According to the US Centers for Disease Control and prevention, 41.9% of American adults are obese, of which 9.2% are even severely obese. Obesity can lead to a variety of health problems, including cancer. In fact, according to the CDC, overweight or obesity is associated with a higher risk of 13 different types of cancer.
People who are severely obese and have difficulty in losing weight sometimes resort to weight reduction surgery. There are two common types of gastric bypass surgery and sleeve gastrectomy. In gastric bypass surgery, the top of the stomach is transformed into a pouch and further connected to the small intestine. This bypasses the stomach and reduces the number of calories absorbed. In sleeve gastrectomy, about 80% of the stomach is removed, leaving a tubular stomach similar in size and shape to a banana.
According to a new study (asmbs2022) released at the annual meeting of the American Society for metabolic and bariatric surgery (ASMBS) today (June 7, 2022), people with obesity are at least twice as likely to suffer from certain types of cancer and 3.5 times as likely to die of the disease.
The researchers found that after weight loss surgery, the incidence rate of breast cancer (1.4% vs 2.7%), gynecological cancer (0.4% vs 2.6%), renal cancer (0.10% vs 0.80%), brain cancer (0.20% vs 0.90%), lung cancer (0.20% vs 0.60%) and thyroid cancer (0.10% vs 0.70%) decreased significantly.
The 10-year incidence rate of any new cancer in the surgical weight loss group was much lower than that in the non-surgical control group (5.2% vs. 12.2%), and the 10-year survival rate was much higher (92.9% vs. 78.9%). This retrospective study included 1620 patients who underwent gastric bypass surgery (1265 patients) or sleeve gastrectomy (355 patients) between september2001 and december2019, and 2156 patients who were matched by age, sex, and body mass index (BMI) and did not undergo surgery. Researchers estimate that surgical patients lost about 60 percent of their excess weight in 10 years.
Dr. Jared R. Miller, a general surgery and weight loss surgeon of Gundersen Lutheran health system, co-author of the study, said: "according to previous studies, we know that weight loss surgery can reduce cancer risk, but we are surprised by the degree of reduction of some cancers. The benefits of reducing cancer risk through weight loss surgery can not be ignored, and should be considered by patients with obesity and high risk of cancer."
The Centers for Disease Control and Prevention (CDC) estimates that more than 650000 obesity related cancers occur in the United States every year. From 2005 to 2014, most cancers related to overweight and obesity increased by 7%, while the rate of new cancers not related to overweight decreased by 13%. According to the American Society of Clinical Oncology (ASCO), obesity is an unrecognized major cancer risk factor, which is related to the deterioration of prognosis after cancer diagnosis.
Overweight and obesity can lead to changes in the body that may lead to cancer, including long-term inflammation and high insulin levels. The more overweight a person is, the longer he or she is overweight or obese, the greater the risk of cancer.
Dr. Shanu kothari, President of the American Academy of Medical Sciences, who was not involved in the study, said: "the data are increasing - when you treat obesity, you can prevent some cancers. Weight loss surgery has been proved to be the most effective long-term treatment for obesity. Now it is increasingly regarded as a preventive treatment, not only for cancer, but also for heart disease, stroke and type 2 diabetes."
In 2016, ASMBS issued a position statement on the relationship between obesity and cancer, as well as the role of weight loss surgery and the impact of weight loss not only on cancer risk, but also on survival after treatment.