Clinical features of germline BRCA1/2 or ATM pathogenic variant positive pancreatic cancer in Japan

Background: There has been increasing interest into the role of germline BRCA1/2 pathogenic variants (gBRCA PV) and gATM PV and likely PV (PV and LPV; PV + LPV) in the carcinogenesis and treatment of pancreatic cancer (PC), but the clinical features have not been well described.

Methods: Patients with confirmed gBRCA PV and gATM PV + LPV PC treated at our hospital between April 2016 and December 2021, were retrospectively evaluated for clinical characteristics and outcomes.

Results: Twenty-two patients harbored gBRCA PV and three patients harbored gATM PV + LPV. Of the gBRCA PV patients, 81.8 % received platinum-based chemotherapy with favorable treatment outcomes with an objective response rate of 50.0 % (95 % CI: 23.0-77.0), median progression free survival (PFS) of 334 days, and median overall survival (OS) of 926 days from the initiation of first-line chemotherapy. The annual number of patients with gBRCA PV was two patients per year before January 2021 (when BRACAnalysis became available in Japan), and ten patients during the 10 months thereafter. Four patients (20 %) with gBRCA PV developed soft-tissue metastasis with progression. Two patients with gATM PV + LPV received platinum-based chemotherapy and the best response of those patients was partial response and stable disease and their OS from the initiation of first-line chemotherapy was 1192 and 989 days, and PFS was 579 and 140 days, respectively.

Conclusion: The diagnosis of gBRCA PV-positive PC has increased revealed in recent years. These tumors appear to be sensitive to platinum-based chemotherapy, with long term survival observed in gATM PV + LPV-positive patients.