Clinical Management of Low Anterior Resection Syndrome: Review of the Current Diagnosis and Treatment

SIMPLE SUMMARY: Low anterior resection syndrome (LARS) significantly impacts the lives of 80% of patients who undergo sphincter-preserving surgery, often leading to diminished quality of life and social avoidance. However, a lack of systematic standards and varied measurement and treatment approaches have hindered optimal management and understanding of LARS. This study seeks to synthesize findings from up until 2023 and establish unified diagnostic criteria and management protocols to facilitate seamless integration of findings from specifical clinical trials into clinical application. The aim is to enable comparable research outcomes and enhance clinical methodologies, potentially offering a coherent framework that could shape future research directions and improve clinical outcomes in LARS management. We proposed that in clinical treatment, the severity of LARS should be assessed using at least one symptom assessment questionnaire and one scale related to quality of life. In clinical trials, a new criterion including the LARS score, EORTC QLQC30, and anorectal manometry is suggested to be adopted by following the research. A stepwise classification model was set up for the standardized clinical management of LARS. ABSTRACT: Background: Low anterior resection syndrome (LARS) is a series of bowel dysfunction symptoms, including altered bowel frequency, irregular bowel rhythms, fecal incontinence, and constipation. LARS occurs in 80% of patients undergoing sphincter-preserving surgery, affecting patients’ quality of life along with social avoidance. Different measurements and treatments have been raised to deal with LARS, but no systematic standard has been developed. Objective and Methods: To promote the standardization of clinical trials and clinical management of LARS, this review summarizes the latest findings up until 2023 regarding the diagnostic criteria, assessment protocols, and treatment modalities for postoperative LARS in rectal cancer. Results: The diagnostic criteria for LARS need to be updated to the definition proposed by the LARS International Collaborative Group, replacing the current application of the LARS score. In both clinical trials and clinical treatment, the severity of LARS should be assessed using at least one symptom assessment questionnaire, the LARS score or MSKCC BFI, and at least one scale related to quality of life. Anorectal manometry, fecoflowmetry, endoscopic ultrasonography, and pelvic floor muscle strength testing are recommended to be adopted only in clinical trials. After analysis of the latest literature on LARS treatment, a stepwise classification model is established for the standardized clinical management of LARS. Patients with minor LARS can start with first-line treatment, including management of self-behavior with an emphasis on diet modification and medication. Lamosetron, colesevelam hydrochloride, and loperamide are common antidiarrheal agents. Second-line management indicates multi-mode pelvic floor rehabilitation and transanal irrigation. Patients with major LARS should select single or several treatments in second-line management. Refractory LARS can choose antegrade enema, neuromodulation, or colostomy. Conclusions: In clinical trials of LARS treatment between 2020 and 2022, the eligibility criteria and evaluation system have been variable. Therefore, it is urgent to create a standard for the diagnosis, assessment, and treatment of LARS. Failure to set placebos and differentiate subgroups are limitations of many current LARS studies. Randomized controlled trials comparing diverse therapies and long-term outcomes are absent, as well. Moreover, a new scale needs to be developed to incorporate the patient’s perspective and facilitate outpatient follow-up. Though the establishment of a stepwise classification model for LARS treatment here is indispensable, the refinement of the guidelines may be improved by more standardized studies.