Purpose

This retrospective study aimed to identify the factors associated with cavity formation after SBRT in peripheral early-stage lung cancer patients. We analyzed the occurrence of cavity changes after SBRT.

Materials and Methods

We examined 99 cases with T1-T2aN0 peripheral non-small cell lung cancer treated with SBRT from 2004 to 2021. Patients underwent respiratory function tests, including diffusing capacity for carbon monoxide (DLco), before treatment. The median observation period was 35 months (IQR 18–47.5 months). Treatment involved fixed multi-portal irradiation in 67% of cases and VMAT in 33%. The total radiation doses ranged from 42 to 55 Gy, delivered over 4 to 5 fractions.

Results

Cavity formation occurred in 14 cases (14.1%), appearing a median of 8 months after SBRT. The cavity disappeared in a median of 4 months after formation. High DLco and total radiation dose were identified as factors significantly associated with cavity formation. There have been no confirmed recurrences to date, but one patient developed a lung abscess.

Conclusion

Although cavity formation after SBRT for peripheral early-stage lung cancer is infrequent, it can occur. This study showed high DLco and total radiation dose to be factors significantly associated with cavity formation. These findings can be applied to optimizing radiation therapy (RT) and improving patient outcomes. Further research is needed to determine the optimal radiation dose for patients with near-normal DLco for whom surgery is an option. This study provides valuable insights into image changes after RT.

中文翻译：

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周围型早期肺癌立体定向放射治疗后空洞形成的相关因素

目的

这项回顾性研究旨在确定周围型早期肺癌患者 SBRT 后空洞形成的相关因素。我们分析了 SBRT 后空腔变化的发生情况。

材料和方法

我们检查了 2004 年至 2021 年接受 SBRT 治疗的 99 例 T1-T2aN0 周围型非小细胞肺癌患者。患者在治疗前接受了呼吸功能测试，包括一氧化碳弥散能力 (DLco)。中位观察期为 35 个月（IQR 18-47.5 个月）。67% 的病例采用固定多孔照射，33% 采用 VMAT 治疗。总辐射剂量范围为 42 至 55 Gy，分 4 至 5 次进行。

结果

14 例（14.1%）发生空洞形成，中位时间为 SBRT 后 8 个月。空洞形成后平均 4 个月消失。高 DLco 和总辐射剂量被确定为与空腔形成显着相关的因素。迄今为止，尚未确认复发情况，但一名患者出现了肺脓肿。

结论

尽管周围型早期肺癌 SBRT 后形成空洞的情况很少见，但还是有可能发生。这项研究表明高 DLco 和总辐射剂量是与空洞形成显着相关的因素。这些发现可用于优化放射治疗 (RT) 和改善患者治疗效果。需要进一步研究来确定 DLco 接近正常且可以选择手术的患者的最佳放射剂量。这项研究为 RT 后的图像变化提供了有价值的见解。