Glucose metabolism during the acute prostate cancer treatment trajectory: The influence of age and obesity

Background & aims Obesity and age, key risk factors for aggressive prostate cancer, are associated with insulin resistance. Glucose-related parameters in patients with aggressive prostate cancer were compared with 2 reference groups: men of similar age and body mass index (BMI) without cancer, and healthy young men. Acute changes in these parameters following radiation treatment were also evaluated. Methods Nine patients with aggressive prostate cancer underwent metabolic assessments prior to treatment (baseline), 7 and 33 weeks post-baseline (post-treatment initiation). Baseline measures were compared with the 2 reference groups. Evaluations included: 1) fasting and oral glucose tolerance test (OGTT) blood samples for glucose, C-peptide, and insulin, 2) fasting blood samples for triglycerides, cholesterols, leptin, adiponectin, IL-6, and TNF-α, 3) body composition, 4) nutrition, and 5) physical activity. Results At baseline, patients had normal fasting glucose concentrations (<5.6 mM; 4.9 ± 1.2 mM) but impaired 2-h OGTT glucose concentrations (>7.8 mM; 8.7 ± 2.9 mM). Both reference groups had normal fasting (matched males: 4.2 ± 0.5 mM; young males: 3.7 ± 0.4 mM) and 2-h OGTT glucose concentrations (matched males: 5.6 ± 1.8 mM; young males: 3.1 ± 0.1 mM) that were significantly lower than patient values. During the OGTT, patients had higher insulin (120 min) and C-peptide (45, 60, 90, 120 min) concentrations compared to the matched males. At 7 weeks, 2-h OGTT glucose concentrations in patients improved to healthy ranges without changes in insulin, C-peptide, IGF-1, IGFBP-3 or other metabolic parameters. Conclusions At baseline patients with aggressive prostate cancer demonstrated impaired glucose tolerance compared with men of similar age and body size. Following treatment, glucose tolerance improved in the absence of changes in expected modifiers of glucose metabolism. These improvements may be related to treatment.