The standard treatment protocol for locally advanced rectal cancer (LARC) typically involves neoadjuvant chemoradiation (nCRT) followed by surgical intervention. Within the realm of LARC treatment, various factors are recognized for their influence on patient survival. Among these factors, tumor regression grade (TRG) remains a subject of ongoing debate. This research endeavor is designed to explore the potential correlations between TRG and the 5-year overall survival (OS) of LARC patients.

A retrospective study was conducted, encompassing a cohort of 124 patients diagnosed with LARC, all of whom underwent nCRT followed by surgery at Tabriz Medical University Hospital during the period spanning 2007 to 2017. A course of chemotherapy utilizing fluoropyrimidines was administered, totaling between 45.0 to 50.4 Gy, delivered in 25 daily fractions. The evaluation of tumor response relied on the modified Ryan TRG classification, with TRG stratified into categories representing total response (TR=TRG0), partial response (PR=TRG1-2), and no response (NR=TRG 3).

The analysis reveals no discernible correlation between TRG and 5-year OS. Specifically, the 5-year OS rates were recorded as 100%, 77%, and 51% for patients exhibiting TR, PR, and NR, respectively (P = 0.53).

This investigation strongly suggests that TRG is unlikely to be a significant determinant of 5-year OS in the context of LARC.