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Bariatric Surgery Linked to Lower Cancer Risk in Some Cases
· Confirmed
In Short: The study adds important findings to the literature focused on the link between obesity and cancer, highlighting the potential benefits of bariatric surgery in reducing cancer risk and mortality.
A Cleveland Clinic-led study published in JAMA has found that bariatric surgery can significantly reduce the risk of developing and dying from obesity-related cancers.
Among adults with obesity, those who underwent bariatric surgery experienced a 32% lower incidence of cancer and a 48% lower incidence of mortality due to cancer compared to patients in the nonsurgical control group.
The SPLENDID (Surgical Procedures and Long-term Effectiveness in Neoplastic Disease Incidence and Death) study, which had a median follow-up of 6.1 years, matched 5,053 adult patients who had bariatric surgery between 2004 and 2017 with 25,265 patients who did not have the surgery.
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.
Similarly, 0.8% of patients in the surgery group and 1.4% of patients in the non-surgical group died from cancer.
The study’s lead author, Ali Aminian, MD, noted that patients who undergo bariatric surgery typically lose 20% to 40% of their body weight and sustain it over decades.
Steven Nissen, MD, the study’s senior author, emphasized that obesity is second only to tobacco as a preventable cause of cancer in the United States.
The study also found that the greater the weight loss, the lower the risk of cancer.
However, the study’s authors acknowledged that further research is needed to understand the underlying mechanisms responsible for reduced cancer risk following bariatric surgery.
Amanda Belluzzi, MD, of Ospedale Santa Maria della Misericordia di Rovigo in Rovigo, Italy, and colleagues noted that while bariatric surgery may reduce cancer risk, it should not be offered solely for cancer prevention.
The review found that bariatric surgery was associated with a higher hazard of prostate cancer, though the finding was based on only three studies and requires confirmation.
What this adds
The study highlights the potential benefits of bariatric surgery in reducing cancer risk and mortality, but further research is needed to understand the underlying mechanisms.
What's confirmed
- “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, MD, Chief Academic Officer of Cleveland Clinic’s Heart, Vascular & Thoracic Institute.
- The Cleveland Clinic-led STAMPEDE study showed that following bariatric surgery, significant weight loss and control of type 2 diabetes were durable.
- The SPLENDOR study showed that in patients with fatty liver, bariatric surgery decreases the risk of the progression of liver disease to cirrhosis and serious heart complications.
What's still developing
- 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.
- “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.
- 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.
- Overall, Belluzzi and colleagues rated the certainty of the evidence in their analysis of 26 observational studies as “low or very low.” The review found no randomized clinical trials, and the “risk of bias was judged to be serious for all outcomes, mainly due to the nonrandomized design, potential residual confounding, and selection bias,” the authors wrote.
- But the abstract reported different estimates for breast and endometrial cancer: incidence rate ratios of 0.85 and 0.38, respectively.
- The main text reported pooled adjusted hazard ratios (HRs) of 0.88 for breast, 0.57 for endometrial, and 0.72 for colorectal cancer in favor of surgery.
- Both analyses, however, were based on observational data, limiting conclusions about whether bariatric surgery itself can reduce the risk for cancer.