MedAustron Ion Therapy Center, Marie Curie-Straße 5, 2700, Wiener Neustadt, Austria.
Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
Strahlenther Onkol. 2023 Apr;199(4):396-403. doi: 10.1007/s00066-022-02010-4. Epub 2022 Oct 19.
Overexpression of the somatostatin receptor (SSTR) has led to adoption of SSTR PET/CT for diagnosis and radiotherapy planning in meningioma, but data on SSTR expression during follow-up remain scarce. We investigated PET/CT quantifiers of SSTR tracers in WHO grade I meningioma following fractionated proton beam therapy (PBT) compared to standard response assessment with MRI.
Twenty-two patients diagnosed with low-grade meningioma treated by PBT were included. Follow-up included clinical visits, MRI, and [Ga]Ga-DOTATOC PET/CT scans. Radiologic tumor response, MRI and PET volume (V and V), maximum and mean standardied uptake value (SUVmax/SUVmean), total lesion activity (TLA), and heterogeneity index (HI) were evaluated.
Median follow-up was 35.3 months (range: 6.4-47.9). Nineteen patients (86.4%, p = 0.0009) showed a decrease of SUVmax between baseline and first follow-up PET/CT (median: -24%, range: -53% to +89%) and in 81.8% of all cases, the SUVmax, SUVmean, and TLA at last follow-up were eventually lower than at baseline (p = 0.0043). Ambiguous trends without significance between the timepoints analyzed were observed for V. HI increased between baseline and last follow-up in 75% of cases (p = 0.024). All patients remained radiologically and clinically stable. Median V decreased by -9.3% (range 0-32.5%, p < 0.0001) between baseline and last follow-up.
PET/CT in follow-up of irradiated meningioma showed an early trend towards decreased binding of SSTR-specific tracers following radiation and MRI demonstrated consistently stable or decreasing tumor volume. Translational research is needed to clarify the underlying biology of the subsequent increase in SSTR PET quantifiers.
生长抑素受体（SSTR）的过度表达导致 SSTR PET/CT 用于脑膜瘤的诊断和放疗计划，但关于 SSTR 在随访期间表达的数据仍然很少。我们研究了与 MRI 标准反应评估相比，在接受分次质子束治疗（PBT）的 I 级脑膜瘤患者中，SSTR 示踪剂的 PET/CT 定量指标。
纳入 22 例经 PBT 治疗的低级别脑膜瘤患者。随访包括临床检查、MRI 和 [Ga]Ga-DOTATOC PET/CT 扫描。评估了放射学肿瘤反应、MRI 和 PET 体积（V 和 V）、最大和平均标准化摄取值（SUVmax/SUVmean）、总病变活性（TLA）和异质性指数（HI）。
中位随访时间为 35.3 个月（范围：6.4-47.9）。19 例患者（86.4%，p=0.0009）在基线和第一次随访 PET/CT 之间 SUVmax 下降（中位数：-24%，范围：-53%至+89%），在所有病例中，81.8%的 SUVmax、SUVmean 和 TLA 在最后一次随访时最终低于基线（p=0.0043）。分析的各时间点之间观察到 V 呈混杂趋势但无显著意义。在 75%的病例中，HI 在基线和最后一次随访之间增加（p=0.024）。所有患者均保持影像学和临床稳定。中位 V 在基线和最后一次随访之间减少了-9.3%（范围 0-32.5%，p<0.0001）。
在接受放疗的脑膜瘤的随访中，SSTR 特异性示踪剂的结合在放疗后显示出早期下降的趋势，而 MRI 显示肿瘤体积持续稳定或减少。需要进行转化研究以阐明 SSTR PET 定量指标随后增加的潜在生物学机制。
