Near-complete clinical response after neoadjuvant therapy in rectal cancer: Decision-making between organ preservation and surgery

Vollständiger Abstract

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Near-complete clinical response (nCR) after neoadjuvant therapy in rectal cancer represents a clinically relevant but heterogeneous intermediate state between clinical complete response and incomplete clinical response. With the growing adoption of total neoadjuvant therapy, nCR is increasingly encountered; however, its optimal management remains controversial, particularly regarding its definition, timing of assessment, and the balance between organ preservation and oncologic safety. This mini-review synthesizes current evidence regarding the definition of nCR, the associated diagnostic challenges, and multimodal assessment techniques, including endoscopy, magnetic resonance imaging, and clinical examination. Particular emphasis is placed on second restaging, which enables dynamic evaluation of tumor regression and may facilitate conversion to clinical complete response in selected patients. Emerging evidence suggests that nCR comprises two biologically distinct subgroups - favorable and unfavorable - with oncologic risk determined by response trajectory rather than by observation duration alone. Management strategies include continued observation, immediate resection, and, in selected cases, local excision. We propose a practical management algorithm integrating patient preference, response patterns, and restaging findings to guide individualized decision-making. A critical gap remains, as no direct comparisons exist between immediate and delayed resection following persistent nCR. Future studies addressing this question are essential to optimize treatment selection in this challenging population.