Nuclear Medicine Unit, Endocrinology Department, University Hospital in Krakow, Krakow, Poland.
Chair and Department of Endocrinology, Jagiellonian University Medical College, Krakow, Poland.
Front Endocrinol (Lausanne). 2022 Aug 15;13:929391. doi: 10.3389/fendo.2022.929391. eCollection 2022.
Peptide receptor radionuclide therapy (PRRT) is one of the most effective therapeutic options for the treatment of metastatic, well-differentiated neuroendocrine tumors (NETs). It improves progressive disease-free survival and enables the control of hormone secretion in functioning tumors.Currently, there are no clearly established predictors of response to PRRT. The main factors hindering such a prediction are the heterogeneity of somatostatin receptor expression within and between lesions, lack of standardized parameters for functional imaging, and the use of different PRRT protocols.The main goal of our study was to quantify SUVmax changes in [68Ga]Ga-DOTA-TATE PET/CT scans as a potential predictor of long-term response to PRRT.
Out of 20 patients treated with PRRT using [177Lu]Lu and/or [177Lu]Lu/[90Y]Y-DOTA-TATE in 2017-2019 due to dissemination of neuroendocrine neoplasm, 12 patients underwent [68Ga]Ga-DOTA-TATE PET/CT on average 3.1 months before and 4.5 months after PRRT and were eligible for the analysis.In total, 76 NET lesions were evaluated. We measured SUVmax for every lesion in both PET/CT scans (before and after PRRT). Those values were corrected by liver SUVmax and liver SUVmean measured in volumetric analysis and specified as SUVlmax and SUVlmean. As a next step, changes in SUVlmax and SUVlmean were assessed based on both PET/CT scans. Finally, results were correlated with the clinical outcome assessed as progressive disease, disease stabilization, or partial response.
The mean follow-up period was 19.9 months. Progressive disease, partial response, and disease stabilization were found in five, two, and five patients, respectively. Among patients with a partial response, the decrease in mean SUVlmax was 66.3% when compared to baseline. In patients with stable disease, the decrease in SUVlmax was 30.3% when compared to baseline. In patients with progressive disease, the mean increase in SUVlmax was 9.1% when compared to baseline. The changes in SUVlmean were -69,8%, -30.8%, and -3.7%, respectively.
A decrease in the SUVmax value in NET lesions, corrected by normal liver tissue uptake assessed in [68Ga]Ga-DOTA-TATE PET/CT scans, indicates a lower risk for NET progressive disease within 20 months after PRRT and may constitute an additional and independent parameter for the estimation of overall risk for disease progression.
肽受体放射性核素疗法（PRRT）是治疗转移性、分化良好的神经内分泌肿瘤（NETs）的最有效治疗选择之一。它可以改善无进展疾病的生存，并控制功能性肿瘤的激素分泌。目前，对于 PRRT 反应的预测尚无明确的标准。阻碍这种预测的主要因素是肿瘤内和肿瘤间生长抑素受体表达的异质性、功能成像标准化参数的缺乏以及不同 PRRT 方案的应用。我们研究的主要目的是量化[68Ga]Ga-DOTA-TATE PET/CT 扫描中 SUVmax 的变化，作为预测 PRRT 长期反应的潜在指标。
2017 年至 2019 年期间，20 名患有神经内分泌肿瘤播散的患者接受了 PRRT（使用[177Lu]Lu 和/或[177Lu]Lu/[90Y]Y-DOTA-TATE）治疗，其中 12 名患者在 PRRT 前平均 3.1 个月和 PRRT 后 4.5 个月接受了[68Ga]Ga-DOTA-TATE PET/CT，并符合分析条件。总共评估了 76 个 NET 病变。我们在 PET/CT 扫描（PRRT 前后）中测量了每个病变的 SUVmax。通过容积分析中测量的肝 SUVmax 和肝 SUVmean 对这些值进行校正，并指定为 SUVlmax 和 SUVlmean。下一步，根据两次 PET/CT 扫描评估 SUVlmax 和 SUVlmean 的变化。最后，将结果与临床结果（进展性疾病、疾病稳定或部分反应）进行相关性分析。
中位随访时间为 19.9 个月。5 名患者出现进展性疾病，2 名患者出现部分反应，5 名患者出现疾病稳定。在部分反应的患者中，与基线相比，平均 SUVlmax 下降了 66.3%。在疾病稳定的患者中，与基线相比，SUVlmax 下降了 30.3%。在进展性疾病的患者中，与基线相比，SUVlmax 平均增加了 9.1%。SUVlmean 的变化分别为-69.8%、-30.8%和-3.7%。
NET 病变中 SUVmax 值的下降，通过[68Ga]Ga-DOTA-TATE PET/CT 扫描中正常肝组织摄取进行校正，表明 PRRT 后 20 个月内 NET 进展性疾病的风险较低，并且可能成为疾病进展整体风险估计的附加和独立参数。
