PCN164 BRCA MUTATION EPIDEMIOLOGY IN BREAST AND OVARIAN CANCER. IN PROSTATE AND PANCREATIC CANCER TOO?

Abstract

Mutations in the breast cancer (BRCA) 1 and/or BRCA 2 tumor suppressor genes are risk factors for hereditary breast-ovarian cancer syndrome and are typically associated with these cancers. There is evidence of these mutations in two other cancer sites: prostate cancer and exocrine pancreatic cancer. BRCA 1/2 genes are drug targets for poly ADP ribose polymerase (PARP) inhibitors. This study aims to estimate the number of newly diagnosed cases of breast, exocrine pancreatic, ovarian, and prostate cancer with BRCA mutation. Medline was systematically searched for studies reporting the prevalence of deleterious germline or somatic BRCA 1/2 mutation in unselected breast, exocrine pancreatic, ovarian, and prostate cancer patients in seven countries. The prevalence of BRCA 1/2 mutations was determined in the newly diagnosed incident population, and in the early and advanced/metastatic stages. These BRCA 1/2 prevalence estimates were applied to Decision Resources Group’s (DRG) incident, early stage, advanced, and recurrent case estimates for each cancer site to determine the number of incident cases and first line drug-treatable patients with BRCA 1/2 mutation. In 2018, there were 62,000 newly diagnosed incident cases of breast, exocrine pancreatic, ovarian, and prostate cancer with BRCA 1/2 mutation. The average BRCA 1/2 mutation prevalence across the seven countries ranged from 3% in breast cancer to 12% in ovarian cancer. Prostate cancer accounted for nearly 50% of the incident cases. With screening in prostate cancer leading to a large proportion of cases diagnosed with early disease thus reducing the risk of recurrence, ovarian cancer cancers form the majority (30%) of the 22,000 first-line drug treatable opportunities. The BRCA 1/2 mutations are not just restricted to breast and ovarian cancer, and due to the high risk of prostate cancer, the majority of newly diagnosed cancer patients with this mutation are in fact prostate cancer patients.