Impact of surgical approach and anastomosis distance on low anterior resection syndrome

INTRODUCTION: Low anterior resection syndrome (LARS) is a frequent functional disorder following sphincter-preserving surgery for rectal cancer. This study aimed to assess the impact of surgical approach and anastomosis distance on LARS development. METHODS: We retrospectively analyzed 115 patients who underwent low anterior resection without diverting stoma between 2012 and 2024. Patients were stratified using the validated LARS score questionnaire. Surgical approaches (open, laparoscopic, robotic) and clinicopathologic features were compared across LARS severity levels. Statistical analysis included Kruskal-Wallis, Mann-Whitney U, chi-square, and Spearman correlation tests. RESULTS: No significant difference in LARS scores was found among open, laparoscopic, and robotic groups (p=0.130), but open surgery showed higher scores compared to minimally invasive surgery (p=0.045). Anastomosis distance ≤4 cm from the anal verge was strongly associated with higher LARS incidence (p<0.001). Other factors, including age, tumor stage, neoadjuvant therapy, and follow-up duration, were not significantly associated with LARS. The most severe symptoms were urgency and clustering. Symptoms plateaued around 4 years postoperatively. CONCLUSION: LARS remains a common complication after rectal cancer surgery. Minimally invasive surgery and anastomosis distance greater than 4 cm from the anal verge were associated with lower LARS scores. Surgical planning should consider functional outcomes in addition to oncologic safety. TRIAL REGISTRATION: This study does not report the results of a clinical trial.