To the Editor Gangi et al1 describe survival among a cohort of 364 women who received a diagnosis of epithelial ovarian cancer with up to 14 years of follow-up (median follow-up, 5.1 years). They conclude that women with a BRCA1 or BRCA2 mutation (37% of the women in their sample) who subsequently develop breast cancer have a higher survival rate than those who do not. We are concerned that the conclusions regarding survival are subject to immortal time bias.
Alexander Liede, Ping Sun, Steven Narod. Effect of Breast Cancer After Ovarian Cancer on Mortality for BRCA Mutation Carriers. JAMA Surg. 2015;150(5):490–491. doi:10.1001/jamasurg.2015.0193