The Longitudinal Course of Low-anterior Resection Syndrome

We aimed to better understand the longitudinal course of low anterior resection syndrome (LARS) to guide patient expectations and identify those at risk of persisting dysfunction.LARS describes disordered bowel function after rectal resection that significantly impacts quality of life.MEDLINE, EMBASE, CENTRAL, and CINAHL databases were systematically searched for studies that enrolled adults undergoing anterior resection for rectal cancer and used the LARS score to assess bowel function at ≥2 postoperative time points. Regression analyses were performed on deidentified patient-level data to identify predictors of change in LARS score from baseline (3-6months) to 12-months and 18-24 months.Eight studies with a total of 701 eligible patients were included. The mean LARS score improved over time, from 29.4 (95% confidence interval 28.6-30.1) at baseline to 16.6 at 36 months (95% confidence interval 14.2%-18.9%). On multivariable analysis, a greater improvement in mean LARS score between baseline and 12 months was associated with no ileostomy formation [mean difference (MD) -1.7 vs 1.7, P < 0.001], and presence of LARS (major vs minor vs no LARS) at baseline (MD -3.8 vs -1.7 vs 5.4, P < 0.001). Greater improvement in mean LARS score between baseline and 18-24 months was associated with partial mesorectal excision vs total mesorectal excision (MD-8.6 vs 1.5, P < 0.001) and presence of LARS (major vs minor vs no LARS) at baseline (MD -8.8 vs -5.3 vs 3.4, P < 0.001).LARS improves by 18 months postoperatively then remains stable for up to 3 years. Total mesorectal excision, neoadjuvant radiotherapy, and ileostomy formation negatively impact upon bowel function recovery.