Women with BRCA1 mutations may still have an increased risk for developing rare, high-risk uterine cancers (serous cancer, carcinosarcomas, and leiomyosarcomas) even after undergoing risk-reducing salpingo-oophorectomy (RRSO) to remove their ovaries and fallopian tubes. Those were the findings reported in a late-breaking plenary study at the Society of Gynecological Oncology Annual Meeting on Women's Cancer (Late Breaking Abstract 5).
“While the absolute risk is still relatively low, it is much higher than we would have expected for these aggressive uterine cancers,” Noah D. Kauff, MD, the study's senior author and Director of Ovarian Cancer Screening and Prevention on the Gynecology Service at Memorial Sloan Kettering Cancer Center, said in a news release.
“Doctors should let their patients with BRCA1 mutations know that this report suggests they may be at risk for rare types of aggressive uterine cancer.”
The study included 525 women with BRCA1 or BRCA2 mutations seen at MSKCC who had had RRSO without hysterectomy and were followed prospectively for a median of 5.8 years.
High-risk uterine cancer was diagnosed in four women with BRCA1 mutations, a 2.1 percent risk of developing the disease—which is 26 times the average risk in the general population. No woman with a BRCA1 mutation was diagnosed with low-risk uterine cancer. None of the women with the BRCA2 mutation developed uterine cancer. Of the 525 women in the study, 296 had a BRCA1 mutation (56%), 226 had a BRCA2 mutation (43%), and three women had both (0.6%).
Also, of the four women who developed high-risk uterine cancer: three had had a prior breast cancer, and one woman had not; and, two of the women had been exposed to tamoxifen, and two had not.
In a follow-up interview, Kauff explained that previous studies have suggested that women with BRCA1 mutations may have a slightly increased risk of uterine cancers, but this is the first prospective study to suggest that the risk may be confined to the high-risk subtypes. Further data should examine additional cohorts of women with BRCA 1 and 2 mutations to confirm the results before recommendations are made to change the standard of care, he said—although this evidence does warrant discussion between physicians and patients that there may be an increased risk.
“This potential increased risk of uterine cancer is one reason a woman might consider having a hysterectomy at the same time she removes her uterine and fallopian tubes,” he said.
Ongoing research by Kauff and his team are analyzing molecular changes in these tumors to determine if there is a loss of BRCA1 function, which would suggest that the mutation played a role in the development of the tumor, he added.