[Advances in systemic therapy-driven conversion strategies for locally advanced rectal cancer].

Locally advanced rectal cancer (LARC) remains a major therapeutic challenge in multidisciplinary oncology. The increasing emphasis on early systemic intervention has positioned total neoadjuvant therapy (TNT) as a central treatment paradigm, with the potential to improve control of occult metastatic disease and enhance tumor response before definitive local therapy. Emerging data indicate that, in selected patients, neoadjuvant strategies dominated by systemic chemotherapy-sometimes with omission or de-escalation of radiotherapy-can maintain oncologic outcomes while reducing treatment-related toxicity, supporting a more individualized approach to local treatment.Marked heterogeneity in treatment response has become evident with the incorporation of immunotherapy. Patients with mismatch repair-deficient or microsatellite instability-high (dMMR/MSI-H) LARC may achieve profound and durable responses with immune checkpoint blockade alone.

In contrast, most LARC tumors are mismatch repair-proficient (pMMR/MSS) and demonstrate limited sensitivity to immunotherapy monotherapy. For this population, combination strategies incorporating immunotherapy with chemotherapy or other systemic agents have shown encouraging early efficacy in terms of tumor regression and surgical feasibility, although robust evidence for long-term survival benefit and optimal regimen selection is still lacking.Collectively, systemically driven conversion strategies enable earlier assessment of therapeutic sensitivity and provide a framework for risk-adapted, biology-informed treatment decision-making. Future efforts should focus on integrating imaging, molecular profiling, and early response assessment to refine patient selection, validate surrogate endpoints for long-term outcomes, and optimize treatment sequencing and safety in combined-modality approaches. 局部进展期直肠癌（LARC）患者是直肠癌综合治疗中的重点人群。近年来，随着系统治疗前移理念的提出，全程新辅助治疗（TNT）逐渐发展为LARC的重要治疗策略，为强化微转移灶控制、提高肿瘤降期率提供了新的选择。在以系统治疗模式为核心的转化治疗中，研究表明，严格筛选患者后，单纯或以化疗为主的新辅助策略可在保证肿瘤学疗效的同时减少放疗相关毒性，支持局部治疗个体化选择的可行性。对于错配修复缺陷（dMMR）/微卫星高度不稳定（MSI-H）型LARC，单用免疫检查点抑制剂即可诱导高比例的临床与病理缓解，相比之下，占绝大多数的错配修复完整（pMMR）/微卫星稳定（MSS）型LARC对免疫单药的治疗反应有限。针对此类患者，当前以免疫联合治疗为核心的系统治疗策略已初步显示出了较高的肿瘤退缩率和根治性切除率，但其长期生存获益及最优联合方案仍有待前瞻性验证。总体而言，以系统治疗为核心的转化治疗通过前移系统干预并系统性评估治疗反应，为基于分子学特征和早期疗效的风险分层与个体化决策提供了更为丰富的临床证据基础。未来，如何结合影像学、分子学特征及早期治疗反应精准筛选获益人群，明确短期疗效指标与长期生存之间的关联，并优化联合治疗的时序与安全性，将是推动以系统治疗为核心的转化治疗策略进一步发展的关键。.