Making Sense of the Cancer-Obesity Connection
Being overweight or obese raises the risk for many types of cancer, and a growing body of evidence suggests that other factors associated with obesity may encourage cancers to spread.
In fact, obesity is quickly overtaking tobacco as the leading preventable cause of cancer, according to the American Society of Clinical Oncology (ASCO). As many as 84,000 cancer diagnoses each year are attributed to obesity, and obesity or excess weight contributes to as many as one in five cancer-related deaths, ASCO states.
Cancers directly linked to obesity include:
- Esophageal cancer
- Breast cancer
- Endometrial (the lining of the uterus) cancer
- Colon cancer
- Rectal cancer
- Kidney cancer
- Pancreatic cancer
- Thyroid cancer
- Gallbladder cancer
Exactly how excess weight raises cancer risk is not fully understood, nor is it the same for each cancer. For example, fat produces excess amounts of the female sex hormone estrogen, and high levels of estrogen have been linked to breast and endometrial cancer. Another potential mitigating factor is inflammation. People who are obese have chronic inflammation throughout their body, and this has been linked to a host of diseases, including some cancers.
"All cancers are somewhat linked to obesity," says Mitchell Roslin, M.D., the chief of obesity surgery at Lenox Hill Hospital in New York City. "Some are linked directly, and others are indirectly linked," he adds.
"Growth factors and extra glucose associated with diabetes can feed tumors which is why obese people with cancer do worse stage for stage and have a higher recurrence rate than their thinner counterparts," he says. "Obesity creates a favorable metabolic milieu for cancer metastasis (spread)."
Weight Loss as Cancer Prevention
Losing weight can help lower some of the cancer risk associated with obesity. If every adult reduced his or her body mass index by 1 percent, 100,000 new cases of cancer could be prevented according to the ASCO.
There is no magic bullet for weight loss. The right way to lose weight for your friend may not be the right way for you. Talk to your doctor about your diet and exercise regimen along with what else you can do to lower your risk for cancer. This includes staying on top of regular screening tests as well.
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