WEN-HUNG KUOYen A.M.-F.PO-HUANG LEEChen K.-M.JANN-YUAN WANGKING-JEN CHANGChen, Tony Hsiu HsiTony Hsiu HsiChenTsau H.-S.2020-03-242020-03-2420090007-0920https://www.scopus.com/inward/record.uri?eid=2-s2.0-60349091874&doi=10.1038%2fsj.bjc.6604898&partnerID=40&md5=95c63e738915b458825ae102c85683efhttps://scholars.lib.ntu.edu.tw/handle/123456789/478435As the epidemiological pattern of breast cancer in modernising Asian countries differs greatly from that in Western countries, it is worthwhile to investigate the long-term prognoses of unilateral and bilateral breast cancer in these nations. A retrospective cohort study composed of 1907 Taiwanese women was conducted to follow 1863 unilateral and 44 bilateral cases of breast cancer. Time-dependent Cox regression was used to assess the risk of breast cancer death by considering the time course of unilateral and bilateral tumour development. The 15-year survival rates were 68.37, 62.63, and 26.42% for unilateral, synchronous bilateral, and metachronous bilateral breast cancer, respectively. Differences among types were most apparent after 5 years of follow-up. After adjusting for significant prognostic factors, the risk of death for overall bilateral breast cancer was 2.50-fold greater (95% CI, 1.43-4.37) compared to unilateral breast cancer. The corresponding figures were 1.12-fold (95% CI, 0.42-3.02) and 6.11-fold (95% CI, 3.14-11.89) for synchronous and metachronous bilateral breast cancer, respectively. Taiwanese women, who are frequently diagnosed with breast cancer before 50 years of age, showed poorer survival for metachronous bilateral than for synchronous bilateral or unilateral breast cancer. Survival was markedly poorer compared to recent data from Sweden. ? 2009 Cancer Research UK.[SDGs]SDG3adult; article; bilateral cancer; breast cancer; cancer mortality; cancer risk; cancer staging; cancer survival; cohort analysis; comparative study; controlled study; female; follow up; human; major clinical study; priority journal; prognosis; proportional hazards model; retrospective study; risk factor; survival rate; Taiwan; Adult; Age of Onset; Breast Neoplasms; Cohort Studies; Female; Humans; Middle Aged; Prognosis; Retrospective Studies; Survival Rate; Taiwanjournal article10.1038/sj.bjc.6604898191906272-s2.0-60349091874