Background: A fundamental understanding of the impact of bariatric surgery (BRS) on mechanisms of colorectal carcinogenesis is limited. For instance, studies report a reduced risk of colorectal cancer in females but not in males after BRS. We examined whether this sex-specific difference existed at the earlier polyp development stage. Methods: This retrospective cohort study included 281,417 adults from the 2012–2020 MarketScan database. We compared polyps rates on colonoscopy in four groups: post- vs. pre-BRS (treatment) to post- vs. pre-severe obesity (SO) diagnosis (control). We focused our main analysis on a propensity-matched sample that yielded a balanced distribution of covariates in our four groups (n= 9680 adults, 21.9% males). We also adjusted for important covariates. Results: Metabolic syndrome parameters improved after bariatric surgery and worsened after severe obesity diagnosis (p< 0.05). The rate of polyps was 46.7% at a median of 0.5 years pre-BRS and 47.9% at a median of 0.6 years pre-SO diagnosis. The polyps rate was 45.4% at a median (range) of 3.2 (1.0–8.5) years post-BRS. Conversely, 53.8% of adults had polyps at 3.0 (1.0–8.6) years post-SO. There was no change in the risk of colorectal polyps in males or females post- vs. pre-BRS. However, the risk of polyps was higher in males (OR = 1.32, 95% CI: 1.02–1.70) and females (OR = 1.29, 95% CI: 1.13–1.47) post- vs. pre-SO. When compared to the control group (SO), the odds ratios for colorectal polyps were lower for males and females after bariatric surgery (OR = 0.63, 95% CI: 0.44–0.90, and OR = 0.79, 95% CI: 0.66–0.96, respectively). Conclusions: Obesity is associated with an increased risk of colorectal polyps, an effect that is ameliorated after bariatric surgery. These data are relevant for studies investigating colorectal carcinogenesis mechanisms.
背景：目前对减重手术影响结直肠癌发生机制的基础认识尚有限。例如，有研究报道减重手术后女性结直肠癌风险降低，但男性未见此效应。本研究旨在探究这种性别特异性差异是否在更早期的息肉发展阶段即已存在。方法：本回顾性队列研究纳入2012–2020年MarketScan数据库中的281,417名成人。我们通过比较四组人群的结肠镜息肉检出率进行分析：减重手术前后（治疗组）与重度肥胖诊断前后（对照组）。主要分析聚焦于经倾向评分匹配的样本，该样本使四组协变量分布均衡（n=9680名成人，男性占21.9%），并对重要协变量进行了校正。结果：减重手术后代谢综合征参数改善，而重度肥胖诊断后参数恶化（p<0.05）。减重手术前中位0.5年的息肉检出率为46.7%，重度肥胖诊断前中位0.6年为47.9%。减重手术后中位3.2年（范围1.0–8.5年）的息肉检出率为45.4%；相反，重度肥胖诊断后3.0年（1.0–8.6年）的息肉检出率达53.8%。无论男性或女性，减重手术前后结直肠息肉风险均无变化。然而，与诊断前相比，重度肥胖诊断后男性（OR=1.32，95% CI：1.02–1.70）和女性（OR=1.29，95% CI：1.13–1.47）的息肉风险均升高。与对照组（重度肥胖）相比，减重手术后男性和女性结直肠息肉的比值比均降低（OR分别为0.63，95% CI：0.44–0.90和0.79，95% CI：0.66–0.96）。结论：肥胖与结直肠息肉风险增加相关，而减重手术可改善此效应。这些数据对探究结直肠癌发生机制的研究具有参考价值。
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