The impact of contralateral breast cancer on the outcome of breast cancer patients treated by mastectomy

PURPOSE To evaluate the clinical and pathological features of breast cancer patients who develop contralateral breast cancer (686) and assess the impa ct of the second breast cancer on their prognosis. PATIENTS AND METHODS This retrospective study includes 2136 women with stag e I-III breast cancer treated between 1927 and 1987 at the University of Ch icago Hospitals. A total of 132 (6.2%) developed CBC during a median follow -up period of 14.2 years: all of them were treated with mastectomy for both breast cancers. We compare the prognostic characteristics, treatments, and outcomes of patients who developed bilateral breast cancer with those who had only unilateral breast cancer (UBC). We also compare the features of th e first and the second tumors among patients with bilateral breast cancer ( BBC). RESULTS The annual incidence rate for CBC remained constant at an average r ate of 0.23%, resulting in a cumulative incidence rate of 6.2%. Patients wi th BBC were significantly younger than those with UBC (median age, 51 years vs 54 years). No other significant differences were observed between BBC a nd UBC patients. Among BBC patients, the second cancer was smaller (2.0 cm vs 3.0 cm) and was associated with a lower incidence of axillary associated with worse survival (hazard ratio = 1.46 in comparison with patients who d id not develop CBC, 95% CI of 1.09-1.95). On multivariate analysis, factors that decreased the disease-specific survival (DSS) in patients with BBC we re a higher number of positive lymph nodes of the first and second cancers, a larger size of the second cancer, and a shorter Interval between the two primaries. DISCUSSION At the time of diagnosis of first breast cancer, BBC patients we re significantly younger than UBC patients. The second cancer among the BBC patients was at an earlier stage than the first one; however, no differenc e was noticed in the pathological feature between the cancer in the UBC pat ients and the first cancer of BBC patients. There is an indication that the longer the interval between the two cancers, the better the survival of th e BBC patients.