基因测序彻底改变了结直肠癌 (CRC) 的免疫治疗。最近的临床试验显示，具有微卫星不稳定性 (MSI) 高或 DNA 聚合酶 epsilon (POLE) 突变的 CRC 患者亚组对基于免疫疗法的全身治疗有积极反应。然而，不理想的缓解率是结直肠癌精准免疫治疗在现实世界实践中的主要限制。将光动力疗法（PDT）添加到全身免疫疗法中，通过调节肿瘤微环境显示出协同抗肿瘤作用，而适合从这种组合中受益的患者亚组仍然模棱两可。在这里，我们报道了一名患有 MSI-High 和 POLE 突变的同步结直肠癌患者，该患者在肿瘤定向 PDT 后不到 2 个周期（42 天）的基于免疫治疗的全身治疗中获得了加速反应，并且迄今为止仍保持无进展。该病例揭示了 PDT 对接受免疫疗法治疗的 CRC 患者的协同作用，其中 MSI 和 POLE 突变状态可作为生存获益的预测因子。版权所有 © 2024 Wang、Gao、Ma、Shi、Yin、Zhu 和 Chen。

Genetic sequencing has revolutionized immunotherapy in colorectal cancer (CRC). Recent clinical trials have revealed a positive response to immunotherapy-based systemic therapies in CRC patient subgroups with microsatellite instability (MSI)-High or DNA polymerase epsilon (POLE) mutation. However, the unsatisfactory response rates was the major limitation in real-world practice of the precision immunotherapy in CRC. Adding photodynamic therapy (PDT) to systemic immunotherapy has showed synergetic anti-tumor effect by modulating tumor microenvironment, while the eligible patient's subgroups which would benefit from this combination remained equivocal. Here we reported a synchronous colorectal cancer patient with MSI-High and POLE mutation who had accelerated response in less than 2 cycles (42 days) of immunotherapy-based systemic therapies after tumor-directed PDT and has remained progression-free by far. This case enlightened the synergetic effect of PDT in immunotherapy-treated CRC patients, with the MSI and POLE-mutation status as predictors of survival benefits.Copyright © 2024 Wang, Gao, Ma, Shi, Yin, Zhu and Chen.