Characteristics Associated With Survival in Surgically Nonresected Pancreatic Adenocarcinoma in the Military Health System

Abstract

Objectives: Pancreatic cancer is often diagnosed at advanced stages with high-case fatality. Many tumors are not surgically resectable. We aimed to identify features associated with survival in patients with surgically nonresected pancreatic cancer in the Military Health System. Methods: We used the Military Cancer Epidemiology database to identify the Department of Defense beneficiaries aged 18 and older diagnosed with a primary pancreatic adenocarcinoma between January 1998 and December 2014 who did not receive oncologic surgery as treatment. We used Cox Proportional Hazard regression with stepwise procedures to select the sociodemographic and clinical characteristics related to 2-year overall survival, expressed as adjusted hazard ratios (aHR) and 95% CIs. Results: Among 1148 patients with surgically nonresected pancreatic cancer, sex, race-ethnicity, marital status, and socioeconomic indicators were not selected in association with survival. A higher comorbidity count (aHR 1.30, 95% CI: 1.06-1.59 for 5 vs. 0), jaundice at diagnosis (aHR 1.57, 95% CI: 1.33-1.85 vs. no), tumor grade G3 or G4 (aHR 1.32, 95% CI: 1.05-1.67 vs. G1/G2), tumor location in pancreas tail (aHR 1.49, 95% CI: 1.22-1.83 vs. head) or body (aHR 1.30, 95% CI: 1.04-1.62 vs. head), and metastases were associated with survival. Patients receiving chemotherapy (aHR 0.66, 95% CI: 0.57-0.76) had better survival compared with no treatment. Conclusions: In a comprehensive health system, sociodemographic characteristics were not related to survival in surgically nonresected pancreatic cancer. This implicates access to care in reducing survival disparities in advanced pancreatic cancer and emphasizes the importance of treating patients based on clinical features.