Treatment of pancreatic adenocarcinoma in relation to survival in the U.S. Military Health System

Background: Pancreatic cancer has a high case fatality and relatively short survival after diagnosis. Treatment is paramount to improving survival, but studies on the effects of standard treatment by surgery or chemotherapy on survival in U.S. healthcare settings is limited. Further, variability in access to care may impact treatment and outcomes for patients. We aimed to assess the relationship between standard treatment(s) and survival of pancreatic adenocarcinoma in a population with access to comprehensive healthcare. Methods: We used the Military Cancer Epidemiology (MilCanEpi) database, which includes data from the Department of Defense cancer registry and medical encounter data from the Military Health System (MHS), to study a cohort of 1408 men and women who were diagnosed with pancreatic adenocarcinoma between 1998 and 2014. Treatment with surgery or chemotherapy in relation to overall survival was examined in multivariable time-dependent Cox regression models. Results: Overall, 75 % of 441 patients with early-stage and 51 % of 967 patients with late-stage pancreatic adenocarcinoma received treatment. In early-stage disease, surgery alone or surgery with chemotherapy were both associated with statistically significant 52 % reduced risks of death, but chemotherapy alone was not. In late-stage disease, surgery alone, chemotherapy alone, or both surgery and chemotherapy significantly reduced the risk of death by 42 %, 25 %, and 52 %, respectively. Conclusions: Our findings from the MHS demonstrate improved survival after treatment with surgery or surgery with chemotherapy for early- or late-stage pancreatic cancer and after chemotherapy for late-stage pancreatic cancer. In the era of immunotherapy and personalized medicine, further research on treatment and survival of pancreatic cancer in observational settings is needed.