An Emerging Entity: Pancreatic Adenocarcinoma Associated with a Known BRCA Mutation: Clinical Descriptors, Treatment Implications, and Future Directions

Abstract

BRCA1 and BRCA2 germline mutations are associated with an elevated risk for pancreas adenocarcinoma (PAC). Other BRCA-associated cancers have been shown to have greater sensitivity to platinum and poly(ADP-ribose) polymerase (PARP) inhibitors with better clinical outcomes than in sporadic cases; however, outcomes in BRCA-associated PAC have not been reported. Patients with a known BRCA1 or BRCA2 mutation and a diagnosis of PAC were identified from the Gastrointestinal Oncology Service, Familial Pancreas Cancer Registry, and Clinical Genetics Service at Memorial Sloan-Kettering Cancer Center. Fifteen patients, five male, with a BRCA1 (n = 4) or BRCA2 (n = 11) mutation and PAC and one patient with a BRCA1 mutation and acinar cell carcinoma of the pancreas were identified. Seven female patients (70%) had a prior history of breast cancer. Four patients received a PARP inhibitor alone or in combination with chemotherapy; three demonstrated an initial radiographic partial response by Response Evaluation Criteria in Solid Tumors whereas one patient had stable disease for 6 months. Six patients received platinum-based chemotherapy first line for metastatic disease; five of those patients had a radiographic partial response. BRCA mutation-associated PAC represents an underidentified, but clinically important, subgroup of patients. This is of particular relevance given the ongoing development of therapeutic agents targeting DNA repair, which may potentially offer a significant benefit to a genetically selected population. We anticipate that further study and understanding of the clinical and biologic features of BRCA-mutant PAC will aid in the identification of tissue biomarkers indicating defective tumor DNA repair pathways in sporadic PAC.