■准确,及时地预测胃肠道间质瘤(GIST)对靶向治疗的反应对于优化治疗策略至关重要。然而,复发或转移性GIST的一些部分表现为非FDG-aid病变,在治疗评估中限制[18F]氟脱氧葡萄糖正电子发射断层扫描/计算机断层扫描([18F]FDGPET/CT)的值。这项研究评估了[18F]F-成纤维细胞激活蛋白抑制剂(FAPI)-42[18F]FAPI-42)PET/CT用于评估复发或转移性GIST的治疗反应的功效,与[18F]FDGPET/CT进行比较,并探索了一种集成PET/CT成像和临床参数的模型,以优化这些诊断工具的临床使用。
■我们的回顾性分析包括27例复发或转移性GIST患者,这些患者在切换靶向治疗前基线时接受了[18F]FAPI-42PET/CT和[18F]FDGPET/CT。根据6个月时的对比增强计算机断层扫描(CT)扫描,根据实体瘤反应标准(RECIST)1.1将治疗反应状态分为进展组(PG)和非进展组(NPG)。[18F]FAPI-42和[18F]FDGPET/CT参数,包括平均标准化摄取值(SUVmean),根据瘦体重校正的标准摄取值(SULpeak),最大标准化摄取值(SUVmax),肿瘤血池SUV比(TBR),肿瘤与肝脏SUV比率(TLR),代谢性肿瘤体积(MTV)/FAPI阳性肿瘤体积(GTV-FAPI),总病变糖酵解(TLG)/FAPI阳性总病变累积(TLF)与应答状态相关,以确定治疗应答的指示.通过生成受试者工作特征曲线(ROC)来量化它们的预测性能,校正曲线,和交叉验证。
■27例患者共发现110个病灶。与PG相比,NPG与FDGPET/CT中TBR和SUVmean的较低水平相关(TBR-FDG,SUVmean-FDG;分别为P=0.033和P=0.038),FAPIPET/CT中具有较高的SULpeak和TLF(SULpeak-FAPI,TLF-FAPI;分别为P=0.10和P=0.049)。复合参数模型的预测能力,包括TBR-FDG,SULpeak-FAPI,基因突变,和靶向治疗类型[曲线下面积(AUC)=0.865],优于加入TBR-FDG的少数参数模型(AUC=0.637,P<0.001),SULpeak-FAPI(AUC=0.665,P<0.001)或两者(AUC=0.721,P<0.001)。
■[18F]FAPI-42PET/CT和[18F]FDGPET/CT均具有预测复发或转移性GIST治疗反应的价值。当与[18F]FDGPET/CT组合使用时,[18F]FAPI-42PET/CT提供协同价值。值得注意的是,从包含[18F]FAPI-42PET/CT的模型生成的列线图,[18F]FDGPET/CT参数,基因突变,和靶向治疗的类型可以对复发性转移性GIST的反应产生更精确的预测。
UNASSIGNED: Accurately and promptly predicting the response of gastrointestinal stromal tumors (GISTs) to targeted therapy is essential for optimizing treatment strategies. However, some fractions of recurrent or metastatic GISTs present as non-FDG-avid lesions, limiting the value of [18F]fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) in treatment evaluation. This study evaluated the efficacy of [18F]F-fibroblast activation protein inhibitor (FAPI)-42 [18F]FAPI-42) PET/CT for assessing the treatment response in recurrent or metastatic GISTs, in comparison to [18F]FDG PET/CT and explores a model integrating PET/CT imaging and clinical parameters to optimize the clinical use of these diagnostic tools.
UNASSIGNED: Our retrospective analysis included 27 patients with recurrent or metastatic GISTs who underwent [18F]FAPI-42 PET/CT and [18F]FDG PET/CT at baseline before switching targeted therapy. Treatment response status was divided into a progression group (PG) and a non-progression group (NPG) based on the Response Criteria in Solid Tumors (RECIST) 1.1, according to the contrast-enhanced computed tomography (CT) scan at six months. [18F]FAPI-42 and [18F]FDG PET/CT parameters including the mean standardized uptake value (SUVmean), the standard uptake value corrected for lean body mass (SULpeak), the maximum standardized uptake value (SUVmax), tumor-to-blood pool SUV ratio (TBR), tumor-to-liver SUV ratio (TLR), metabolic tumor volume (MTV)/FAPI-positive tumor volume (GTV-FAPI), total lesion glycolysis (TLG)/FAPI-positive total lesion accumulation (TLF) were correlated with the response status to identify indicative of treatment response. The predictive performance of them was quantified by generating receiver operating characteristic curves (ROC), calibration curves, and cross-validation.
UNASSIGNED: A total of 110 lesions were identified in 27 patients. Compared with PG, NPG was associated with lower levels of TBR and SUVmean in FDG PET/CT (TBR-FDG, SUVmean-FDG; P=0.033 and P=0.038, respectively), with higher SULpeak and TLF in FAPI PET/CT (SULpeak-FAPI, TLF-FAPI; P=0.10 and P=0.049, respectively). The predictive power of a composite-parameter model, including TBR-FDG, SULpeak-FAPI, gene mutation, and type of targeted therapy [area under the curve (AUC) =0.865], was superior to the few-parameter models incorporating TBR-FDG (AUC =0.637, P<0.001), SULpeak-FAPI (AUC =0.665, P<0.001) or both (AUC =0.721, P<0.001).
UNASSIGNED: Both [18F]FAPI-42 PET/CT and [18F]FDG PET/CT have value in predicting the treatment response of recurrent or metastatic GISTs. And [18F]FAPI-42 PET/CT offers synergistic value when used in combination with [18F]FDG PET/CT. Notably, the nomogram generated from the model incorporating [18F]FAPI-42 PET/CT, [18F]FDG PET/CT parameters, gene mutation, and type of targeted therapy could yield more precise predictions of the response of recurrent metastatic GISTs.