A 2-year prospective study on the evolution of Low Anterior Resection Syndrome (LARS) following rectal cancer surgery.

PURPOSE: This study investigated the evolution of Low Anterior Resection Syndrome (LARS) over 2 years following Total Mesorectal Excision (TME) for rectal cancer. METHODS: In this prospective cohort study, patients were recruited from three Belgian hospitals between January 2017 and January 2021. The primary outcome was the evolution of LARS, assessed with the LARS score at 1, 6, 12, and 24 months postoperatively or after stoma closure. The proportion of patients in each LARS category (no, minor, major) was analyzed, and transitions over time were examined using Bowker's test of symmetry. The secondary outcome was health-related quality of life, measured using the Short Form-12 (SF-12) at the same time points. RESULTS: Of 180 patients who underwent TME for rectal cancer, 87 (48.3%) completed the LARS score at all time points. At 1 month postoperatively, 66 patients (75.9%) had major LARS, decreasing to 51 patients (58.6%) at 6 months (p = 0.028). No significant changes were observed thereafter (p = 0.43 and p = 0.45 for 6 to 12 months and 12-24 months, respectively). Among the 51 patients with major LARS at 6 months, 10 patients (20%) improved by 12 and 24 months. Between 1 month and later time points, approximately 60% remained in the same category, 30% improved, and 10% deteriorated. Mean SF-12 physical and mental scores were similar across LARS categories at all time points. CONCLUSION: The majority of spontaneous improvement in LARS occurred within the first 6 months postoperatively, with little improvement thereafter. These findings highlight the need for early proactive management rather than expectant follow-up.