Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands.
Radiother Oncol. 2018 May;127(2):259-266. doi: 10.1016/j.radonc.2018.03.020. Epub 2018 Apr 27.
FDG-PET scans have shown spatial consistency in NSCLC patients before and following chemoradiotherapy, implying radioresistance. We hypothesized that patients, who received FDG-PET redistributed dose painting, would demonstrate reduced spatial consistency when compared to registered patients or to escalated dose treatment.
Stage II-IIIB, inoperable NSCLC patients were randomized in a phase II trial (NCT01024829) to (chemo)radiotherapy of either homogeneous boosting to the primary tumor, or redistributed inhomogeneous boosting to the GTV subvolume (FDG-SUV > 50% SUV). Patients who could not be boosted (≥72 Gy) received 66 Gy in 24 fractions. Spatial consistency of pre-treatment and post-treatment (3 months) FDG-PET scans was measured by various overlap fraction thresholds.
66/82 patients analyzed received randomized treatment in the trial. Thresholds of 50% SUV pre-treatment and 70% SUV post-treatment yielded a median overlap fraction of 0.63 [interquartile range: 0.15-0.93], with similar results for other thresholds. No significant differences were found among overlap fractions of the treatment groups. A high incidence of FDG-uptake in normal lung (grade-1 pneumonitis: 73%) was found post-treatment.
FDG redistributed boosting did not reduce FDG spatial consistency from pre-treatment to post-treatment, which was highly variable among patients. The study found high numbers of patients with lung inflammation after treatment.
FDG-PET 扫描显示 NSCLC 患者在放化疗前后具有空间一致性，提示存在放射抵抗性。我们假设，与已注册患者或升级剂量治疗相比，接受 FDG 再分布剂量涂抹的患者，其空间一致性会降低。
在一项 II 期试验（NCT01024829）中，将 IIB 期不可手术的 NSCLC 患者随机分为两组，一组接受单纯原发肿瘤同源强化放疗，另一组接受 FDG-GTV 亚体积再分布的不均匀强化放疗（FDG-SUV＞50% SUV）。无法强化（≥72Gy）的患者接受 66Gy/24 次分割。采用不同的重叠分数阈值来测量治疗前后（3 个月）FDG-PET 扫描的空间一致性。
66/82 例患者在试验中接受了随机治疗。50% SUV 预处理和 70% SUV 后处理的阈值产生了 0.63 的中位数重叠分数（四分位间距：0.15-0.93），其他阈值也有类似结果。各组之间的重叠分数无显著差异。治疗后发现正常肺 FDG 摄取明显增加（1 级放射性肺炎：73%）。
FDG 再分布强化并未降低治疗前后 FDG 的空间一致性，且患者间的一致性差异较大。研究发现，治疗后大量患者出现肺部炎症。
