Impact of Diabetes and Insulin Use on Prognosis in Patients With Resected Pancreatic Cancer: An Ancillary Analysis of NRG Oncology RTOG 9704

Abstract

Purpose: Diabetes mellitus (DM) has been proposed to be tumorigenic; however, prior studies of the association between DM and survival are conflicting. The goal of this ancillary analysis of RTOG 9704, a randomized controlled trial of adjuvant chemotherapy in pancreatic cancer, was to determine the prognostic effects of DM and insulin use on survival. Methods and Materials: Eligible patients from RTOG 9704 with available data on DM and insulin use were included. Overall survival (OS) and disease-free survival (DFS) were estimated using the Kaplan-Meier method, and variable levels were compared using log-rank test. Cox proportional hazards models were created to assess the associations among DM, insulin use, and body mass index phenotypes on outcomes. Results: Of 538 patients enrolled from 1998 to 2002, 238 patients were eligible with analyzable DM and insulin use data. Overall 34% of patients had DM and 66% did not. Of patients with DM, 64% had insulin-dependent DM, and 36% had non–insulin-dependent DM. On univariable analysis, neither DM nor insulin dependence were associated with OS or DFS (P >.05 for all). On multivariable analysis, neither DM, insulin use, nor body mass index were independently associated with OS or DFS. Nonwhite race (hazard ratio [HR], 2.18; 95% confidence interval [CI], 1.35-3.50; P =.0014), nodal involvement (HR, 1.74; 95% CI, 1.24-2.45; P =.0015), and carbohydrate antigen 19-9 (CA19-9) ≥90 U/mL (HR, 3.61; 95% CI, 2.32-5.63; P <.001) were associated with decreased OS. Nonwhite race (HR, 1.67; 95% CI, 1.05-2.63; P =.029) and CA19-9 ≥90 U/mL (HR, 2.86; 95% CI, 1.85-4.40; P <.001) were associated with decreased DFS. Conclusions: DM and insulin use were not associated with OS or DFS in patients with pancreatic cancer in this study. Race, nodal involvement, and increased CA19-9 were significant predictors of outcomes. These data might apply to the more modern use of neoadjuvant therapies for potentially resectable pancreatic cancer.