Aim

qPET is a quantitative method used to assess FDG-PET response in lymphoma. qPET was developed using 898 scans from children with Hodgkin Lymphoma (HL) in the EuroNet-PHL-C1 (C1) trial. The aim of this study was to determine if qPET could be applied as an alternative response method in adults in the RAPID trial.

Methods

PET-CT scans performed after 3 cycles of ABVD in RAPID were re-evaluated by an independent reader, blinded to PET results and outcome in RAPID. All initially involved regions were assessed visually and by qPET. The distribution of qPET measurements was compared for RAPID and C1 patients. Previously published qPET thresholds corresponding to visual DS (vDS) of 1–5 in C1 were used to derive quantitative DS (qDS) for RAPID patients.

Results

PET-CT scans were available for 450 patients from RAPID. vDS were 1 (171 scans), 2 (153 scans), 3 (72 scans), 4 (31 scans) and 5 (23 scans) respectively. The distribution of qPET values was similar to C1 patients, with a unimodal ‘normal’ distribution and a long tail to the right, suggestive of favorable response in the majority and less favorable response in the minority with outlying values. qPET thresholds from C1 applied in RAPID patients gave 86% concordance for vDS and qDS. There was 97% concordance for complete metabolic response (CMR; DS 1–3) vs. no-CMR using the Lugano classification.

Conclusion

qPET which was developed in pediatric patients receiving more intensive OEPA chemotherapy, was a suitable quantitative method for assessing response in adult patients treated with ABVD in a response-adapted setting in the RAPID trial.

中文翻译：

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霍奇金淋巴瘤临时PET的定量评估：RAPID试验中成年患者qPET方法的评估。

目标

qPET是用于评估淋巴瘤中FDG-PET反应的定量方法。EuroPET-PHL-C1（C1）试验使用来自霍奇金淋巴瘤（HL）儿童的898次扫描开发了qPET。这项研究的目的是确定是否可以将qPET用作RAPID试验中成人的替代反应方法。

方法

独立阅读器重新评估了RAPID中ABVD 3个周期后进行的PET-CT扫描，对PET结果和RAPID中的结果不了解。通过视觉和qPET评估所有最初涉及的区域。比较了RAPID和C1患者的qPET测量值分布。先前发布的qPET阈值对应于C1中的视觉DS（vDS）1-5，用于得出RAPID患者的定量DS（qDS）。

结果

PET-CT扫描可用于RAPID的450例患者。vDS分别为1（171次扫描），2（153次扫描），3（72次扫描），4（31次扫描）和5（23次扫描）。qPET值的分布与C1患者相似，具有单峰的“正态”分布，右侧长尾巴，表明多数患者的反应良好，而少数患者的反应较差。来自RAPID患者的C1的qPET阈值对vDS和qDS的一致性为86％。使用卢加诺分类法，完全代谢反应（CMR; DS 1-3）与非CMR的一致性为97％。

结论

qPET是在接受更深入的OEPA化疗的儿科患者中开发的，是一种评估RAPID试验中适应性强的接受ABVD治疗的成年患者的适应性定量方法。