Undergoing Bariatric Surgery Could Lower Cancer Risk in Patients with Obesity

Gregory Weiss, MD

Obesity continues to be a significant burden leading to a host of comorbid conditions including cardiovascular disease, diabetes, and even cancer. Evidence suggests that obesity puts patients at twice the risk for certain types of cancer and makes them 3.5 times more likely to die from those cancers when compared to obese patients who have undergone bariatric surgery.¹

Bariatric surgery also known as weight reduction surgery, has been shown in the past to reduce the risk for certain types of cancer. What was not known was the extent weight reduction surgery might mitigate that cancer risk. In an abstract presented at this year’s annual meeting of the American Society for Metabolic and Bariatric Surgery (ASBMS), Jared Miller, MD, and colleagues presented the results of their retrospective cohort study comparing cancer risk in bariatric patients to obese patients not receiving weight reduction surgery.

In total the authors looked at 2,121 obese patients undergoing weight reduction surgery comparing them to 5,528 non-surgical patients with body mass indices (BMI) greater than 30kg/m2.¹ The results immediately revealed a significantly lower risk of a new cancer diagnosis in the surgical weight reduction group when compared to non-surgical matched control patients.¹ The likelihood of a new cancer diagnosis in the weight reduction surgery group was 5.3% compared to 13.4% in the control group.¹

“The benefits of cancer risk reduction through weight-loss surgery cannot be ignored and should be a consideration for patients with obesity and at high risk for cancer,” said Miller.

Unfortunately, obesity is a problem that is not going away. While obesity is most often related to diabetes and cardiovascular disease, the Centers for Disease Control and Prevention (CDC) estimate that nearly three-quarters of a million obesity-related cancers are diagnosed each year in the United States.² The authors believe that obesity-related cancers are not only increasing but may be significantly reduced through the use of widespread bariatric surgery. This is a sentiment echoed by the American Society of Clinical Oncology which, in their position statement on cancer and obesity, points out that obesity is a major risk factor for cancer and is associated with worse outcomes after cancer diagnosis.³

Although not free from risk, bariatric surgery has been shown produce meaningful and durable weight loss which is associated with resolution or reductions in severity of comorbid diabetes, cardiovascular disease, and hypertension. The ASMBS estimates that over a quarter of a million bariatric surgeries were performed in the United States in 2019. Unfortunately, less than 1% of obese Americans eligible for weight reduction surgery end up receiving it. This dramatic underutilization of this proven procedure is an important target for progress.

Cancer reduction is just the latest headline where bariatric surgery is concerned.

“Weight-loss surgery has proven to be the most effective long-term treatment for obesity and now it’s increasingly being looked upon as a preventative treatment, not only for cancer, but heart disease, stroke and type 2 diabetes too,” said Shanu Kothari, MD, the president of the ASMBS.

This statement underscores the importance of this study. There may be reluctance to considering any type of surgery a preventative measure. This may be in part responsible for the vast numbers of obese Americans not undergoing bariatric surgery. Reluctance should be met with outreach and education. Obesity is broadly associated with stigma. By adding cancer prevention to the reasons for considering weight reduction surgery we as clinicians have another card to play with patients who may be on the fence about the procedure.

The ASMBS is committed to educating patients and healthcare professionals about the benefits of bariatric surgery. This important task is exemplified by this abstract. By clarifying and quantifying the link between cancer and obesity the authors lend importance to the effort to educate patients struggling with weight management. Hope is just as important as research. The former is made possible by the latter.

References:

1. https://guidebook.com/g/#/guides/am22/lists/1003821/items/14737925
2. Centers for Disease Control and Prevention. (2015) The Health Effects of Overweight and Obesity. Accessed from: https://www.cdc.gov/healthyweight/effects/index.html
3. https://ascopubs.org/doi/full/10.1200/JCO.2014.58.4680