Department of Oncology, The Third Xiangya Hospital of Central South University, Central South University, Changsha, China.
Department of Oncology, Xiangxi Autonomous Prefecture People's Hospital, Ji Shou University, Jishou, China.
BMC Cancer. 2024 Sep 27;24(1):1198. doi: 10.1186/s12885-024-12979-z.
A dosimetric evaluation is still lacking in terms of clinical target volume (CTV) omission in stage III patients treated with 4D-CT Intensity-Modulated Radiation Therapy (IMRT).
49 stage III NSCLC patients received 4D-CT IMRT were reviewed. Target volumes and organs at risk (OARs) were re-delineated. Four IMRT plans were conducted retrospectively to deliver different prescribed dose (74 Gy-60 Gy), and with or without CTV implementation. Dose and volume histogram (DVH) parameters were collected and compared.
In the PTV-g 60 Gy plan (PTV-g refers to the PTV generated from the internal gross tumor volume), only 5 of 49 patients had the isodose ≥ 50 Gy line covering at least 95% of the PTV-c (PTV-c refers to the PTV generated from the internal CTV) volume. When the prescribed dose was elevated to 74 Gy to the PTV-g, 33 of 49 patients could have the isodose ≥ 50 Gy line covering at least 95% of the PTV-c volume. In terms of OARs protection, the SIB-IMRT plan showed the lowest value of V5, V20, and mean dose of lung, had the lowest V55 of esophagus, and the lowest estimated radiation doses to immune cells (EDIC). The V20, V30, and mean dose of heart was lower in the simultaneous integrated boost (SIB) IMRT (SIB-IMRT) plan than that of the PTV-c 60 Gy plan.
CTV omission was not suitable for stage III patients when the prescribed dose to PTV-g was 60 Gy in the era of 4D-CT IMRT. CTV omission plus high dose to PTV-g (74 Gy for example) warranted further exploration. The SIB-IMRT plan had the best protection to normal tissue including lymphocytes, and might be the optimal choice.
在采用四维 CT 调强放疗（IMRT）治疗 III 期患者时，临床靶区（CTV）遗漏的剂量学评估仍存在不足。
回顾性分析 49 例接受 4D-CT-IMRT 治疗的 III 期非小细胞肺癌患者。重新勾画靶区和危及器官（OARs）。回顾性地进行了 4 个 IMRT 计划，以提供不同的规定剂量（74Gy-60Gy），并分别实施和不实施 CTV。收集并比较剂量和体积直方图（DVH）参数。
在 PTV-g 60Gy 计划（PTV-g 是指从内部大体肿瘤体积生成的 PTV）中，只有 5 例患者的等剂量线（isodose line）≥50Gy 线覆盖了 PTV-c（PTV-c 是指从内部 CTV 生成的 PTV）体积的至少 95%。当将规定剂量提高到 PTV-g 的 74Gy 时，49 例患者中有 33 例患者的等剂量线≥50Gy 线覆盖了 PTV-c 体积的至少 95%。在保护 OARs 方面，SIB-IMRT 计划的 V5、V20 和肺的平均剂量最低，食管的 V55 最低，免疫细胞（EDIC）的估计辐射剂量最低。与 PTV-c 60Gy 计划相比，同步整合推量（SIB）IMRT（SIB-IMRT）计划的 V20、V30 和心脏的平均剂量较低。
在 4D-CT-IMRT 时代，当 PTV-g 的规定剂量为 60Gy 时，III 期患者不适合进行 CTV 遗漏。CTV 遗漏加高剂量至 PTV-g（例如 74Gy）需要进一步探索。SIB-IMRT 计划对包括淋巴细胞在内的正常组织具有最佳保护作用，可能是最佳选择。
