Blood glucose & pancreatic cancer

EPIDEMIOLOGICALLY, it is known that type 2 diabetes is a risk factor for pancreatic cancer, and analyses of 20 epidemiological studies showed that the relative risk for this cancer in patients with diabetes for five years was almost double that in patients without diabetes.

In a meta-analysis of nine prospective observational studies, with a total of 2,408 patients with pancreatic cancer, Taiwanese researchers evaluated the quantitative dose-response association between blood glucose concentration and risk for pancreatic cancer. Their work is published in the latest issue of the British Medical Journal. The researchers found that there was a strong linear dose-response relation between fasting blood glucose concentration and incidence of pancreatic cancer: Every 10.1 mg/dl increment in fasting glucose was associated with a 14 per cent increase in incidence of pancreatic cancer. Similar results were also obtained when only fasting blood glucose concentrations in the pre-diabetes range were considered.

The researchers attribute this dose-response relationship to the fact that pancreatic cancer cells depend heavily on glucose for growth. A normal pancreas metabolises glucose through oxidative phosphorylation. Pancreatic cancer cells, on the other hand, preferentially metabolise glucose through aerobic glycolysis, which generates less energy. To compensate for the inefficient energy production and meet the growing need for energy and biosynthesis, pancreatic cancer cells have a high requirement for glucose and exhibit increased glucose uptake. Therefore, hyperglycaemia might increase the risk of pancreatic cancer by providing more glucose to fuel tumour growth.

According to the researchers, pancreatic adenocarcinoma is the most lethal cancer, with a five-year survival rate of less than 5 per cent. Its incidence and mortality rates are increasing; it is the fifth and fourth leading cause of cancer deaths in the U.S. and the U.K. respectively and globally causes an estimated 227,000 deaths a year. The incidence in India is low (0.5-2.4/100,000 men and 0.2-1.8⁄100,000 women). It is higher in the urban male populations of western and northern parts of India but time trends show that this figure is increasing. Indeed, with rapidly increasing incidence of type 2 diabetes, the incidence of pancreatic cancer will also rise. As about 85 per cent of the tumours cannot be surgically removed at diagnosis, prevention through modification of its risk factors is especially important, the researchers point out. Thus, preventing and treating pre-diabetes and type 2 diabetes by optimising diet, physical activity, etc. could prevent pancreatic cancer.