Aside from surgical resection, locally advanced rectal cancer is regularly treated with neoadjuvant chemoradiotherapy. Since the concept of cancer treatment has shifted from only focusing on tumor cells as drivers of disease progression towards a broader understanding including the dynamic tumor microenvironment (TME), the impact of radiotherapy on the TME and specifically the tumor immune microenvironment (TIME) is increasingly recognized. Both promoting as well as suppressing effects on anti-tumor immunity have been reported in response to rectal cancer (chemo-)radiotherapy and various targets for combination therapies are under investigation. A literature review was conducted searching the PubMed database for evidence regarding the pleiotropic effects of (chemo-)radiotherapy on the rectal cancer TIME, including alterations in cytokine levels, immune cell populations and activity as well as changes in immune checkpoint proteins. Radiotherapy can induce immune-stimulating and -suppressive alterations, potentially mediating radioresistance. The response is influenced by treatment modalities, including the dosage administered and the highly individual intrinsic pre-treatment immune status. Directly addressing the main immune cells of the TME, this review aims to highlight therapeutical implications since efficient rectal cancer treatment relies on personalized strategies combining conventional therapies with immune-modulating approaches, such as immune checkpoint inhibitors.
除手术切除外，局部进展期直肠癌常规采用新辅助放化疗进行治疗。随着癌症治疗理念从仅关注肿瘤细胞作为疾病进展驱动因素，转向更广泛地理解包括动态肿瘤微环境（TME）在内的整体机制，放疗对TME尤其是肿瘤免疫微环境（TIME）的影响日益受到重视。现有研究报道了直肠癌（放）化疗对抗肿瘤免疫既存在促进作用也存在抑制效应，目前多种联合治疗靶点正在探索中。本文通过检索PubMed数据库，系统综述了（放）化疗对直肠癌TIME的多效性影响，包括细胞因子水平变化、免疫细胞群数量与活性改变以及免疫检查点蛋白表达变化。放疗可诱导免疫刺激性和抑制性改变，这些变化可能介导放疗抵抗。治疗效果受治疗模式影响，包括给药剂量和高度个体化的治疗前固有免疫状态。本综述聚焦TME中的主要免疫细胞，旨在阐明治疗意义，因为有效的直肠癌治疗依赖于将传统疗法与免疫调节策略（如免疫检查点抑制剂）相结合的个体化方案。
肿瘤(癌症)患者之家