INSULIN RESISTANCE IN PATIENTS WITH PANCREATIC AND COLORECTAL CANCER DIAGNOSED AGAINST THE BACKGROUND OF TYPE 2 DIABETES MELLITUS
Authors: Vatseba T. S. 
Published: January 2021

The aim of the study was to investigate insulin resistance in patients with pancreatic and colorectal cancer diagnosed in people with type 2 diabetes.
Materials and methods. 64 patients were examined. They were divided into the following groups: group I – healthy people (control group) (n = 16); group II – patients with type 2 diabetes without cancer (n = 28); group IIIa – patients with type 2 diabetes with pancreatic cancer (n = 10), group IIIb – patients with type 2 diabetes with colorectal cancer (n = 10). The study involved patients from specialized departments of the Ivano-Frankivsk Regional Hospital and the Precarpathian Clinical Oncology Center.
Blood insulin levels were determined by enzyme-linked immunosorbent assay, using Insulin ELISA diagnostic kits, EIA-2935. Fasting blood glucose was determined by glucose oxidase method. Compensation for diabetes was assessed by the level of glycated hemoglobin (HbA1c) and determined by ion exchange chromatography. Data analysis was performed using Statistica 12.0 (StatSoft Inc., USA). Differences between the values in the comparison groups were determined by Student’s t-test and were considered significant at P < 0.05.
Results. Patients with type 2 diabetes who were diagnosed with pancreatic cancer or colorectal cancer were older, compared with patients with type 2 diabetes without cancer (P < 0.05). Obesity was diagnosed in patients with colorectal cancer of group IIIb, their BMI was higher in comparison with patients of group IIIa who suffered from pancreatic cancer (P < 0.05). BMI in patients of group IIIa was lower than in control group (P < 0.05), in patients of group II (P < 0.05) and in patients of group IIIb with colorectal cancer (P < 0.05).
Compared with patients of group II, patients with pancreatic and colorectal cancer had significantly lower insulin levels (P < 0.05), but significantly higher fasting blood glucose levels (P < 0.05). Insulin resistance according to the HOMA-IR index (> 3.0) was detected in both types of cancer. The HOMA-IR index in patients with pancreatic cancer was significantly lower than in patients of group II (P < 0.05). The level of HbA1c in patients with type 2 diabetes without cancer and in patients with cancer diagnosed on the background of diabetes did not differ significantly (P > 0.05).
Prior to cancer detection, the same number of patients (50.0%) received metformin-free therapy in both the pancreatic cancer group and the colorectal cancer group. However, the duration of diabetes in patients with pancreatic cancer was 2.90 ± 2.60 years and was significantly shorter than in patients with colorectal cancer 9.70 ± 5.66 (P < 0.05). 80.0% of patients in group IIIa had a history of diabetes less than 5 years, and 80.0% of patients in group IIIb – more than 5 years.
Conclusions:

In patients with type 2 diabetes mellitus with pancreatic cancer, as well as in patients with colorectal cancer, insulin resistance was detected by the HOMA-IR index, which depended on the combined effect of insulin and hyperglycemia in patients with colorectal cancer and on the fasting blood glucose in patients with pancreatic cancer.
The absence of hyperinsulinemia, the short duration of type 2 diabetes in patients with pancreatic cancer may be indirect evidence of cancer induced pancreatogenic diabetes (T3cDM) in the majority of patients of this group.
For elderly patients with newly diagnosed diabetes mellitus without obesity, without hyperinsulinemia, screening for pancreatic cancer is recommended.