Decision-Linked Multimodal Prediction in Non-Metastatic Rectal Adenocarcinoma

Treatment options for non-metastatic rectal adenocarcinoma include total neoadjuvant therapy, selective radiotherapy omission, watch-and-wait, and mismatch-repair-guided immunotherapy. Prediction studies often conflate pathological and clinical complete response, radiological regression, organ preservation, local regrowth, and survival. This structured narrative review evaluated multimodal assessments by clinical decision and timing. MEDLINE/PubMed, Estudies andcopus were searched for literature published from 1 January 2015 to 30 June 2026, supplemented by guidelines, citation tracking, landmark earlier studies, and separately identified contextual sources. Evidence was organized around baseline selection, restaging, postoperative risk, and surveillance. An author-derived four-tier framework distinguished evidence maturity from implementation feasibility. Baseline pelvic magnetic resonance imaging and mismatch repair/microsatellite instability testing provided the most actionable pretreatment information. Concordant imaging, endoscopy, and digital rectal examination supported clinical complete-response assessment and watch-and-wait only with intensive surveillance and timely salvage surgery. Resection histopathology defined residual disease and postoperative risk but could not retrospectively justify surgery omission. Carcinoembryonic antigen remained an established adjunct. Circulating tumor DNA, radiomics, immune and stromal measures, molecular signatures, and artificial intelligence models require further validation before independently directing treatment. Clinical usefulness depends on alignment with a defined decision, time point, and endpoint. The optimal pathway delivers feasible, validated information when it can safely change care.