Prevalence, clinicopathological features, and prognosis of diabetes in pancreatic cancer: A single-center retrospective cohort study of 1620 patients.

[BACKGROUND] The interplay between pancreatic cancer (PC) and diabetes mellitus (DM) is complex, and may differ between new-onset DM (NODM) and long-standing DM (LSDM). We compared clinical features and prognosis across non-DM, NODM, and LSDM groups.

[METHODS] We retrospectively analyzed 1620 PC patients treated at the National Cancer Center (2008-2018). Patients were classified as non-DM, NODM (≤2 years), and LSDM (>2 years). Survival outcomes were assessed by Kaplan-Meier and Cox regression analyses, and mediation analysis was applied to evaluate indirect effects.

[RESULTS] Of 1620 patients, 536 (33.1 %) had DM, including 287 (53.4 % of DM) with NODM. NODM was associated with higher jaundice prevalence and elevated liver function markers; LSDM patients were older, had a greater prevalence of hypertension, and showed lower M stage. Non-DM patients had lower CA19-9, CA242, and CEA than both DM groups. Overall survival was significantly worse in NODM than in LSDM and non-DM. In curatively resected patients, DM status (non-DM/NODM/LSDM) independently predicted OS in multivariable models. Mediation analysis indicated total bilirubin accounted for 9.8 % of the adverse association between NODM and OS (ACME -0.46, 95 % CI -1.04 to -0.09; p = 0.008).

[CONCLUSION] DM is common in PC and associates with distinct clinicopathological profiles. NODM is linked to jaundice and poorer survival, while DM status serves as an independent prognostic factor in the curative-surgery subgroup, with part of NODM's adverse effect operating through bilirubin.