Incidence and Prevalence of Intraductal Papillary Mucinous Neoplasms in Individuals With BRCA1 and BRCA2 Pathogenic Variant

Background:The natural history of branch-duct intraductal papillary neoplasm (BD-IPMN) in BRCA1/2 patients is unknown. Our goal was to estimate the incidence and prevalence of BD-IPMN and other pancreatic lesions in BRCA1/2 patients and compare it to that for average-risk individuals. Methods:We identified a cohort of BRCA1/2 patients followed at our institution between 1995 and 2020. Medical records and imaging results were reviewed to determine prevalence of pancreatic lesions. We then identified those who had undergone follow-up imaging and determined the incidence of new pancreatic lesions. We categorized pancreatic lesions as low, intermediate, or high-risk based on their malignant potential. Results:During the study period, 359 eligible BRCA1/2 patients were identified. Average patient age was 56.8 years, 88.3% were women, and 51.5% had BRCA1. The prevalence of low-risk pancreatic lesions was 14.4%, intermediate-risk 13.9%, and high-risk 3.3%. The prevalence of BD-IPMN was 13.6% with mean cyst size 7.7 mm (range: 2 to 34 mm). The prevalence of pancreatic cancer was 3.1%. Subsequent imaging was performed in 169 patents with mean follow-up interval of 5.3 years (range: 0 to 19.7 y). The incidence of BD-IPMN was 20.1%, with median cyst size 5.5 mm (range: 2 to 30 mm). The incidence of pancreatic cancer was 2.9%. BRCA2 patients were almost 4-times more likely to develop pancreatic cancer than BRCA1 patients, however, there was no difference in incidence or prevalence of BD-IPMN. Conclusions:Incidence and prevalence of BD-IPMNs in BRCA1/2 patients was similar to that reported for average-risk individuals. BRCA2 patients were more likely than BRCA1 patients to develop pancreatic cancer but had similar rates of BD-IPMN.