Weight Loss with Bariatric Surgery Cuts the Risk of Developing Cancer and Death from Cancer

SPLENDID study adds important findings to research on obesity and cancer

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A Cleveland Clinic study shows that among adults with obesity, weight loss achieved with bariatric surgery was associated with a 32% lower risk of developing cancer and a 48% lower risk of cancer-related death compared with adults who did not have the surgery. The research is published in JAMA.

Approximately 42% of American adults have obesity, according to the Centers for Disease Control and Prevention (CDC). Obesity increases the risk of developing 13 types of cancer that account for 40% of all cancers diagnosed every year in the United States, according to the CDC.

Ali Aminian, M.D., lead author of the study and director of Cleveland Clinic’s Bariatric & Metabolic Institute, said that bariatric surgery is currently the most effective treatment for obesity. “Patients can lose 20 to 40% of their body weight after surgery, and weight loss can be sustained over decades. The striking findings of this study indicate that the greater the weight loss, the lower the risk of cancer,” said Dr. Aminian.

The SPLENDID (Surgical Procedures and Long-term Effectiveness in Neoplastic Disease Incidence and Death) research is a matched-cohort study that included more than 30,000 Cleveland Clinic patients. A group of 5,053 adult patients with obesity who had bariatric surgery between 2004 and 2017 were matched 1:5 to a control group of 25,265 patients who did not have surgery for their obesity.

After 10 years, 2.9% of patients in the bariatric surgery group and 4.9% of patients in the non-surgical group developed an obesity-associated cancer.  The International Agency for Research on Cancer describes 13 types of cancer as obesity-associated cancers such as endometrial cancer, postmenopausal breast cancer, and cancers of the colon, liver, pancreas, ovary and thyroid.

After 10 years, 0.8% of patients in the surgery group and 1.4% of patients in the non-surgical group died from cancer. Those findings indicate that bariatric surgery is associated with a 48% lower risk of dying from cancer.

Researchers noted that the benefits of bariatric surgery were seen in a wide range of study participants, including both women and men, young and old, and Black and white patients. In addition, benefits were similarly observed after both gastric bypass and gastric sleeve operations.

“According to the American Cancer Society, obesity is second only to tobacco as a preventable cause of cancer in the United States,” said the study’s senior author, Steven Nissen, M.D., Chief Academic Officer of the Heart, Vascular and Thoracic Institute. “This study provides the best possible evidence on the value of intentional weight loss to reduce cancer risk and mortality.” 

Numerous studies have shown the health benefits of bariatric or weight-loss surgery in patients with obesity. The Cleveland Clinic-led STAMPEDE study showed that following bariatric surgery, significant weight loss and control of type 2 diabetes last over time. The SPLENDOR study showed that in patients with fatty liver, bariatric surgery decreases the risk of the progression of liver disease and serious heart complications.

The SPLENDID study adds important findings to the literature focused on the link between obesity and cancer. Given the growing epidemic of obesity worldwide, these findings have considerable public health implications.

“Based on the magnitude of benefit shown in our study, weight loss surgery can be considered in addition to other interventions that can help prevent cancer and reduce mortality,” said Jame Abraham, M.D., chairman of the Hematology and Medical Oncology Department at Cleveland Clinic. “Further research needs to be done to understand the underlying mechanisms responsible for reduced cancer risk following bariatric surgery.”

About Cleveland Clinic
Cleveland Clinic is a nonprofit multispecialty academic medical center that integrates clinical and hospital care with research and education. Located in Cleveland, Ohio, it was founded in 1921 by four renowned physicians with a vision of providing outstanding patient care based upon the principles of cooperation, compassion and innovation. Cleveland Clinic has pioneered many medical breakthroughs, including coronary artery bypass surgery and the first face transplant in the United States. U.S. News & World Report consistently names Cleveland Clinic as one of the nation’s best hospitals in its annual “America’s Best Hospitals” survey. Among Cleveland Clinic’s 72,500 employees worldwide are more than 5,050 salaried physicians and researchers, and 17,800 registered nurses and advanced practice providers, representing 140 medical specialties and subspecialties. Cleveland Clinic is a 6,500-bed health system that includes a 173-acre main campus near downtown Cleveland, 21 hospitals, more than 220 outpatient facilities, including locations in northeast Ohio; southeast Florida; Las Vegas, Nevada; Toronto, Canada; Abu Dhabi, UAE; and London, England. In 2021, there were 10.2 million total outpatient visits, 304,000 hospital admissions and observations, and 259,000 surgical cases throughout Cleveland Clinic’s health system. Patients came for treatment from every state and 185 countries. Visit us at clevelandclinic.org. Follow us at twitter.com/ClevelandClinic. News and resources available at newsroom.clevelandclinic.org.

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