Predictive Risk Factors for Low Anterior Resection Syndrome (LARS) in Rectal Cancer—An Observational Cohort Study

<b>Background/Objectives</b>: The improved long-term survival of rectal cancer patients has led to a major increase in the prevalence of functional complications. Understanding which patients are prone to develop major LARS is important for their preoperative counselling and follow-up. Herein, we aimed to assess the risk factors for LARS. <b>Methods</b>: This is a retrospective cohort study on rectal cancer patients. All patient and tumour variables, management plan, type of neoadjuvant therapy, radiation dose to anal sphincter, and perioperative outcomes were collected from the hospital electronic databases. We quantified LARS and compared the score before and after surgery (mean follow-up of 42.2 ± 32 months). <b>Results</b>: A total of 182 patients were included for the final analysis. LARS was present in 43.4% (n = 79) of patients, with 14.8% (n = 27) having minor LARS and 28.5% (n = 52) having major LARS. Age (<i>p</i> = 0.03), male gender (<i>p</i> < 0.00001), smoking (<i>p</i> = 0.04), neoadjuvant radiotherapy (<i>p</i> = 0.02), rectal stump length (<i>p</i> = 0.008), end-to-end anastomosis (<i>p</i> = 0.008), and ileostomy (<i>p</i> = 0.002) were found to significantly increase the rate of LARS. A logistic regression model based on the above variables was able to predict major LARS with good predictive value (AUC 0.700). <b>Conclusions</b>: LARS is highly common after sphincter-preserving surgery, and it is significantly more common in young, male patients with a history of smoking, having mid-lower rectal cancers with neoadjuvant radiotherapy, and undergoing TME surgery with end-to-end low anastomosis and ileostomy.