Insulin resistance, growth factors and cytokine levels in overweight women with breast cancer before and after chemotherapy

Abstract

Objective: To evaluate insulin values, insulin resistance, growth factors and cytokine levels in women suffering from breast cancer and the effect of chemotherapy on these parameters.

Design: In a prospective study, glucose and insulin values were determined in ten previously undiagnosed diabetic postmenopausal women with stage IV breast cancer (hepatic metastases excluded) during an oral glucose tolerance test (OGTT) carried out after a glucose load of 75 g. At baseline, leptin, Interleukin-1 (IL-1), Interleukin-6 (IL-6), Interleukin-8 (IL-8), Insulin-Growth Factor-1 (IGF-1), Tumor-Necrosis-Factor-alpha (TNF-alpha), Vascular Endothelial Growth Factor (VEGF) and Platelet Derived Growth Factor (PDGF) levels were also determined using appropriate methodolody. Insulin resistance and beta-cell function were calculated (HOMA-model). All women were evaluated prior to and after chemotherapy applied for 6 months.

Results: 1) Insulin levels at 120 minutes of the OGTT were higher before compared to post-chemotherapy (Mean+/-SD: 170.39+/-78.07 vs 111.75+/-76.19, p=0.037). 2) Body mass index (BMI) was an important predictor of post-glucose load insulin levels both before (coefficient=1.051, p=0.004) and after chemotherapy (coefficient=0.711, p=0.003). 3) Before chemotherapy BMI values were positively related to PDGF levels (rs=0.685, p=0.029), while after chemotherapy this relationship became non-significant (rs=0.188, p=0.603). Before chemotherapy there was a negative relationship between VEGF and waist circumference (coefficient= -0.542, p=0.023).

Conclusions: Post-glucose load insulin values significantly decrease after chemotherapy. There is a positive relationship between BMI and post-glucose load insulin before and after chemotherapy. The contribution of the reduction in insulin, a known growth factor, to the outcome of chemotherapy in these patients remains speculative at present.