Risk of endocrine pancreatic insufficiency in patients receiving adjuvant chemoradiation for resected gastric cancer

Abstract Background Adjuvant radiotherapy combined with 5-fluorouracil based chemotherapy has become the new standard after curative resection in high risk gastric cancer. Beside many complications due to surgery, the addition of chemotherapy and radiotherapy as adjuvant treatment may lead to both acute and late toxicities. Pancreatic tissue irradiation during this adjuvant treatment because of incidental and unavoidable inclusion of the organ within the radiation field may affect exocrine and endocrine functions of the organ. Materials and methods Fifty-three patients with gastric adenocarcinoma were evaluated for adjuvant chemoradiotherapy after surgery. While 37 out of 53 patients were treated postoperatively due to either serosal or adjacent organ or lymph node involvement, 16 patients without these risk factors were followed up regularly without any additional treatment and they served as the control group. Fasting blood glucose (FBG), hemoglobin A1c (HBA1c), insulin and C-peptide levels were measured in the control and study groups after the surgery and 6 months and 1 year later. Results At the baseline there was no difference in FBG, HbA1c, C-peptide and insulin levels between the control and the study groups. At the end of the study there was a statistically significant decline in insulin and C-peptide levels in the study group, (7.5 ± 6.0 vs 4.5 ± 4.4 IU/L, p : 0.002 and 2.3 ± 0.9 vs 1.56 ± 0.9 ng/ml, p : 0.001) respectively. Conclusions Adjuvant radiotherapy in gastric cancer leads to a decrease in beta cell function and insulin secretion capacity of the pancreas with possible diabetes risk. Radiation-induced pancreatic injury and late effects of radiation on normal pancreatic tissue are unknown, but pancreas is more sensitive to radiation than known. This organ should be studied extensively in order to determine the tolerance doses and it should be contoured during abdominal radiotherapy planning as an organ at risk.