Department of Radio-Oncology, Medical School Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
Joint Practice Radiooncology Hannover, Rundestr. 10, 30161, Hannover, Germany.
Radiat Oncol. 2017 Nov 2;12(1):165. doi: 10.1186/s13014-017-0898-5.
Radiation pneumonitis (RP) is the most common subacute side effect after concurrent chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer. Several clinical and dose-volume (DV) parameters are associated with a distinct risk of symptomatic RP. The aim of this study was to assess the spatial dose distribution of the RP volume from first occurence to maximum volume expansion of RP.
Between 2007 and 2015, 732 patients with lung cancer were treated in an institution. Thirty-three patients met the following inclusion criteria: an RP grade II after CRT and a radiation dose ≥60 Gy and no prior medical history of cardiopulmonary comorbidities. The images of the first chest computed tomography (CT) confirming the diagnosis of RP and the CT images showing the maximum expansion of RP were merged with the treatment plan. The RP volume was delineated within the treatment plan, and a DV analysis was performed to evaluate the lung dose volume areas in which the RP manifested over time and whether dose volume changes within the RP volume occurred.
A change from clinical diagnosis to maximum expansion of RP was observed as the RP at clinical appearance mainly manifested in the lower dose areas of the lung, whereas the RP volume at maximum expansion manifested in the higher dose areas, resulting in a significant shift of the assessed relative mean dose volume proportions within the RP volume. The mean relative dose volume proportion 0- ≤ 20 Gy decreased from 30.2% (range, 0-100) to 21.9% (range, 0-100; p = 0.04) at the expense of the dose volume > 40 Gy which increased from 39.2% (range, 0-100) to 49.8% (range, 0-100; p = 0.02), whereas the dose relative volume proportion > 20- ≤ 40 Gy showed no relevant change and slightly decreased from 30.6% (range, 0-85.7) to 28.3%, (range, 0-85.7; p = 0.34).
We observed a considerable increase in the relative dose proportions within the RP volume from diagnosis to maximum volume extent from low dose zones below 20 Gy to zones above 40 Gy. Although the clinical impact on RP remains unknown, a reduction of healthy healthy lung tissue receiving >40 Gy (V40) might be an additional parameter for irradiation planning in lung cancer patients.
放射性肺炎（RP）是局部晚期非小细胞肺癌同步放化疗后最常见的亚急性副作用。一些临床和剂量-体积（DV）参数与症状性 RP 的发生风险明显相关。本研究旨在评估从首次发生到 RP 最大体积扩展过程中 RP 体积的空间剂量分布。
2007 年至 2015 年间，732 例肺癌患者在我院接受治疗。33 例患者符合以下纳入标准：放化疗后出现 II 级 RP，且放射剂量≥60Gy，且无心肺合并症的既往病史。首次胸部 CT（CT）诊断为 RP 及 CT 显示 RP 最大扩展的图像与治疗计划融合。在治疗计划中勾画 RP 体积，并进行 DV 分析，以评估随时间推移 RP 出现的肺剂量体积区域，以及 RP 体积内的剂量体积变化。
从临床诊断到 RP 最大扩展的变化表明，RP 在临床出现时主要表现为肺的低剂量区域，而 RP 体积在最大扩展时表现为高剂量区域，导致 RP 体积内评估的相对平均剂量体积比例发生显著移位。RP 体积内 0-≤20Gy 的平均相对剂量体积比例从 30.2%（范围：0-100）降至 21.9%（范围：0-100；p=0.04），而>40Gy 的剂量体积比例从 39.2%（范围：0-100）增至 49.8%（范围：0-100；p=0.02），而>20-≤40Gy 的剂量相对体积比例没有相关变化，从 30.6%（范围：0-85.7）降至 28.3%（范围：0-85.7；p=0.34）。
我们观察到从诊断到最大体积范围，RP 体积内的相对剂量比例从 20Gy 以下的低剂量区显著增加到 40Gy 以上的剂量区。虽然 RP 的临床影响尚不清楚，但减少接受>40Gy（V40）的健康肺组织可能是肺癌患者放疗计划的另一个参数。
