Pelvic index/mesorectal length ratio: a new predictive factor for rectal cancer prognosis and low anterior resection syndrome

Objective: This study aimed to evaluate whether the pelvic index/mesorectal length (PI/ML) ratio is an effective factor in recurrence, anastomotic leakage, mesorectal excision status, and low anterior resection syndrome (LARS) development in rectal cancer patients undergoing total mesorectal excision.Methods: A total of 47 patients who underwent surgery for rectal cancer between January 2016 and December 2021 were included.Demographics, clinical data, and pre-operative PI measurements were recorded.Post-operative LARS was assessed using the LARS questionnaire in patients followed for at least 12 months.Results: A significant association was found between PI/ML ratio and tumor recurrence (p < 0.0001).Receiver operating characteristic analysis identified a cutoff value of PI/ML < 1.6 for predicting tumor recurrence, with 100% sensitivity and 84.6% specificity.After applying Bonferroni correction for multiple comparisons (n = 4, adjusted significance threshold p < 0.0125), this association remained statistically significant.The association between PI/ML ratio and anastomotic leakage (cutoff < 2.15; sensitivity 100%, specificity 53.7%) showed marginal significance (p = 0.009).No significant association was found between PI/ML ratio and LARS or mesorectal excision status after correction.Conclusions: PI/ML ratio appears to be a useful predictor for tumor recurrence and may help identify patients at risk for anastomotic leakage in rectal cancer surgery.However, this ratio was not significantly associated with the development of LARS.Further research with larger cohorts is needed to validate these findings and clarify the potential prognostic value of the ratio.