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Bariatric surgery may reduce the risk of colorectal cancer

Wed, 01/29/2020 - 09:12
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Bariatric surgery may reduce the risk of developing colorectal cancer by one-third, according to a researchers from Kuwait who carried out a meta‐analysis to investigating the effect of bariatric surgery on the risk of developing colorectal cancer in obese individuals.

The study, ‘Role of bariatric surgery in reducing the risk of colorectal cancer: a meta-analysis’, published in the British Journal of Surgery, found that the overall risk of developing colorectal cancer was three in 1,000 in patients with obesity who underwent bariatric surgery, compared with four in 1,000 in those who did not.

"Day by day, the scientific community is continuing to uncover the benefits of weight loss surgery, and this paper affirms this," said lead author, Dr Sulaiman Almazeedi of Jaber Al-Ahmed Hospital, in Kuwait. "Obesity today remains one of the most preventable causes of morbid disease and early death, and despite the controversy, we believe weight loss surgery can be an important tool in tackling this epidemic."

It is known that obesity increases the risk of many conditions, including type 2 diabetes, cardiovascular diseases and most cancers, including colorectal cancer. This latest BJS analysis was conducted because individual studies have presented conflicting results. The paper included seven studies with a total of 1,213,727 patients who had undergone sleeve gastrectomy, RYGB, gastric banding and duodenal switch, thereby increasing the generalisability and relevance of the findings. The average follow-up was seven years.

The pooled estimate of the RR was 0.64 (95 per cent CI 0.42 to 0.98) and a test of asymmetry found no significant publication bias. Meta‐regression showed that sample size was a statistically significant factor (p=0.037), but year of publication, region and mean duration of follow‐up were not significant.  The authors noted that patients who underwent bariatric surgery had a greater than 35 per cent reduction in the risk of developing colorectal cancer, compared with obese individuals who had no surgery.

Although the authors wanted to assess the differences in incidence between colonic and rectal cancer, the effect of surgery on long-term follow-up and patient-specific factors such as age and, the papers did not have the data for such analysis and so these questions remain to be answered in the future.

The researchers also noted that future studies should examine the difference in the incidence of colorectal cancer from different procedures (restrictive vs malabsorptive or RYGB vs s LSG) to help develop a more patient-tailored approach to the treatment of obesity in the future.

“In addition to the numerous benefits of bariatric surgery, such as a reduction in the risk of diabetes, cardiovascular, respiratory and musculoskeletal diseases, patients also gain a significant reduction in the risk of colorectal cancer,” however, the authors caution, “Unfortunately, owing to the nature of the data in the studies included in the meta-analysis, definitive conclusions could not be drawn regarding the specific relationship between RYGB and rectal cancer. This risk needs further investigation in higher-quality studies.”

This data was also presented at the XXIV World Congress of the International Federation for the Surgery of Obesity and Metabolic Disorders, Madrid, Spain, September 2019.