Pathological Response Depth and Pre-Treatment Risk Stratification After Neoadjuvant Chemoradiotherapy for Rectal Cancer

Background and Objectives: Neoadjuvant chemoradiotherapy (nCRT) is standard care for locally advanced rectal cancer, yet whether benefit derives from treatment receipt or from response depth remains debated. We examined nCRT receipt and tumour regression against outcome, and whether poor response is predictable beforehand. Materials and Methods: Eighty-nine consecutive patients undergoing resection for rectal or rectosigmoid adenocarcinoma (2020–2022; median follow-up 16 months) were analysed; outcomes were described in patients receiving nCRT (n = 60) and in those undergoing upfront surgery (n = 29), two groups whose allocation depended on stage and location and which are therefore presented as distinct clinical populations rather than as directly comparable arms. Response was graded by modified Ryan tumour regression grade. An exploratory four-item Pre-treatment Response Risk (PRR) score was derived and internally validated by bootstrap optimism correction. Comparisons used the Student t-test or Mann–Whitney U test and the chi-square or Fisher exact test, with logistic (maximum likelihood and Firth-penalised) and Cox regression and receiver operating characteristic analyses.