Abstract P5-13-09: Evaluation on the risk factors and prognosis for patients with synchronous bilateral breast cancer in a Chinese cohort

Abstract

Abstract Background: There has been an increasing rate of synchronous bilateral breast cancers, mainly because of the increased morbidity, improved detection abilities, better prognosis and higher life expectancy of breast cancer patients. However, evidences in the literature regarding the risk factors of bilateral breast cancers are scare, and the survival of synchronous bilateral breast cancers still remain controversies. The purpose of the present study is to investigate the risk factors and prognosis of bilateral breast cancers in a Chinese cohort. Methods: The present study included 181 patients with synchronous bilateral breast cancer and 10,831 patients with unilateral breast cancer treated in Fudan University Shanghai Cancer Center between Jan 2007 and Dec 2012. Patients with metastases or inflammatory diseases, or metachronous bilateral breast cancer (after 6 months of first cancer) were excluded. Age of the cases, family history, menopausal status, histology types, pathological stages, types of accompanied benign lesions, and patterns of surgeries and adjuvant therapies were examined to investigate the risk factors of bilateral breast cancers. Results: Patients with synchronous bilateral breast cancer were significantly elder than those with unilateral breast cancer (mean age 53 yrs vs. 51yrs, p<0.001). Presence of sclerosing adenoma and lobular carcinoma component were the two independent risk factors of early-stage synchronous bilateral breast cancer, with the relative risk rate at 5.52 (95% CI: 3.04-10.01) and 5.00 (95% CI: 2.64-9,47), respectively. The rate of in situ carcinoma with or without microinvasion was significantly higher in patients with sclerosing adenoma associated synchronous bilateral breast cancers at 64.3%. With a median follow-up of 35 months, the disease free survival for synchronous bilateral breast cancer was 95.0%, similar to that of unilateral breast cancer. However, for synchronous bilateral breast cancer patients with N3 disease or previously received neoadjuvant therapy (20 cases), the 1.5 year-disease free survival was merely 50%, significantly worse than that of unilateral breast cancer with N3 disease or previous neoadjuvant therapy. Conclusion: The rate of synchronous bilateral breast cancer was higher in patients with sclerosing adenosis or lobular carcinoma component. The prognosis for early-stage synchronous bilateral breast cancer was similar to those with early-stage unilateral breast cancer. However, among patients with N3 disease or previously received neoadjuvant therapy, synchronous bilateral cohort was associated to worse survival compared with unilateral cohort. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-13-09.