Prognosis of bilateral synchronous breast cancer in Vaud, Switzerland.

Abstract Out of 6084 first breast cancers registered between 1974 and 1993 in the Cancer Registry of the Swiss Canton of Vaud, 81 (1.3%) were synchronous bilateral breast cancers (BBCs). The 5-year relative survival rates were 73% for women with unilateral breast cancer (UBC) and 65% for those with synchronous BBC. The corresponding 10-year figures were 59% and 51%. This large, population-based series indicates that women with synchronous BBC have a moderately lower long-term survival than women with UBC.