviewed data collected on 107,106 patients with unilateral disease who underwent mastectomy. Among those patients, 8,902 (8.3%) also had contralateral prophylactic mastectomy. Patients who had contralateral prophylactic mastectomy were more likely to be younger non-Hispanic whites with earlier-stage disease.

Univariate analysis showed that contralateral prophylactic mastectomy was associated with improved disease-specific survival for women with stage I to III breast cancer (for death, HR=0.63; 95% CI, 0.57-0.69).

After conducting risk-stratified multivariable regression analyses, the researchers found that in younger women with stage I or II ER–negative breast cancer, contralateral prophylactic mastectomy was associated with a reduction in the risk for disease-specific mortality (HR=0.68; 95% CI, 0.53-0.88). That was not the case among young women with early-stage ER–positive breast cancer.

These reductions translated into an increase in five-year adjusted breast cancer–specific survival of 4.8% (88.5% vs. 83.7%) in favor of contralateral prophylactic mastectomy among the young, early-stage ER-negative group vs. 0.5% (96.4% vs. 95.9%) among ER–positive women.

In an adjusted analysis, the researchers observed that the cancer-related survival associated with contralateral prophylactic mastectomy declined with age. Women aged younger than 50 years had a modest risk reduction (HR=0.84; 95% CI, 0.72-0.97), whereas patients aged older than 60 years saw no risk reduction.

Bedrosian I. J Natl Cancer Inst. 2010;102:1-9.