Breast cancer and obesity link

As if we didn’t have enough bad news about weight gain, it is now believed that obesity increases the risk of breast cancer and worsens the prognosis among breast cancer patients.

With at least 67% of women living in the “overweight” category (BMI over 25) and nearly half of those in the “obese” category (BMI over 30), obesity has become an alarming cancer prevention issue that requires our immediate attention.

According to a recent article in the Annals of Oncology, obesity is a significant risk factor for many cancers including breast cancer, and, after tobacco use, obesity is the single greatest modifiable cancer risk factor. Excess weight also negatively affects prognosis after the cancer diagnosis because blood clots, infections, heart attacks, breathing difficulties and other problems occur more often among obese individuals, making cancer more dangerous to treat.

An association between obesity and breast cancer is particularly evident among post-menopausal women. Fat cells act as a “hormone pump,” increasing the body’s levels of insulin, leptin, estrogen and other steroid hormones that increase the potential for cancer.

Overweight women can have three times the level of circulating estrogen compared to leaner females, causing an unhealthy stimulation of breast gland cells. Breast cancer occurs when the cells reproduce and grow in an unregulated, “out-of-control” manner.

Leptin, another important hormone produced by fat tissue, also tends to cause cells to proliferate and may help set the stage for increased cancer risk.

As we become overweight and obese, we experience a chronic, low-level, or “subacute,” state of inflammation associated with increased cancer risk.

Subacute inflammation means that many of the body’s growth and metabolism systems are active, further stimulating the proliferation of cells and impairing normal regulation mechanisms.

The evidence is compelling that there is a strong link between obesity and breast cancer, particularly in post-menopausal females. Increased peptides from fat tissue, including estrogen and leptin, may provide part of the explanation, while subacute inflammation resulting from obesity further increases the cancer risk.

Most importantly, behind tobacco use, obesity is the single greatest modifiable cancer risk factor.

It is important that women utilize the treatments available including dietary modification, sustained exercise, weight loss medication, and weight-loss surgery for individuals with a BMI over 35.

A number of large studies, including published reviews by Flum and Christou, show reduced cancer rates after weight-loss surgery.

The bottom line is that weight gain can cause many adverse health effects, including cancer.

Women can improve their odds of avoiding cancer by quitting smoking and maintaining a normal, healthy weight. And, women can improve their odds of successfully completing cancer treatment in the future by guarding against excess weight gain and obesity now.

Dr. Kent C. Sasse, a Nevada based specialist in bariatric surgery and founder of the Obesity Prevention Foundation, is an expert on obesity.