Weiskittel Taylor M, Harmsen William S, Mahajan Anita, Petersen Ivy A, Haddock Michael G, Allen-Rhoades Wendy, Robinson Steven I, Laack Nadia N, Ahmed Safia K
Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota.
Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester, Minnesota.
Adv Radiat Oncol. 2025 Jun 9;10(8):101820. doi: 10.1016/j.adro.2025.101820. eCollection 2025 Aug.
Dose escalation for definitive radiation therapy (DE-RT) in larger Ewing sarcomas (ESs) is associated with a lower risk of local recurrence. We report treatment and toxicity outcomes in ES tumors treated with DE-RT, including hypofractionated approaches and size stratification of analysis.
A retrospective review of ES patients treated with DE-RT to doses ≥55.8 Gy was performed. Local failure (LF) with death as a competing risk was assessed. Maximally selected rank statistics were used to determine the optimal stratification of patients by survival using tumor size measurements.
In total, 47 patients were analyzed. Twenty-eight patients (59.6%) received DE-RT, of which 6 received hypofractionation. For DE-RT, median equivalent dose in 2 Gy fraction for α/β = 10 was 60 Gy (range, 56.2-62) with conventional fractionation and 62.2 Gy (range, 56.5-67.1) with hypofractionation. Empirically derived size cutoffs identified a subgroup of ultralarge tumors at higher risk of LF defined as >11.8 cm in the longest direction, 569.2 cm prechemotherapy volume, or 288.9 cm postchemotherapy volume. Five-year cumulative incidence of LF was lower in patients treated with DE-RT at 11.7% (95% CI, 3.16%-43.6%) versus 35.6% for non-DE-RT (95% CI, 17.4%-72.61%; = .098). Multivariate analysis showed trends toward DE-RT benefiting tumors of all sizes and stages.
DE-RT was associated with a trend toward better LF in all tumors without toxicity or plan quality changes. Ultralarge tumors demonstrated poor LF rates and necessitate further study.
在较大的尤因肉瘤（ES）中，确定性放射治疗（DE-RT）的剂量递增与局部复发风险较低相关。我们报告了接受DE-RT治疗的ES肿瘤的治疗和毒性结果，包括超分割方法和分析的大小分层。
对接受DE-RT且剂量≥55.8 Gy的ES患者进行回顾性研究。评估以死亡作为竞争风险的局部失败（LF）情况。使用最大选择秩统计量，通过肿瘤大小测量来确定患者生存的最佳分层。
总共分析了47例患者。28例患者（59.6%）接受了DE-RT，其中6例接受了超分割。对于DE-RT，α/β = 10时，2 Gy分割的等效中位剂量，常规分割为60 Gy（范围56.2 - 62），超分割为62.2 Gy（范围56.5 - 67.1）。根据经验得出的大小临界值确定了一组超大肿瘤，其LF风险较高，定义为最长径>11.8 cm、化疗前体积>569.2 cm或化疗后体积>288.9 cm。接受DE-RT治疗患者的5年LF累积发生率较低，为11.7%（95% CI，3.16% - 43.6%），而非DE-RT患者为35.6%（95% CI，17.4% - 72.61%；P = 0.098）。多因素分析显示DE-RT对所有大小和分期的肿瘤均有获益趋势。
DE-RT与所有肿瘤中LF改善的趋势相关，且无毒性或计划质量改变。超大肿瘤显示出较差的LF率，需要进一步研究。
