Impact of the Duration of Diabetes Mellitus on the Outcome of Metastatic Pancreatic Cancer Treated with Gemcitabine: A Retrospective Study

OBJECTIVE: To assess the impact of the duration of diabetes mellitus (DM) on the outcomes of pancreatic cancer patients undergoing chemotherapy. METHODS: We reviewed the medical records of patients with metastatic pancreatic cancer who received gemcitabine monotherapy as the standard therapy before the introduction of combination regimens. The treatment outcomes of gemcitabine were compared among three groups classified according to the duration of DM: no DM, short DM (<4 years), and long DM (≥4 years). RESULTS: Among 350 patients, 218, 87, and 45 patients were classified into the no DM, short DM, and long DM groups, respectively. In comparison to the no DM group, the univariate hazard ratios (HRs) for progression-free survival (PFS) and overall survival (OS) were 1.44 [95% confidence interval (CI), 1.02-2.02; p=0.027] and 1.33 (95% CI, 0.93-1.89; p=0.081), respectively, in the long DM group, and 1.12 (95% CI, 0.85-1.46; p=0.426) and 1.06 (95% CI, 0.81-1.40; p=0.678), respectively, in the short DM group; the multivariate-adjusted HRs were 1.33 (95% CI, 0.94-1.89; p=0.103) and 1.37 (95% CI, 0.95-1.98; p=0.095) in the long DM group and 1.12 (95% CI, 0.85-1.47; p=0.410) and 1.10 (95% CI, 0.82-1.46; p=0.533) in the short DM group. The survival outcomes of the long DM group tended to remain poorer in analyses using different cutoffs of DM duration as, well as in hospital-specific analyses. CONCLUSION: Long-standing DM may be associated with shorter PFS and OS in patients with metastatic pancreatic cancer.