Impact of diabetes mellitus on clinical outcomes in patients undergoing surgical resection for pancreatic cancer: A retrospective, cohort study

OBJECTIVES:Diabetes mellitus (DM) has a bidirectional association with pancreatic cancer (PaC); however, its effect on clinical outcomes has not been thoroughly evaluated. We analyzed these data in a large sample of PaC subjects who had undergone surgical resection.METHODS:Subjects enrolled in the Mayo Clinic Pancreatic Cancer SPORE registry from 2000 to 2010 who had resection with curative intent were identified (n=488). Tumor size, cancer stage, and postoperative median survival were evaluated. Median survivals were compared with Kaplan-Meier curves and Cox proportional hazards regression modeling.RESULTS:A total of 275 (56%) subjects had DM before surgery. DM subjects had larger tumors compared with those without DM (3.6 cm vs. 3.3, P=0.002), even after controlling for covariates including age, body mass index, and tumor grade. Cancer stage at the time of surgery was not affected by DM status (P=0.575). Preoperative DM was not associated with an increased risk of death using a multivariable survival analysis (hazard ratio 1.06, 95% confidence interval 0.81-1.38, P=0.676). The median survival following cancer resection was similar between subjects with and without DM (24 vs. 26 months, P=0.610). In addition, postoperative survival was similar on the basis of the duration of DM (new-onset vs. long-standing) and prior use of antidiabetic treatments in diabetic subjects.CONCLUSIONS:PaC subjects with DM have larger tumors than nondiabetic subjects. Despite this observation, preoperative DM does not negatively impact the cancer stage at the time of surgery or postoperative survival. Thus, the effect of DM on tumor size is either overshadowed by early metastatic spread of the cancer or is mitigated by the tumor resection.