Division of Radiation Oncology, University Hospital Maggiore della Carità, Novara, Italy.
Department of Translational Medicine, University of "Piemonte Orientale", Via Solaroli, 17, 28100, Novara, Italy.
Radiat Oncol. 2021 Mar 21;16(1):57. doi: 10.1186/s13014-021-01787-5.
To analyze the pattern of failure in relation to pre-treatment [F] FDG-PET/CT uptake in head and neck squamous cell carcinoma (HNSCC) patients treated with definitive radio-chemotherapy (RT-CHT).
From 2012 to 2016, 87 HNSCC patients treated with definitive RT-CHT, with intensity modulated radiation therapy with simultaneous integrated boost, underwent pre-treatment [F] FDG-PET/CT (PET), and MRI/CT for radiotherapy (RT) planning purposes. Patients with local recurrence, received [F] FDG-PET/CT, (PET) at the time of the discovery of recurrence. In these patients, the metabolic target volume (MTV), MTV and MTV were segmented on PET images by means of an adaptive thresholding algorithm. The overlapping volume between MTV and MTV (MTV) was generated and the dose coverage of MTV and MTV was checked on the planning CT using the D99 and D95 dose metrics. The recurrent volume was defined as: ''In-Field (IF)'', "Marginal recurrence" or ''Out-of-Field (OF)'' if D95 was respectively equal or higher than 95%, D95 was between 95 and 20% or the D95 was less than 20% of prescribed dose.
We found 10/87 patients (11.5%) who had recurrence at primary site. Mean MTV was 12.2 cc (4.6-28.9 cc), while the mean MTV was 4.3 cc (1.1-12.7 cc). Two recurrences resulted 100% inside MTV, 4 recurrences were mostly inside (61-91%) and 4 recurrences were marginal to MTV (1-33%). At dosimetric analysis, five recurrences (50%) were IF, 4 (40%) marginal and one (10%) OF. The mean D99 of the overlapping volumes MTV was 68.1 Gy (66.5-69.2 Gy), considering a prescription dose of 70 Gy to the planning target volume (PTV).
Our study shows that the recurrence may originate from the volume with the highest FDG-signal. Tumor relapse in the high-dose volume support the hypothesis that an intensification of the dose on these volumes could be further assessed to prevent local relapse.
分析头颈部鳞状细胞癌（HNSCC）患者在接受根治性放化疗（RT-CHT）后，与治疗前 [F] FDG-PET/CT 摄取相关的失败模式。
2012 年至 2016 年，87 例接受根治性 RT-CHT 的 HNSCC 患者在接受强化调强放疗的同时接受了治疗前 [F] FDG-PET/CT（PET）检查，同时还进行了 MRI/CT 放疗计划。局部复发的患者在发现复发时接受了 [F] FDG-PET/CT（PET）检查。在这些患者中，代谢靶区（MTV）、MTV 和 MTV 通过自适应阈值算法在 PET 图像上进行分割。生成 MTV 和 MTV 之间的重叠体积（MTV），并在计划 CT 上使用 D99 和 D95 剂量指标检查 MTV 和 MTV 的剂量覆盖情况。复发体积定义为：如果 D95 分别等于或高于 95%、D95 处于 95%和 20%之间或 D95 低于规定剂量的 20%，则为“靶区内（IF）”、“边缘复发”或“靶区外（OF）”。
我们发现 10/87 例（11.5%）患者在原发部位复发。平均 MTV 为 12.2cc（4.6-28.9cc），而平均 MTV 为 4.3cc（1.1-12.7cc）。2 次复发完全在 MTV 内，4 次复发主要在 MTV 内（61-91%），4 次复发接近 MTV（1-33%）。在剂量分析中，5 次复发（50%）为 IF，4 次（40%）为边缘，1 次（10%）为 OF。考虑到计划靶区（PTV）的 70Gy 处方剂量，重叠 MTV 体积的平均 D99 为 68.1Gy（66.5-69.2Gy）。
我们的研究表明，复发可能源自 FDG 信号最强的体积。高剂量体积中的肿瘤复发支持了这样一种假设，即在这些体积上强化剂量可以进一步评估，以防止局部复发。
