CONTRALATERAL BREAST CANCER IN WOMEN WITH EARLY STAGE BREAST CANCER

Abstract

Background: There is uncertainty about the lifetime risk of contralateral breast cancer (CBC) in a woman who is diagnosed with early stage breast cancer. Studies report a wide range of rates of CBC between 2% and 35%.

Objectives: (i) To determine the risk of CBC in women with early stage breast cancer, and (ii) to evaluate the risk of CBC in women who undergo adjuvant systemic treatment and adjuvant radiation treatment.

Methods: PubMed, Ovid MEDLINE, EMBASE, Healthstar, Cochrane Central Register for Controlled Trials were searched. Studies were included if participants had: unilateral invasive breast carcinoma; 5 years of median follow-up; a minimum of 100 participants. Randomized controlled trials were included for the meta-analysis. A random-effects meta-analysis was used to estimate the pooled rate of CBC.

Results: 4571 articles were extracted out of which 22 randomized controlled trials were included in the final meta-analysis. The overall pooled rate of CBC was 0.36% per year, (95% CI, 0.32% - 0.41%). The rate of CBC in studies without adjuvant systemic treatment was higher than the rate without such treatment, 0.56% per year (95% CI, 0.40% to 0.77%) versus 0.35% per year (95% CI, 0.31% to 0.40%). The rate of CBC in studies with adjuvant radiation treatment was 0.26% per year (95% CI, 0.18% to 0.39%) which is similar to the rate in studies with radiation.

Conclusions: The rate of CBC in women with early stage breast cancer is relatively low. This is important for breast cancer patients who are considering contralateral prophylactic mastectomy.