Bariatric surgery has the potential role in reducing future colorectal cancer (CRC) in patients with obesity at a population level, according to a current systematic review and meta-analysis by researchers from Ireland. Their findings noted that gastric bypass and sleeve provided the greatest reduction in CRC risk.
The study authors stated that the estimated obesity-related risk of CRC increases by 24% in male patients and 9% in female patients with every 5 kg/m2 increase in body mass index (BMI). However, 22 year outcomes from the Swedish Obese Subjects (SOS) study showed a similar CRC risk in patients with obesity whether they had undergone bariatric surgery or not.
Therefore, the researchers performed a systematic review and meta-analysis to determine the value of performing bariatric surgery in reducing CRC risk in patients with obesity using only registry data. They identified data from 11 registries (6,214,682 patients) of which six provided registry data in relation to CRC risk following bariatric surgery in the USA. The type of bariatric surgery, either laparoscopic gastric bypass surgery (GB), laparoscopic adjustable gastric banding (LAGB) or laparoscopic sleeve gastrectomy (SG), was outlined in ten of the included studies.
In total, 14.0% underwent bariatric surgery (872,499/6,214,682) and 86.0% did not undergo bariatric surgery (5,432,183/6,214,682) with nine studies published follow-up data (mean follow-up was 5.1 year). Overall, the researchers found patients with obesity who underwent bariatric surgery were less likely to develop CRC than their counterparts (p<0.001). In total, 0.6% of patients with obesity who underwent bariatric surgery later developed CRC (4843/872,499), compared with 1.0% of patients with obesity who did not undergo bariatric surgery and later developed CRC (54,721/5,432,183).
Four studies provided data for inclusion in Bayesian network meta-analyses (NMA), which included data in relation to 1,476,151 patients with obesity, of whom 88.3% did not undergo surgery, 2.5% underwent LAGB (35,247/1,476,151), 4.6% underwent SG (67,387/1,476,151) and 4.6% underwent GB (68,477/1,476,151).
They reported that:
Those who did not undergo surgery, 1.1% developed CRC (14,018/1,304,050)
Patient who had LAGB, 0.5% developed CRC (185/36,237)
Patient who had SG, 0.4% developed CRC (253/67,387)
Patient who had GB, 0.3% developed CRC (236/68,477) (p<0.001)
At NMA, patients with obesity undergoing GB and SG were less likely to develop CRC than those who did not undergo bariatric surgery
“Patient counselling and shared decision-making ab initio of their bariatric surgery should include this data on CRC incidence in conjunction with the other important health implications of bariatric surgery,” they concluded.
The findings were published in the paper, ‘The Impact of Bariatric Surgery on the Incidence of Colorectal Cancer in Patients with Obesity—a Systematic Review and Meta-analysis of Registry Data’, published in Obesity Surgery. To access this paper, please click here