Immunotherapy Is Associated with a Survival Benefit in Patients Receiving Chemotherapy for Metastatic Pancreatic Cancer.

Background: Immunotherapy (IT) has led to improved survival in several common cancers but success in pancreatic ductal adenocarcinoma (PDAC) has been limited. We analyzed if combination IT-chemotherapy (IT-CT) is associated with improved survival compared with chemotherapy alone (CT) in patients with metastatic PDAC. Methods: The National Cancer Database (2004-2016) was queried for patients who were diagnosed with metastatic PDAC. Patients were categorized by treatment group: CT only and IT-CT. Patients were excluded if they received radiation or a surgical procedure. The primary outcome was overall survival. Results: A total of 59,289 patients were identified, of whom 58,947 (99.4%) received CT and 342 (0.6%) received IT-CT. The IT-CT group was younger, had fewer comorbidities, and was more often treated at an academic center. The utilization of multiagent CT was similar between the groups. Median survival of patients treated with IT-CT was longer than CT alone (7.9 months vs. 6.3 months, p = 0.005). On multivariable analysis, receipt of IT-CT was associated with a survival advantage as compared with CT (hazard ratio = 0.86, 95% confidence intervals 0.76-0.97) when adjusting for demographics and type of CT regimen. Conclusion: In patients with metastatic PDAC, it appears that combination IT-CT may perhaps be associated with a survival advantage compared with CT alone.