The Longitudinal Course of Low-Anterior Resection Syndrome: An Individual Patient Meta-Analysis

Background: Low anterior resection syndrome (LARS) describes disordered bowel function after rectal resection that significantly impacts quality of life. However, the current understanding of the longitudinal course of LARS is insufficient to guide patient expectations or identify those at risk of persisting dysfunction.Methods: 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 two or more post-operative time points. De-identified patient-level data were requested from study authors. Baseline LARS scores were taken from 3- or 6-month assessments. Regression analyses were undertaken to identify independent predictors of change in LARS score from baseline to 12-months and 18-24-months.Findings: Eight studies with a total of 701 eligible patients were included. The mean LARS score improved over time, from 29.4 (95% CI 28.6 – 30.1) at baseline to 16.6 at 36 months (95% CI 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 PME vs TME (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).Interpretation: LARS improves by 18 months postoperatively then remains relatively stable for up to 3 years. TME, neoadjuvant radiotherapy, and ileostomy formation negatively impact upon bowel function recovery. These data will aid perioperative decision making by helping to inform patient and clinician expectations of functional outcome after rectal resection.Funding Information: New Zealand Health Research Council, Royal Australasian College of Surgeons, Maurice and Phyllis Paykel Trust .Declaration of Interests: Professor Greg O’Grady and Professor Ian P. Bissett are members of The University of Auckland Spin-out companies: The Insides Company Ltd (GOG, IPB), and Alimetry Ltd (GOG). All other authors have nothing to declare.