Understanding Low Anterior Resection Syndrome (LARS) in Rectal Surgery: Prevalence, Risk Factors, and Implications for Surgical Practice

Low Anterior Resection Syndrome (LARS) is a common, high‑impact complication after sphincter‑preserving rectal resection that substantially reduces postoperative quality of life. This multicenter analysis reframes expected outcomes: when a standardized consensus definition and systematic sampling are used, LARS prevalence is markedly higher than earlier estimates.

Smaller series previously reported lower rates, but this larger, multicenter dataset—applying uniform definitions and systematic sampling—reveals a substantially greater burden of postoperative dysfunction across diverse centers. The finding pushes expected LARS rates upward for routine counseling and outcome benchmarking.

In a multicenter, cross‑sectional survey of patients treated with curative rectal resection, 343 respondents were evaluated using the international consensus definition as the primary endpoint. A one‑time questionnaire was administered across ten institutions with robust response rates. The study identified a 72.5% prevalence under that consensus definition, with consistent results across follow‑up intervals and clear symptom patterns captured by the standardized tool. These multicenter data indicate that consensus‑based assessment detects LARS in the majority of patients after anterior resection; prevalence estimates for quality metrics and patient counseling should therefore align with the consensus definition to avoid systematic undercounting.

Multivariable analysis flagged younger age and lower anastomotic level as independent predictors of LARS, with odds ratios indicating clinically meaningful risk increases for patients under 70 years and for anastomoses located at or below roughly 5 cm. Symptoms defined by the consensus instrument included urgency, increased stool frequency, fecal incontinence, clustering of stools, and emptying difficulties. These associations persisted after adjustment for tumor and treatment factors and warrant explicit discussion during preoperative counseling and intraoperative planning.

Next steps include adopting the consensus definition for institutional audits, refining preoperative risk stratification, and prioritizing targeted interventions and trials to mitigate LARS.

Key Takeaways:

• Using the consensus definition, LARS occurs in roughly three‑quarters of patients—substantially higher than prior small‑series estimates.
• All patients after anterior resection remain at risk; younger patients and those with lower anastomoses are disproportionately impacted.
• Institutions should integrate consensus‑based screening into follow‑up, incorporate LARS risk into diversion and anastomotic strategy discussions, and set realistic recovery expectations at consent.