Cancer and its relation to obesity

The World Health Organization estimates that more than 1.5 billion adults worldwide are overweight or obese. Once considered a problem only in high-income countries, overweight and obesity are now dramatically on the rise in low- and middle-income countries as well. Obesity increases the risk of several major diseases, including cardiovascular disease, cancer, and diabetes; it also increases rates of mortality in iniduals with these diseases. Obesity is quickly overtaking tobacco as the leading preventable cause of cancer. More than 40,000 cancer diagnoses each year are attributed to obesity and overweight. Obesity is also implicated in 15% to 20% of all cancer-related mortality.

Cancer types

• Breast: Obesity at diagnosis is linked to a 33% increase in the risk of breast cancer related and overall mortality in pre- and post-menopausal women with early-stage breast cancer.
• Colorectal: A recent meta-analysis of seven adjuvant chemotherapy trials in patients with stage II and III colorectal cancer treated with fluorouracil-based therapy found men with class II and III obesity (BMI ≥35kg/m2) and women with Class I obesity (BMI ≥30kg/m2) had significantly worse overall survival as compared to normal weight iniduals.
• Prostate: Obesity is associated with the development of biologically more aggressive and advanced prostate cancer.
• Childhood Leukemia: Obesity may be linked to poor outcomes in children with acute leukemia.

Being overweight/obese before hematopoietic cell transplantation is associated with lower survival and higher rates of acute graft-versus-host disease and treatment- related mortality.