Botticella A, Defraene G, Nackaerts K, Deroose C, Coolen J, Nafteux P, Vanstraelen B, Joosten S, Michiels L A W, Peeters S, De Ruysscher D
Department of Oncology, Experimental Radiation Oncology, KU Leuven - University of Leuven, 3000, Leuven, Belgium.
Department of Respiratory Medicine, KU Leuven - University of Leuven, University Hospitals Leuven, 3000, Leuven, Belgium.
Strahlenther Onkol. 2017 Apr;193(4):285-294. doi: 10.1007/s00066-017-1108-y. Epub 2017 Feb 14.
After lung-sparing radiotherapy for malignant pleural mesothelioma (MPM), local failure at sites of previous gross disease represents the dominant form of failure. Our aim is to investigate if selective irradiation of the gross pleural disease only can allow dose escalation.
In all, 12 consecutive stage I-IV MPM patients (6 left-sided and 6 right-sided) were retrospectively identified and included. A magnetic resonance imaging-based pleural gross tumor volume (GTV) was contoured. Two sets of planning target volumes (PTV) were generated for each patient: (1) a "selective" PTV (S-PTV), originating from a 5-mm isotropic expansion from the GTV and (2) an "elective" PTV (E-PTV), originating from a 5-mm isotropic expansion from the whole ipsilateral pleural space. Two sets of volumetric modulated arc therapy (VMAT) treatment plans were generated: a "selective" pleural irradiation plan (SPI plan) and an "elective" pleural irradiation plan (EPI plan, planned with a simultaneous integrated boost technique [SIB]).
In the SPI plans, the average median dose to the S‑PTV was 53.6 Gy (range 41-63.6 Gy). In 4 of 12 patients, it was possible to escalate the dose to the S‑PTV to >58 Gy. In the EPI plans, the average median doses to the E‑PTV and to the S‑PTV were 48.6 Gy (range 38.5-58.7) and 49 Gy (range 38.6-59.5 Gy), respectively. No significant dose escalation was achievable.
The omission of the elective irradiation of the whole ipsilateral pleural space allowed dose escalation from 49 Gy to more than 58 Gy in 4 of 12 chemonaive MPM patients. This strategy may form the basis for nonsurgical radical combined modality treatment of MPM.
对于恶性胸膜间皮瘤（MPM），在进行保留肺的放射治疗后，先前大体病灶部位的局部失败是主要的失败形式。我们的目的是研究仅对大体胸膜疾病进行选择性照射是否能实现剂量递增。
总共回顾性纳入了12例I-IV期MPM患者（左侧6例，右侧6例）。基于磁共振成像勾勒出胸膜大体肿瘤体积（GTV）。为每位患者生成两组计划靶体积（PTV）：（1）“选择性”PTV（S-PTV），由GTV各向同性扩展5毫米生成；（2）“选择性”PTV（E-PTV），由整个同侧胸膜腔各向同性扩展5毫米生成。生成两组容积调强弧形治疗（VMAT）治疗计划：“选择性”胸膜照射计划（SPI计划）和“选择性”胸膜照射计划（EPI计划，采用同步整合加量技术[SIB]规划）。
在SPI计划中，S-PTV的平均中位剂量为53.6 Gy（范围41-63.6 Gy）。12例患者中有4例能够将S-PTV的剂量递增至>58 Gy。在EPI计划中，E-PTV和S-PTV的平均中位剂量分别为48.6 Gy（范围38.5-58.7）和49 Gy（范围38.6-59.5 Gy）。无法实现显著的剂量递增。
在12例未接受过化疗的MPM患者中，有4例通过省略对整个同侧胸膜腔的选择性照射，可将剂量从49 Gy递增至超过58 Gy。该策略可能构成MPM非手术根治性综合治疗的基础。
