BRCA mutations and their clinical relevance in unselected pancreatic cancer population.

e16240 Background: Germline pathogenetic mutations in BRCA1/2 genes are described in pancreatic cancer patients (PCP) in about 5–9% of cases. The purpose of this study was to determine their relevance in an unselected consecutive cohort of PCP describing family and clinical history. Methods: Patients (pts) were recruited at a single cancer center from September 2019 to October 2020. Participants provided blood for DNA analysis; cancer family history and treatment records were reviewed; DNA was analyzed by Next Generation Sequencing and multiplex ligation-dependent probe amplification for germline variants in BRCA1/2 Results: 69 pts were included, 61 (88,4%) with locally advanced and metastatic pancreatic cancer received first line chemotherapy and 38 (62%) were full eligible for BRCA analysis; 8 out of 69 pts were BRCA screened even if in adjuvant setting, 10 patients are still under evaluation. Out of the 38 first line screened PCP germline BRCA mutations were found in 9 (19%): 4 pts (8,7%) with pathogenetic BRCA-2 variants (subgroup 1 – S1) and 5 pts (10,8%) with variants of unknown significances (VUSs), i.e. c.5339T>C and c.5096G>A in BRCA1 (subgroup 2 – S2). Samples from 29 pts were established as BRCA wild-type (subgroup 3 – S3). Pathogenetic BRCA-2 variants were observed in 2 male and 2 female (median age, 61.5 years, range 48-69), 3 out 4 without family history of breast, ovarian and pancreatic cancer, one patient (pt) had ovarian cancer family history. All pts had a negative personal history of others cancers. All S1 pts received FOLFIRINOX regimen achieving one complete response, 2 partials responses and 1 disease progression with RECIST criteria. The S2 included 2 male and 3 female (median age, 61 years, range 45-70) 2 with family history of pancreatic cancer, no pt had personal history of others cancers; 2 pts had stable disease and 3 disease progression receiving platinum-based regimen (4 pts) and gemcitabine/nabpaclitaxel (1 pt), respectively. Platinum responders were observed only in the well known pathogenetic BRCA-2 variants group with twice a median progression-free survival (PFS, months -ms-) as compared to the one observed in VUSs group. (>6 C.I. 95% 2- >12 ms; vs 3 ms, 95% C.I. 3-12 ms). S3 included 9 male and 20 female, (median age, 66 years, range 42-78); 5 pts had family history of pancreatic or breast cancer, 5 pts had a personal history of other cancers (breast and thyroid). In this group,16 pts received a platinum based regimen and 12 pts have been treated without platinum based regimen. Conclusions: Our results suggest that: 1) BRCA pathogenetic mutations rate (8,7%) is in line with literature data and seems not to be related with family or personal history, and to be associated with a better outcome; 2) No BRCA mutations were detected in patients over 70 years. 3) VUSs subgroup do not seem to benefit from platinum-regimen.