Published online Apr 28, 2026. doi: 10.3748/wjg.v32.i16.116405
Revised: January 20, 2026
Accepted: February 10, 2026
Published online: April 28, 2026
Processing time: 157 Days and 13.3 Hours
Low anterior resection syndrome (LARS) severely compromises patients’ quality of life after sphincter-preserving surgery for rectal cancer. Although the etiology of LARS is multifactorial, the tumor location is considered a primary determinant, as it directly governs the height of the surgical anastomosis. However, it remains unclear whether the initial functional deficit and the subsequent long-term recovery trajectory differ according to the tumor height. The longitudinal evo
To compare the postoperative features and longitudinal recovery trajectories of LARS between patients with ultra-low and non-ultra-low rectal cancer.
In this single-center prospective cohort study (June 2018 to January 2024), patients undergoing sphincter-preserving surgery were stratified into ultra-low (≤ 3 cm from the dentate line) and non-ultra-low (> 3 cm) tumor groups. LARS scores were systematically collected via follow-up at 1-, 3-, 6-, 9-, and 12-month postoperatively. After propensity score matching, A generalized estimating equation (GEE) model was used to model the longitudinal LARS data, assessing the effects of group, time, and their interaction while accounting for repeated measures.
The final analysis included a matched cohort of 220 patients (110 per group). At all postoperative follow-up points, the ultra-low group demonstrated a significantly higher incidence of LARS (e.g., 1 month, 75.5% vs 51.8%; 12 months, 30.0% vs 14.5%; all P < 0.05). Longitudinal GEE modeling confirmed that an ultra-low tumor location was associated with a persistently higher overall odds of LARS throughout the first year (OR = 2.858, 95%CI = 1.611-5.070; P < 0.001). A significant time effect (P < 0.001) signaled functional improvement in both cohorts. Critically, the non-significant group-by-time interaction (P = 0.900) revealed that the groups followed parallel recovery trajectories.
All patients exhibited improved gastrointestinal function over the first year, but those with ultra-low tumors had significantly worse baseline function and persistently higher LARS risk, underscoring the need for tailored management.
Core Tip: Parallel recovery trajectory: After propensity score matching, the ultra-low and non-ultra-low rectal cancer groups shared a similar rate of functional improvement throughout the first postoperative year. Persistently higher risk: Despite the similar recovery pace, the ultra-low group consistently faced a significantly higher overall risk of low anterior resection syndrome (LARS), attributable to a worse initial functional baseline. Clinical implication: These findings establish tumor height as a critical, independent determinant of LARS, underscoring the need for tailored counseling and proactive management strategies for patients with ultra-low tumors.