Bilateral synchronous breast cancer: mode of detection and comparison of histologic features between the 2 breasts

BACKGROUND: Bilateral synchronous breast cancer is uncommon (accounting for 1.0%-2.6% of all patients with breast cancer), and most physicians do not accumulate a large personal experience of patients with this disease. We reviewed our experience with patients with bilateral synchronous breast cancer, focusing on the mode of detection and histologic features in the 2 breasts. METHODS: The charts of patients who were treated at this institution for bilateral synchronous breast cancer during the 15-year period of 1984 through 1999 were reviewed. Information regarding age, mode of detection, histopathologic features, treatment, and overall survival were analyzed. RESULTS: During the study period, 51 patients (all women) were treated at our institution for bilateral synchronous breast cancer. This comprised 2.1% of all patients (n = 2382 patients) treated for breast cancer during the same period of time. The first cancer was detected by palpation in 81% and by mammography in 14%. The corresponding figures for the contralateral cancer were 24% and 54%, respectively. The histologic type of cancer was identical in the 2 breasts in 29 patients (57%) and was different between the 2 breasts in 22 patients (43%). The overall 10-year survival rate was 63%. CONCLUSIONS: Bilateral synchronous breast cancer is often detected by mammography and is frequently of the same histologic type as the index cancer. A better awareness of the risk for this disease may help detect bilateral breast cancer earlier.