Association of diabetes and perineural invasion in pancreatic cancer

Diabetes and perineural invasion are frequently observed in pancreatic cancer. In this study, we tested possible relations between diabetes and perineural invasion in patients with resected pancreatic cancer. We conducted a retrospective study in 544 cases of resected pancreatic adenocarcinoma seen at the University of Texas MD Anderson Cancer Center during 1996-2011. Information on tumor characteristics, diabetes history, and survival time was collected by personal interview and medical record review. Patients with diabetes before or at the time of the pancreatic cancer diagnosis were considered diabetes only. Pearson χ(2) test was used to compare categorical variables in diabetic and nondiabetic groups. Kaplan-Meier plot, log-rank test, and Cox proportional regression models were applied in survival analysis. The prevalence of diabetes and perineural invasion was 26.5% and 86.9%, respectively, in this study population. Patients with diabetes had a significantly higher prevalence of perineural invasion (92.4%) than those without diabetes (85%) (P = 0.025, χ(2) test). Diabetes was not associated with other pathological characteristics of the tumor, such as tumor size, lymphovascular invasion, tumor grade, lymph node metastasis, and resection margin status. Diabetic patients had a significantly lower frequency of abdominal pain (P = 0.01), but a slightly higher frequency of weight loss (P = 0.078) as early symptoms of their cancer. Both diabetes and perineural invasion were related to worse survival and increased risk of death after adjusting for tumor grade and margin and node status (P = 0.036 and 0.019, respectively). The observed associations of diabetes and perineural invasion as well as reduced frequency of pain as early symptom of pancreatic cancer support the hypothesis that diabetes may contribute to pancreatic progression via the mechanism of nerve damage.