Our objective is to explore quantitative imaging markers for early prediction of treatment response in patients with gastroenteropancreatic neuroendocrine tumors (GEP-NETs) undergoing [¹⁷⁷Lu]Lu-DOTATATE therapy. By doing so, we aim to enable timely switching to more effective therapies in order to prevent time-resource waste and minimize toxicities. Methods: Patients diagnosed with unresectable or metastatic, progressive, well-differentiated, receptor-positive GEP-NETs who received 4 sessions of [¹⁷⁷Lu]Lu-DOTATATE were retrospectively selected. Using SPECT/CT images taken at the end of treatment sessions, we counted all visible tumors and measured their largest diameters to calculate the tumor burden score (TBS). Up to 4 target lesions were selected and semiautomatically segmented. Target lesion peak counts and spleen peak counts were measured, and normalized peak counts were calculated. Changes in TBS (ΔTBS) and changes in normalized peak count (ΔnPC) throughout treatment sessions in relation to the first treatment session were calculated. Treatment responses were evaluated using third-month CT and were binarized as progressive disease (PD) or non-PD. Results: Twenty-seven patients were included (7 PD, 20 non-PD). Significant differences were observed in ΔTBS_second-first, ΔTBS_third-first, and ΔTBS_fourth-first (where second-first, third-first, and fourth-first denote scan number between the second and first, third and first, and fourth and first [¹⁷⁷Lu]Lu-DOTATATE treatment cycles), respectively) between the PD and non-PD groups (median, 0.043 vs. −0.049, 0.08 vs. −0.116, and 0.109 vs. −0.123 [P = 0.023, P = 0.002, and P < 0.001], respectively). ΔnPC_second-first showed significant group differences (mean, −0.107 vs. −0.282; P = 0.033); ΔnPC_third-first and ΔnPC_fourth-first did not reach statistical significance (mean, −0.122 vs. −0.312 and −0.183 vs. −0.405 [P = 0.117 and 0.067], respectively). At the optimal threshold, ΔTBS_fourth-first exhibited an area under the curve (AUC) of 0.957, achieving 100% sensitivity and 80% specificity. ΔTBS_second-first and ΔTBS_third-first reached AUCs of 0.793 and 0.893, sensitivities of 71.4%, and specificities of 85% and 95%, respectively. ΔnPC_second-first, ΔnPC_third-first, and ΔnPC_fourth-first showed AUCs of 0.764, 0.693, and 0.679; sensitivities of 71.4%, 71.4%, and 100%; and specificities of 75%, 70%, and 35%, respectively. Conclusion: ΔTBS and ΔnPC can predict [¹⁷⁷Lu]Lu-DOTATATE response by the second treatment session.

我们的目标是探索定量成像标志物，用于早期预测接受 [¹⁷⁷Lu]Lu-DOTATATE 治疗的胃肠胰神经内分泌肿瘤 （GEP-NETs） 患者的治疗反应。通过这样做，我们的目标是能够及时切换到更有效的疗法，以防止时间资源浪费并最大限度地减少毒性。方法：回顾性选择诊断为不可切除或转移性、进行性、分化良好、受体阳性 GEP-NETs 且接受 4 次 [¹⁷⁷Lu]Lu-DOTATATE 治疗的患者。使用治疗结束时拍摄的 SPECT/CT 图像，我们计算了所有可见的肿瘤并测量了它们的最大直径以计算肿瘤负荷评分 （TBS）。选择多达 4 个目标病灶并半自动分割。测量目标病灶峰计数和脾脏峰计数，并计算归一化峰计数。计算与第一次治疗相关的整个治疗过程中 TBS （ΔTBS） 的变化和归一化峰计数 （ΔnPC） 的变化。使用第 3 个月的 CT 评估治疗反应，并将其分为疾病进展 （PD） 或非 PD。结果：纳入 27 例患者 （7 例 PD，20 例非 PD）。在 PD 组和非 PD 组之间观察到 ΔTBS_第二优先、ΔTBS_第三优先和 ΔTBS_第四优先（其中第二第一、第三和第四第一分别表示第二和第一、第三和第一以及第四和第一 [¹⁷⁷Lu]Lu-DOTATATE 治疗周期之间的扫描次数）（中位数，0.043 vs. -0.049、0.08 vs. -0.116 和 0.109 vs. -0.123 [P = 0.023， P = 0.002，P < 0。001]。ΔnPC_第二优先显示显著的组差异（平均值，-0.107 vs. -0.282;P = 0.033）;ΔnPC_第三优先和 ΔnPC_第四优先没有达到统计学意义（平均值分别为 -0.122 对 -0.312 和 -0.183 对 -0.405 [P = 0.117 和 0.067]）。在最佳阈值下，ΔTBS_第四优先的曲线下面积 （AUC） 为 0.957，实现了 100% 的敏感性和 80% 的特异性。ΔTBS_第二优先和 ΔTBS_第三优先达到 AUC 为 0.793 和 0.893，敏感性为 71.4%，特异性分别为 85% 和 95%。ΔnPC_第二优先、ΔnPC_第三优先和 ΔnPC_第四优先显示 AUC 为 0.764、0.693 和 0.679;敏感性为 71.4%、71.4% 和 100%;特异性分别为 75% 、 70% 和 35%。结论： ΔTBS 和 ΔnPC 可以预测第二次治疗时 [¹⁷⁷Lu]Lu-DOTATATE 的反应。