Aims

To report late toxicity and long-term outcomes of intensity-modulated radiotherapy (IMRT)-based stereotactic ablative body radiotherapy (SABR) in patients with ultra-central lung tumours.

Materials and Methods

This is a single-institution retrospective analysis of patients treated with SABR for ultra-central tumours between May 2008 and April 2016. Ultra-central location was defined as tumour (GTV) abutting or involving trachea, main or lobar bronchi. Respiratory motion management and static-field dynamic-IMRT were used, with dose prescribed homogeneously (maximum <120%). Descriptive analysis, Kaplan–Meier method, log-rank test and Cox regression were used to assess outcomes.

Results

Sixty-five per cent of patients had inoperable primary non-small cell lung cancer and 35% had lung oligometastases. The median age was 72 (range 34–85) years. The median gross tumour volume and planning target volume (PTV) were 19.6 (range 1.7–203.3) cm³ and 57.4 (range 7.7–426.6) cm³, respectively. The most commonly used dose fractionation was 60 Gy in eight fractions (n = 51, 87.8%). Median BED₁₀ for D98%PTV and D2%PTV were 102.6 Gy and 115.06 Gy, respectively. With a median follow-up of 26.5 (range 3.2–100.5) months, fatal haemoptysis occurred in five patients (8.7%), of which two were directly attributable to SABR. A statistically significant difference was identified between median BED₃ for 4 cm³ of airway, for patients who developed haemoptysis versus those who did not (147.4 versus 47.2 Gy, P = 0.005). At the last known follow-up, 50 patients (87.7%) were without local recurrence. Freedom from local progression at 2 and 4 years was 92 and 79.8%, respectively. The median overall survival was 34.3 (95% confidence interval 6.1–61.6) months. Overall survival at 2 and 4 years was 55.1 and 41.2%, respectively.

Conclusion

In patients with high-risk ultra-central lung tumours, IMRT-based SABR with homogenous dose prescription achieves high local control, similar to that reported for peripheral tumours. Although fatal haemoptysis occurred in 8.7% of patients, a direct causality with SABR was evident in only 3%. Larger studies are warranted to ascertain factors associated with outcomes, especially toxicity, and identify patients who would probably benefit from this treatment.

中文翻译：

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基于调强放疗的立体定向消融体放射治疗超中央肺肿瘤患者的晚期毒性和长期局部控制

宗旨

报告基于调强放疗 (IMRT) 的立体定向消融体放疗 (SABR) 在超中央肺肿瘤患者中的晚期毒性和长期结果。

材料和方法

这是对 2008 年 5 月至 2016 年 4 月期间接受 SABR 治疗的超中央肿瘤患者的单机构回顾性分析。超中央位置定义为肿瘤 (GTV) 邻接或累及气管、主支气管或大叶支气管。使用了呼吸运动管理和静态场动态 IMRT，剂量均匀（最大 <120%）。描述性分析、Kaplan-Meier 方法、对数秩检验和 Cox 回归用于评估结果。

结果

65% 的患者患有无法手术的原发性非小细胞肺癌，35% 患有肺寡转移。中位年龄为 72（范围 34-85）岁。中位肿瘤总体积和计划靶体积 (PTV) 分别为 19.6（范围 1.7-203.3）cm ³和 57.4（范围 7.7-426.6）cm ³。最常用的剂量分割是 60 Gy，分为 8 个分割 ( n = 51, 87.8%)。D98%PTV 和 D2%PTV 的中位 BED ₁₀分别为 102.6 Gy 和 115.06 Gy。中位随访时间为 26.5（3.2-100.5）个月，5 名患者（8.7%）发生致命咯血，其中 2 名直接归因于 SABR。中位 BED ₃之间存在统计学显着差异，持续 4 cm³气道，发生咯血的患者与未发生咯血的患者相比（147.4 与 47.2 Gy，P = 0.005）。在最后一次已知的随访中，50 名患者 (87.7%) 没有局部复发。2 年和 4 年时局部进展的自由度分别为 92% 和 79.8%。中位总生存期为 34.3（95% 置信区间 6.1-61.6）个月。2 年和 4 年的总生存率分别为 55.1% 和 41.2%。

结论

在高危超中央肺肿瘤患者中，基于 IMRT 的 SABR 与均匀剂量处方实现了高度的局部控制，类似于外周肿瘤的报道。尽管 8.7% 的患者发生了致命的咯血，但与 SABR 有直接因果关系的患者仅占 3%。需要更大规模的研究来确定与结果相关的因素，尤其是毒性，并确定可能从这种治疗中受益的患者。