基于递归分割分析模型的初发转移性鼻咽癌在放化疗后应用局部放疗的预后评估

化疗免疫治疗是初发转移性鼻咽癌（dmNPC）的一线治疗方案，加入局部放疗（LRRT）显著延长患者生存时间。然而，dmNPC表现出较大异质性，导致患者预后差异显著。我们开发并验证了一个针对接受一线化疗免疫治疗加LRRT患者的预后工具，旨在评估不同风险水平下局部治疗（LT）对远处转移的益处。研究了364例接受铂类化疗和抗程序性死亡蛋白1（PD-1）免疫治疗，随后进行LRRT的dmNPC患者。患者随机分为训练组和验证组（比例7:3）。主要终点为无进展生存期（PFS）。采用递归分割分析（RPA）建立PFS的预后模型。该模型根据转移病灶数、肝转移状态及治疗后EB病毒DNA水平将患者划分为五个预后组。生存分析显示，有三个风险组明显不同。高风险组的PFS明显低于中、低风险组（2年PFS率：训练组：13.7% vs 69.4% vs 94.4%，P < 0.001；验证组：7.8% vs 65.1% vs 87.3%，P < 0.001）。我们还分析了不同风险组中远处转移的局部治疗影响，发现只有中风险组患者从LT中获益（2年PFS率：77.5% vs 64.0%；风险比=0.535，95%可信区间0.297-0.966，P=0.035）。低风险组（P=0.218）和高风险组（P=0.793）未见明显生存获益。该基于RPA的预后模型结合转移灶数、肝转移状态及治疗后EB病毒DNA水平，可预测接受化疗免疫治疗加LRRT的dmNPC患者的PFS，提供个性化治疗指导，建议中风险组患者可能从远处转移的局部治疗中获益，而高、低风险组则可能无明显益处。

Chemoimmunotherapy is the first-line treatment of de novo metastatic nasopharyngeal carcinoma (dmNPC), with additional locoregional radiotherapy (LRRT) significantly prolonging patient survival. De novo metastatic nasopharyngeal carcinoma, however, demonstrates considerable heterogeneity, resulting in significant variability in patient outcomes. We developed and validated a prognostic tool for patients undergoing first-line chemoimmunotherapy plus LRRT and to evaluate the benefit of local therapy (LT) for distant metastases across different risk levels.We studied 364 dmNPC patients receiving initial platinum-based chemotherapy and anti-programmed cell death protein 1 immunotherapy followed by LRRT. Patients were randomly divided into training and validation cohorts (7 : 3 ratio). The primary endpoint was progression-free survival (PFS). A prognostic model for PFS was developed using recursive partitioning analysis (RPA).An RPA model categorized patients into five prognostic groups based on number of metastatic lesions, liver metastasis status, and post-treatment Epstein-Barr virus DNA levels. Survival analysis identified three distinct risk groups. High-risk patients had significantly poorer PFS compared with medium- and low-risk groups (2-year PFS rate: training cohort: 13.7% versus 69.4% versus 94.4%, P < 0.001; validation cohort: 7.8% versus 65.1% versus 87.3%, P < 0.001). We investigated the impact of LT for distant metastases across these risk groups and found that only patients in the medium-risk group derived benefit from LT (2-year PFS rate: 77.5% versus 64.0%; hazard ratio = 0.535, 95% confidence interval 0.297-0.966, P = 0.035). Conversely, no survival benefit from LT for distant metastases was observed in the low-risk (P = 0.218) and high-risk subgroups (P = 0.793).Our RPA-based prognostic model integrates number of metastatic lesions, liver metastasis status, and post-treatment Epstein-Barr virus DNA levels to predict PFS in dmNPC patients undergoing chemoimmunotherapy plus LRRT. This model offers personalized treatment guidance, suggesting that patients in the medium-risk group may benefit from LT for distant metastases, while those in high- and low-risk groups may not.