Major low anterior resection syndrome and fecal incontinence after ileostomy reversal following hand-sewn intersphincteric resection for low and ultralow rectal cancer.

BACKGROUND: Functional morbidity remains an important survivorship concern after sphincter-preserving surgery for very low rectal cancer. We evaluated factors associated with major low anterior resection syndrome (LARS) and fecal incontinence after ileostomy reversal following hand-sewn intersphincteric resection (ISR). METHODS: This retrospective cohort study included consecutive patients who underwent hand-sewn ISR with coloanal anastomosis and diverting ileostomy for low or ultralow rectal cancer at two tertiary centers between 2019 and 2024. Functional outcomes were assessed 12-15 months after ileostomy reversal using the LARS score and Wexner Fecal Incontinence Score. Major LARS was defined as a LARS score ≥30, and fecal incontinence severity was assessed using the Wexner score. Modified Poisson regression was used for major LARS, and multivariable linear regression with robust standard errors was used for Wexner score. RESULTS: Major LARS occurred in 61 of 128 patients (47.7%). The median LARS and Wexner scores were 29.0 (IQR, 20.0-34.0) and 9.0 (IQR, 6.0-11.2), respectively. Patients with major LARS had higher Wexner scores than those with no/minor LARS (12.0 vs 6.0; P < 0.001). In the adjusted major-LARS model, shorter tumor distance from the anal verge, neoadjuvant chemoradiotherapy (nCRT), and female sex were associated with major LARS. In adjusted Wexner regression, shorter tumor distance from the anal verge and nCRT were associated with higher Wexner scores. CONCLUSIONS: Major LARS was common, and continence impairment was observed after ileostomy reversal following hand-sewn ISR. Shorter tumor distance from the anal verge and nCRT showed consistent associations across major LARS and Wexner score outcomes.