“Obesity is on its way to replacing tobacco as the number one preventable / modifiable cause of cancer,” says Clifford Hudis, MD, the 2013-2014 President of the American Society of Clinical Oncology. Indeed, obese post-menopausal women have up to twice the risk of developing breast cancer as do their normal weight counterparts.
First, the biology behind the link to between obesity and cancer:
- Obese patients have increased levels of insulin and IGF-1 (insulin-like growth factor 1), therefore, greater stimulation IGF-1R (insulin-like growth factor receptors), which drive cell growth and cell division;
- Adipocytes have direct and indirect effects on cellular signaling molecules (stimulation of mTOR – mammalian target of rapamycin, which is one of the terminal Akt/PKB pathway effectors resulting in myc induction, and inhibition of AMP-activated protein kinase which blocks mTOR induction of myc);
- Obesity induces a chronic subacute level of inflammation, which promotes the development of cancer.
Second, what is the definition of obesity? The BMI (body mass index) chart from Baylor (http://www.baylorhearthospital.com/Knowing-Your-Numbers.html) shows the BMI given your height and weight. If you are 5’6” and weigh 230 pounds, or 6’2” and weigh 270 pounds, you are severely obese.
Third, some more startling facts:
- In colorectal cancer, obesity at the time of diagnosis is linked to a higher risk of recurrence and death;
- Obese and overweight women have 2-4 times the risk of developing endometrial cancer, and 90% of women with the most common type of endometrial cancer (Type 1) are obese;
- Individuals with a BMI of 30 or more, have 2 times the risk of developing pancreatic cancer;
- 30% of new cases of kidney cancer are attributable to obesity;
- BMI is positively correlated with prostate cancer progression to lethal disease, while inversely associated with incidence.
And finally, the obesity epidemic is only getting worse, especially in children where the rate of childhood obesity in 6 to 11 year olds increased from 5% in 1980 to 18% in 2010, and for 12 to 18 year olds it increased from 7% in 1980 to 18% in 2010.
Obesity of preventable and treatable. We must do a better job.