Bariatric Surgery Reduces Obesity-Related Cancer Risk

Maurie Markman, MD


December 12, 2022

This transcript has been edited for clarity.

I'm Dr Maurie Markman from Cancer Treatment Centers of America. I’m going to briefly discuss a component of a very complex and somewhat controversial topic. This relates to the long-term value of bariatric surgery in individuals who have very high BMI. The specific issue I'm addressing is the impact of bariatric surgery on subsequent cancer risk.

The question of bariatric surgery, of course, has been addressed extensively in the general medical literature and certainly in the surgical literature. The positive impact on the risk of diabetes and heart disease are well defined. But a particular question, one that obviously requires very long follow-up, about the reduction in cancer risk has been addressed in this very interesting paper that recently appeared in JAMA, entitled "Association of Bariatric Surgery With Cancer Risk and Mortality in Adults With Obesity."

In this paper, the authors looked at data from individuals who had undergone bariatric surgery from 2004 to 2017. A very large patient population of 30,000 was included. One fifth of these individuals had actually had bariatric surgery. In this case-control study, the remainder of the patients had similar BMI and had been followed without bariatric surgery. This analysis investigated 13 cancer types and the risk of developing particular cancer types that are known to be associated with obesity.

Of note, the difference in body weight between the individuals who underwent bariatric surgery vs those who did not, and were followed by other methods or other strategies of weight control, was 24.8 kg. Obviously, there was a lower weight in the individuals who had undergone bariatric surgery. Overall, there was 19.2% greater weight loss in the individuals who had had the surgery.

The bottom line, and the question being addressed in this case-control study of surgery vs no surgery, was the risk of cancer at 10 years. Overall, 2.9% of individuals who had undergone bariatric surgery experienced one of the cancers that were obesity related vs 4.9% of the individuals who underwent nonsurgical management. This is an absolute reduction of 2% in their risk of cancers, with a hazard ratio of 0.68 and a P value of .002 in favor of the bariatric surgery.

The second point of the article is looking not only at the incidence of cancer, but also at cancer mortality at 10 years. Among individuals who had undergone bariatric surgery, the risk of death from cancer was 0.8%, and the risk of death from cancer in the individuals who had the similar high BMIs who had not undergone surgery was 1.4% (hazard ratio, 0.52; P = .01).

Clearly, there is a substantial risk. The follow-up here was 10 years, so the risk may be even higher with longer follow-up. There's no question that bariatric surgery is an important management strategy. Bariatric surgery is not without its risks, including the surgery itself, the psychological impact, and what it does do to individuals. But there is no question that the potential benefit — and in this case, we're talking about cancer risk — is real.

The role that bariatric surgery should play in the future in population-based strategies to reduce cancer risk is uncertain but obviously needs to be discussed. There is clear evidence of a reduction in cancer risk that needs to be considered in our societal goals of impacting and preventing cancer in the future.

Thank you for your attention. I encourage you to read this paper if you're interested in the topic of bariatric surgery for cancer prevention. It is a very interesting paper and a very interesting analysis. Thank you.

Maurie Markman, MD, is president of medicine and science at Cancer Treatment Centers of America in Philadelphia. He has more than 20 years of experience in cancer treatment and gynecologic oncology research.

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