Efficacy and safety of the traditional Chinese medicine formulation BL-1 for the treatment of low anterior resection syndrome: study protocol for a double-blind, randomized, placebo-controlled trial.

Objective: Low anterior resection syndrome (LARS), a prevalent sequela following rectal cancer surgery, poses a substantial burden on patients' quality of life (QOL), daily functioning, and psychological well-being, and its management remains an unmet clinical need due to the absence of specific therapeutic agents. Although traditional Chinese medicine (TCM) shows promise in supporting postoperative gastrointestinal recovery, high-quality evidence for its application in LARS is lacking. This trial is designed to assess the efficacy and safety of the investigational TCM formulation BL-1 in patients with LARS. Methods/design: The study will be conducted as a randomized, double-blind, placebo-controlled trial, comprising a 4-week intervention phase and a subsequent 2-week follow-up period. A total of 234 patients with LARS, aged 18 to 75 years, are planned to be enrolled in this study. Eligible participants will be randomized to receive either the BL-1 group or placebo group in a 1:1 ratio. Participants in the experimental group will receive BL-1 formulation, whereas those in the placebo group will receive an indistinguishable BL-1 placebo. The primary outcome measure is the change in LARS score from baseline to week 4. Secondary outcome measures encompass: (a) stool frequency and consistency (assessed via the Bristol Stool Scale); (b) severity of fecal incontinence (evaluated using the Wexner Anal Incontinence Scale); (c) QOL, measured with the European Organization for Research and Treatment of Cancer QOL questionnaire and the Karnofsky Performance Status score; and (d) other patient-reported outcomes. Safety will be monitored continuously throughout the treatment, with assessments including the incidence of adverse events and laboratory abnormalities. Discussion: BL-1 is the compound prescription of eleven traditional Chinese medicinal materials: Bupleuri Herba, Ginseng Radix et Rhizoma, Astragali Radix, Atractylodis Macrocephalae Rhizoma, Cimicifugae Rhizoma, Mume Fructus, and Aconiti Lateralis Radix Praeparata (patent number ZL 2024 1 1479878.8). In recent years, BL-1 has been applied to treat digestive system diseases, particularly defecation disorders, and may offer potential benefits for adults with LARS. The absence of robust clinical evidence has prompted the design of this randomized, double-blind, placebo-controlled trial to rigorously evaluate its therapeutic efficacy and safety. This trial is expected to yield critical data that will inform the clinical use of BL-1 formulation in the management of LARS. Ethics and dissemination: Ethical approval for this study was obtained from the Ethics Committee of West China Hospital, Sichuan University (Approval ID: 20241218). All participants must provide written informed consent before randomization. Subsequently, the trial results will be submitted for publication in a peer-reviewed academic journal. Clinical trial registration: https://www.chictr.org.cn, identifier ChiCTR2400087108.