Effect of leukotriene receptor antagonists on rectal aberrant crypt foci as indicators of risk of colorectal cancer development: A single-center non-randomized controlled trial

Background and Aim: Aberrant crypt foci (ACF) in the rectum have been reported to correlate with the risk of colorectal tumorigenesis and are useful biomarkers for predicting the risk of colorectal cancer because they are quantitative and can be evaluated in a short period of time. Leukotriene receptor antagonists (LTRAs) have been reported to have inhibitory effects on various carcinomas, but their effects on colorectal cancer are unknown. Based on the report that colorectal cancer overexpresses the cysteinyl leukotriene receptor, we investigated whether LTRA medication affects the number of ACF. Methods: The eligibility criteria were patients who were between 30 and 80 years old, had colorectal tumors that were suitable for endoscopic resection, and had at least five ACFs in the rectum. First, 30 patients were enrolled in the LTRA group, who were treated with montelukast sodium 10 mg for 8 weeks, and rectal ACFs were counted during treatment of colorectal tumors. 10 patients in the no medication follow-up group were enrolled as the control group. Results: One patient in the control group was not examined due to the COVID-19 pandemic, so we examined 30 patients in the LTRA group and 9 patients in the control group. The number of rectal ACFs decreased to -2.4 (SD 2.2) in the LTRA group compared to baseline, while there was no decrease to 0.4 (SD 2.3) in the control group, and there was a significant difference in ACF trends between the two groups (P = 0.002). The Ki67 labeling index, which is a cell proliferation activity, was -1.34 (SD 2.68) in the LTRA group compared to baseline, while it was 0.13 (SD 1.89) in the control group, but there was no significant difference between the two groups. Conclusion: The LTRA treatment decreased rectal ACF and may reduce the risk of colorectal cancer.