Purpose

In patients with node-positive endometrial cancer, adjuvant radiation therapy with chemotherapy decreases local-regional recurrence compared with chemotherapy alone. However, the optimal radiation field borders and extent of nodal coverage have not been well studied. In a multi-institutional cohort, survival outcomes and sites of failure were analyzed for patients with International Federation of Gynaecology and Obstetrics (FIGO) stage IIIC endometrioid endometrial cancer treated with pelvic radiation therapy (PRT) versus extended-field radiation therapy (EFRT), which encompassed high para-aortic lymph nodes.

Methods and Materials

In a multi-institutional retrospective study, 143 patients with FIGO stage IIIC1 or IIIC2 endometrioid endometrial cancer treated with adjuvant radiation therapy from 2000 to 2016 were identified. Patient subgroups were classified by substage and radiation field extent: stage IIIC1 received EFRT, stage IIIC1 received PRT, and stage IIIC2 received EFRT. Recurrence-free survival (RFS), overall survival (OS), and out-of-field recurrence were calculated by the Kaplan-Meier method. Multivariate analysis was performed using the Cox proportional hazards model. Sites of failure were categorized as within or outside the radiation field.

Results

The median follow-up was 59 months; 87% of patients received chemotherapy. The 5-year RFS and OS rates were 73% and 87%, respectively. By subgroup, 5-year RFS rates were 79% for stage IIIC1 EFRT, 73% for stage IIIC1 PRT, and 69% for stage IIIC2 EFRT (P = .4). On multivariate analysis, the recurrence risk was highest for stage IIIC2 EFRT, although this result was not statistically significant (adjusted hazard ratio, 2.0; P = .4). In-field vaginal and nodal recurrences were observed in 2 patients (1%) and 4 patients (3%), respectively. Of 78 patients with stage IIIC1 cancer treated with PRT, 5 (6%) had isolated para-aortic nodal relapse outside the radiation field; 3 were long-term survivors (more than 6 years after salvage therapy). For patients with para-aortic recurrence, 86% had lymphovascular invasion, 71% had myometrial invasion of ≥50%, and 57% had grade 3 disease.

Conclusions

Adjuvant chemoradiation therapy resulted in excellent survival outcomes for patients with FIGO stage IIIC endometrioid endometrial cancer. For patients with positive pelvic nodes, isolated para-aortic relapse outside the PRT field was uncommon and amenable to salvage therapy.

中文翻译：

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淋巴结阳性子宫内膜样子宫内膜癌的辅助放射野范围和失败部位

目的

在淋巴结阳性子宫内膜癌患者中，与单独化疗相比，辅助放疗联合化疗可减少局部复发。然而，最佳辐射场边界和节点覆盖范围尚未得到很好的研究。在一个多机构队列中，对接受盆腔放射治疗 (PRT) 与大范围放射治疗 (EFRT) 治疗的国际妇产科联合会 (FIGO) IIIC 期子宫内膜样子宫内膜癌患者的生存结果和失败部位进行了分析，其中包括高位主动脉旁淋巴结。

方法和材料

在一项多机构回顾性研究中，确定了 2000 年至 2016 年接受辅助放射治疗的 143 名FIGO IIIC1 或IIIC2 期子宫内膜样子宫内膜癌患者。患者亚组按亚阶段和辐射野范围进行分类：IIIC1 期接受 EFRT，IIIC1 期接受 PRT，IIIC2 期接受 EFRT。采用 Kaplan-Meier 方法计算无复发生存期 (RFS)、总生存期 (OS) 和场外复发率。使用 Cox 比例风险模型进行多变量分析。故障部位分为辐射场内或辐射场外。

结果

中位随访时间为 59 个月；87%的患者接受了化疗。5 年 RFS 和 OS 率分别为 73% 和 87%。按亚组划分，IIIC1 期 EFRT 的 5 年 RFS 率为 79%，IIIC1 期 PRT 为 73%，IIIC2 期 EFRT 为 69%（P  = .4）。在多变量分析中，IIIC2 期 EFRT 的复发风险最高，尽管这一结果没有统计学意义（调整后的风险比，2.0；P = .4)。分别在 2 名患者 (1%) 和 4 名患者 (3%) 中观察到现场阴道和淋巴结复发。在接受 PRT 治疗的 78 名 IIIC1 期癌症患者中，5 名 (6%) 在放射野外出现孤立的主动脉旁淋巴结复发；3 人是长期幸存者（抢救治疗后超过 6 年）。对于主动脉旁复发的患者，86% 有淋巴血管浸润，71% 有肌层浸润≥50%，57% 有 3 级疾病。

结论

辅助放化疗为FIGO IIIC期子宫内膜样子宫内膜癌患者带来了极好的生存结果。对于盆腔淋巴结阳性的患者，PRT 野外孤立的主动脉旁复发并不常见，并且可以进行抢救治疗。