Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden.
Department of Medical Radiation Physics and Nuclear Medicine, Karolinska University Hospital, Huddinge, Sweden.
J Nucl Med. 2023 Aug;64(8):1232-1237. doi: 10.2967/jnumed.123.265481. Epub 2023 Jun 22.
Correct and timely diagnosis of pancreatic cancer (PC) is essential for treatment selection but is still clinically challenging. Standard-of-care imaging methods can sometimes not differentiate malignancies from inflammatory lesions or detect malignant transformation in premalignant lesions. This interim analysis of a prospective clinical trial aimed to evaluate the diagnostic accuracy of [Ga]fibroblast activation protein inhibitor (FAPI)-46 PET/CT for PC and determine the sample size needed to demonstrate whether this imaging technique improves the characterization of equivocal lesions detected by standard-of-care imaging methods. [Ga]FAPI-46 PET/CT imaging was performed on 30 patients scheduled for surgical resection of suspected PC. Target lesions were delineated, SUV and SUV were determined, and the results were compared with those of standard-of-care imaging. Receiver operating characteristics were calculated for the whole cohort and a subcohort of 11 patients with an equivocal clinical imaging work-up preoperatively. Postoperative histopathologic findings served as a reference standard, and the statistical power was determined. Histopathologic examination revealed malignancy in 20 patients and benign lesions in 10 patients. Significantly elevated [Ga]FAPI-46 uptake was observed in malignant tumors compared with benign lesions ( < 0.001). Receiver-operating-characteristic analyses established optimal cutoffs for both SUVs for differentiation of malignant from nonmalignant pancreatic tumors. The optimal SUV cutoff was 10.2 and showed 95% sensitivity and 80% specificity for the whole cohort, as well as 100% diagnostic accuracy when considering the subcohort with equivocal imaging work-up only. For sufficient statistical power, 38 equivocal observations are needed. We conclude that [Ga]FAPI-46 PET/CT can accurately differentiate malignant from benign pancreatic lesions deemed equivocal by standard-of-care imaging. This trial will therefore continue to recruit a total of 120 patients to reach those 38 equivocal observations needed for sufficient statistical power. On the basis of our findings, we propose that [Ga]FAPI-46 PET/CT not only can be clinically applied as a complement but also could become a necessary tool when standard-of-care imaging is inconclusive.
正确且及时地诊断胰腺癌（PC）对于治疗选择至关重要，但在临床上仍具有挑战性。标准护理成像方法有时无法将恶性肿瘤与炎症性病变区分开来，或在癌前病变中检测到恶性转化。这项前瞻性临床试验的中期分析旨在评估[Ga]成纤维细胞激活蛋白抑制剂（FAPI）-46 PET/CT 对 PC 的诊断准确性，并确定需要的样本量，以证明这种成像技术是否能改善标准护理成像方法检测到的可疑病变的特征。[Ga]FAPI-46 PET/CT 成像在 30 名计划接受疑似 PC 手术切除的患者中进行。对靶病变进行了描绘，确定了 SUV 和 SUV，并将结果与标准护理成像的结果进行了比较。对整个队列和术前临床影像学检查结果不确定的 11 名患者的亚队列进行了受试者工作特征分析。术后组织病理学检查结果作为参考标准，并确定了统计效力。组织病理学检查显示 20 名患者为恶性肿瘤，10 名患者为良性病变。与良性病变相比，恶性肿瘤中[Ga]FAPI-46 的摄取明显升高（<0.001）。受试者工作特征分析确定了区分恶性和非恶性胰腺肿瘤的 SUV 的最佳截断值。对于整个队列，最佳 SUV 截断值为 10.2，具有 95%的敏感性和 80%的特异性，仅考虑影像学检查结果不确定的亚队列时，诊断准确率为 100%。为了达到足够的统计效力，需要 38 个不确定的观察结果。我们得出结论，[Ga]FAPI-46 PET/CT 能够准确地区分标准护理成像认为不确定的恶性和良性胰腺病变。因此，该试验将继续招募总共 120 名患者，以获得足够的统计效力所需的 38 个不确定观察结果。基于我们的研究结果，我们提出[Ga]FAPI-46 PET/CT 不仅可以作为一种补充手段应用于临床，而且在标准护理成像结果不确定时，也可以成为一种必要的工具。
