The Effect of Neoadjuvant Chemoradiation on Pancreatic Cancer-Associated Diabetes Mellitus

Objectives: Pancreatic cancer-associated diabetes mellitus (PaCDM) occurs in approximately 50% of patients. In patients with new-onset PaCDM undergoing neoadjuvant chemoradiation therapy before surgical resection, we hypothesized that pancreatic tumor destruction would lead to improvement in fasting glucose levels. Methods: A retrospective chart review was performed on patients with newly diagnosed pancreatic adenocarcinoma without a history of DM treated with neoadjuvant therapy at our center. All patients underwent combined modality neoadjuvant chemoradiation therapy, followed by surgical excision of the primary tumor. Results: Sixty-nine patients (31 with PaCDM) met inclusion criteria for the study; 18 had Evans grade II tumor kill response, 10 had grade III response, and 3 had grade IV response. In patients with grade IV response, the odds ratio (OR) for achieving a normal preoperative glucose was 5.0 (95% confidence interval [CI], 0.4-63.2), compared with grade III (OR, 0.5; 95% CI, 0.1-3.0) and grade II (OR, 1.1; 95% CI, 0.2-5.2). When adjusted for percent kilogram weight loss and tumor size in a multivariable regression model, the grade IV response became significant to an OR of 6.5 (95% CI, 1.2-77.3). Conclusions: In patients with new-onset PaCDM undergoing neoadjuvant chemoradiation therapy, fasting glucose response may mirror the extent of tumor destruction.