International researchers from seven countries conducted a prospective study to determine risk reduction of ovarian, fallopian tube, or peritoneal cancer in women with a BRCA1 or BRCA2 mutation after oophorectomy and examine other factors, such as impact of this procedure on mortality and five year survival.
Using an international registry, 5,787 women completed questionnaires about their reproductive history, surgical history, and hormone use. The Hereditary Ovarian Cancer Clinical Study began in 1995, and the women were followed through 2011. The researchers examined the relationship between prophylactic oophorectomy and the rates of ovarian, fallopian tube, and primary peritoneal cancer, and the overall rate of death by age 70. For the 5,787 women in the study, 2,274 did not have an oophorectomy, 2,123 had already had undergone the procedure when they began the study, and 1,390 underwent oophorectomy during the study follow-up period. After an average follow-up period of 5.6 years (with longest follow-up duration of 16 years), 186 women developed ovarian, fallopian tube, or peritoneal cancer. However, the researchers found that oophorectomy reduced the risk of ovarian cancer by 80%. For women who carry a BRCA1 mutation, it was estimated that delaying the surgery until age 40 raised the risk of ovarian cancer to 4% and ovarian cancer risk increased to 14.2% if a woman waited until age 50 to have the surgery. Only one case of ovarian cancer was diagnosed before age 50 among BRCA2 mutation carriers in this study. Of the 511 women who died during this study, 333 died of breast cancer, 68 died from ovarian, fallopian tube, or peritoneal cancers, and the remainder died from other causes. Impressively, prophylactic oophorectomy reduced the risk of death by any cause by 77%.
Finch APM, Lubinski J, Moller P, et al. Impact of oophorectomy on cancer incidence and mortality in wmen with BRCA1 or BRCA2 mutation. Journal of Clinical Oncology; published online ahead of print 2/14/14: doi: 10.1200/JCO.2013.53.282