Colorectal Surgery

Higher BMI reduces adjuvant dose intensity and may indirectly worsen CRC survival.

In an IPD meta-analysis of four adjuvant trials (n=7264), each 5 kg/m2 higher BMI associated with -1.15% cumulative relative dose (95% CI -1.92, -0.38). Higher ACRD was linked to better overall survival (HR 0.94 per 5% ACRD, 95% CI 0.91-0.96). BMI was not associated with grade 3+ toxicity, suggesting dose reductions reflect treatment-selection rather than excess toxicity. Authors conclude obesity may have an adverse indirect effect on survival via reduced adjuvant dosing, supporting full BSA-based dosing. 1

Bacterial, but not fungal, gut diversity declines after colorectal surgery.

Prospective cohort of 59 patients showed significant postoperative decrease in bacterial alpha diversity (Shannon p<0.001). Postoperative bacterial communities displayed greater inter-patient variability (PERMANOVA p=0.001). Fungal alpha diversity did not change significantly after surgery (p>0.05). Preoperative bacterial–fungal network analysis identified 18 clusters with distinct metabolic pathway enrichments. 2

Advanced serrated lesions confer substantial long-term CRC risk after polypectomy.

In COLONPREV (n=8989) with mean 9.5 years follow-up, 10-year cumulative CRC incidence was 1.09% for ASL and 1.23% for advanced adenomas. Multivariable HR for CRC was increased with ASL (HR 6.37, 95% CI 1.42-28.54) and advanced adenomas (HR 9.77, 95% CI 4.24-22.50). Surveillance colonoscopy associated with lower CRC incidence (one colonoscopy HR 0.46; ≥2 HR 0.09). Authors recommend risk-stratified post-polypectomy surveillance that includes ASL as high-risk lesions. 3