Importance
Although patients with resected pancreatic adenocarcinoma are at high risk for disease recurrence, few markers are available to inform patient outcomes.
Objective
To evaluate alterations of the four main driver genes for pancreatic adenocarcinoma and patient outcomes after cancer resection.
Design, Setting, and Participants
We analyzed protein expression and DNA alterations for KRAS, CDKN2A, SMAD4, and TP53 by immunohistochemistry and next-generation sequencing in formalin-fixed, paraffin-embedded tumors from 356 patients with resected pancreatic adenocarcinoma evaluated at three U.S. centers. Associations of driver gene alterations with disease-free survival (DFS) and overall survival (OS) were evaluated using Cox proportional hazards regression with estimation of hazard ratios (HR) and 95% confidence intervals (CI) and adjustment for age, sex, tumor characteristics, institution, and peri-operative treatment.
Main Outcomes
DFS and OS among patients with resected pancreatic adenocarcinoma
Results
Patients with KRAS mutant tumors had worse DFS and OS compared to patients with KRAS wild-type tumors, with median OS of 20.3 versus 38.6 months and 5-year OS of 13.0% versus 30.2%, respectively. Particularly poor outcomes were identified in patients with KRAS G12D-mutant tumors, who had median OS of 15.3 months. Patients whose tumors lacked CDKN2A expression had worse DFS and OS compared to patients whose tumors retained CDKN2A, with median OS of 19.7 versus 24.6 months and 5-year OS of 11.9% versus 19.5%, respectively. SMAD4 status was not associated with DFS or OS, while TP53 status was associated only with DFS (P=0.04). Patients had worse DFS and OS with greater number of altered driver genes. Compared to patients with 0-2 altered genes, those with 4 altered genes had HR for DFS of 1.79 (1.24-2.59; P<0.01) and OS of 1.38 (0.98-1.94; P=0.06). Five-year OS was 18.4% for patients with 0-2 gene alterations, 14.1% for 3 alterations and 8.2% for 4 alterations. Alterations in the four driver genes were not significantly associated with local recurrence as the first site of disease recurrence.
Conclusions and Relevance
Patient outcomes are associated with alterations of the four main driver genes in resected pancreatic adenocarcinoma.
Nearly 10% of PDAC patients harbor germline variants, although the majority lack somatic second hits, the therapeutic significance of which warrants further study.
Pancreatic cancer is the seventh leading cause of cancerrelated deaths worldwide with 432,242 related deaths in 2018. Unlike other cancers, the incidence of pancreatic cancer continues to increase, with little improvement in survival rates. We review the epidemiologic features of pancreatic cancer, covering surveillance and early detection in high-risk persons. We summarize data on worldwide incidence and mortality and analyze the 1975-2016 data from 9 registries of the National Cancer Institute's Surveillance, Epidemiology, and End Results study, on the overall burden of pancreatic cancer as well as age-, sex-, and race-specific incidence, survival rates and trends. It is important to increase our knowledge of the worldwide and regional epidemiologic features of and risk factors for pancreatic cancer, to identify new approaches for prevention, surveillance, and treatment.
Patients with HCCs, including those detected through surveillance, survived for short time periods in the absence of treatment, irrespective of their initial stage at diagnosis. Model for end-stage liver disease scores and levels of α-fetoprotein were prognostic factors, independent of Barcelona Clinic Liver Cancer stage. The lead time related to detection by surveillance was modest (<2 months) and therefore unlikely to explain the survival benefit associated with surveillance in previous studies.
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