Lucia François, Bourbonne Vincent, Gujral Dorothy, Dissaux Gurvan, Miranda Omar, Mauguen Maelle, Pradier Olivier, Abgral Ronan, Schick Ulrike
Radiation Oncology Department, University Hospital, Brest, France.
Clinical Oncology Department, Imperial College Healthcare NHS Trust, Charing Cross Hospital, Hammersmith, London, UK.
Clin Transl Radiat Oncol. 2020 May 11;23:50-59. doi: 10.1016/j.ctro.2020.05.004. eCollection 2020 Jul.
Areas of high uptake on pre-treatment F-fluorodeoxyglucose (F-FDG) positron emission tomography/computed tomography (PET/CT), denoted as "hotspots", have been identified as preferential sites of local relapse in locally advanced cervical cancer (LACC). The purpose of this study was to analyze the dosimetric coverage of these hotspots with high dose-rate brachytherapy (BT).
For each patient, a rigid registration of the CT from the pre-treatment PET/CT with the radiotherapy planning CT was performed using 3D Slicer, followed by a manual volume correction by translation and deformation if necessary. The fuzzy locally adaptive Bayesian (FLAB) algorithm was applied to PET images to simultaneously define an overall tumour volume and the high-uptake sub-volume V1. The inclusion of V1 in the high-risk clinical target volume (CTV HR) and its dosimetric coverage were evaluated using 3D Slicer. The average of the 3-4 BT sessions was reported.
Forty-two patients with recurrence after chemoradiotherapy (CRT) for LACC were matched to 42 patients without recurrence. Mean ± standard deviation follow-up was 26 ± 11 months. In the recurrence group, V1 was not included in the CTV HR and not covered by the 85 Gy isodose in 17/42 patients (41%) (1/20 with pelvic recurrence and 16/22 with distant recurrence) and not by the 80 Gy isodose in 7/42 patients (17%) (all with distant recurrence). In the non-recurrence group, V1 was not included in CTV HR and not covered by the 85 Gy isodose in 3 patients only (7%). The hotspots coverage by the 85 Gy isodose was significantly better in patients who did not recur, but only when compared to patients with distant relapse (p < 0.0001).
Suboptimal dosimetric coverage of high FDG uptakes on pretherapeutic PET could be associated with an increased risk of recurrence.
在局部晚期宫颈癌（LACC）中，治疗前氟脱氧葡萄糖（F-FDG）正电子发射断层扫描/计算机断层扫描（PET/CT）上高摄取区域（称为“热点”）已被确定为局部复发的优先部位。本研究的目的是分析高剂量率近距离放疗（BT）对这些热点的剂量覆盖情况。
对于每位患者，使用3D Slicer对治疗前PET/CT的CT与放射治疗计划CT进行刚性配准，必要时通过平移和变形进行手动体积校正。将模糊局部自适应贝叶斯（FLAB）算法应用于PET图像，以同时定义总体肿瘤体积和高摄取子体积V1。使用3D Slicer评估V1纳入高危临床靶体积（CTV HR）及其剂量覆盖情况。报告3 - 4次BT疗程的平均值。
42例LACC放化疗（CRT）后复发的患者与42例未复发的患者匹配。平均随访时间±标准差为26±11个月。在复发组中，17/42例患者（41%）（盆腔复发1/20例，远处复发16/22例）的V1未纳入CTV HR且未被85 Gy等剂量线覆盖，7/42例患者（17%）（均为远处复发）的V1未被80 Gy等剂量线覆盖。在未复发组中，仅3例患者（7%）的V1未纳入CTV HR且未被85 Gy等剂量线覆盖。未复发患者中85 Gy等剂量线对热点的覆盖明显更好，但仅与远处复发患者相比时（p < 0.0001）。
治疗前PET上高FDG摄取区域的剂量覆盖欠佳可能与复发风险增加有关。
