Obesity and Cancer: Biological Links and Treatment Implications

Obesity is an epidemic disease and correlates with cardiovascular diseases increasing the overall mortality. However, it has been recently demonstrated that cancer is an unexpected consequence of obesity. In most of the studies, it is evaluated with body mass index (BMI): high BMI increases cancer risk and reduces survival of many solid tumors. The main biologic and clinic topics regarding obese cancer patients are here presented and discussed. Hyperinsulinemia and Insulin-like Growth Factors (IGFs) are among the most important links between cancer and obesity. However, adipose tissue (AT) also produces sex hormones, pro-inflammatory cytokines and hypoxia which in turn promote initiation and progression of tumors. One of the major clinic concern about obese cancer patients is the risk of chemotherapy-related toxicity. Previous studies showed that obese patients do not experience significant increased toxicity compared to non-obese patients. Thus, the increasing incidence and scientific knowledge of obesity should prompt the researchers to study for personalization of therapy in obese patients with cancer rather than for the simple chemotherapy "depotentiation". It has been demonstrated that weight loss reduces cancer risk and can ameliorate compliance to therapy. Thus, social politics as well as therapies against obesity may impact on cancer risk, treatment and survival.