Clinical and molecular features of early onset pancreatic adenocarcinoma.

Pancreatic adenocarcinoma (PDAC) is a major health burden and may become the second cause of death by cancer in developed countries. The incidence of early-onset pancreatic cancer (EOPC, defined by an age at diagnosis <50 years old) is increasing. Here, we conducted a study of all PDAC patients followed at our institution. Patients were classified as EOPC or non-early onset (nEOPC, >50). Eight hundred and seventy eight patients were included, of which 113 EOPC, exhibiting a comparable performance status. EOPC were more often diagnosed at the metastatic stage (70.0% vs 58.3%) and liver metastases were more prevalent at diagnosis (60.2% vs. 43.9%). The median overall survival (OS) from diagnosis was 18.1 months, similar between EOPC and nEOPC. Among patients who underwent surgery, recurrence-free survival was similar between age groups. Among metastatic patients, first line progression free survival was similar but EOPC received more treatment lines (72.3% vs. 58.1% received ≥2 lines). Regarding molecular alterations, the mean tumor mutational burden (TMB) was lower in EOPC (1.42 vs. 2.95 mut/Mb). The prevalence of KRAS and BRCA1/2 mutations was similar, but EOPC displayed fewer alterations in CNKN2A/B. Fifty eight patients (18.6%) had actionable alterations (ESCAT I-III) and 31 of them received molecularly matched treatments. On the transcriptomic level, despite its clinical aggressiveness, EOPC was less likely to display a basal-like phenotype. To conclude, EOPC were diagnosed more frequently at the metastatic stage. OS and 1st line PFS were similar to nEOPC. EOPC displayed specific molecular features, such as a lower TMB and fewer alterations in CDKN2A/B.