Comparison of the Impact of 68Ga-DOTATATE and 18F-FDG PET/CT on Clinical Management in Patients with Neuroendocrine Tumors.
This study aimed to assess the clinical impact of 68Ga-DOTATATE and 18F-FDG with respect to the management plan and to evaluate the prognostic value of both tracers.
A total of 104 patients (55 male and 49 female; median age, 58 y; range, 20-90 y) with histologically proven neuroendocrine tumors (NETs) underwent both 68Ga-DOTATATE and 18F-FDG PET/CT. Twenty-eight patients (26.9%) had poorly differentiated tumors, and 76 (73.1%) had well-differentiated tumors. PET/CT results and SUVs were compared with prognostic factors such as histologic grade (G1, G2, or G3, for low-grade [well differentiated], intermediate-grade [moderately differentiated], and high-grade [poorly differentiated], respectively), chromogranin A, and proliferation index (Ki-67).
The 68Ga-DOTATATE and 18F-FDG PET/CT findings were discordant in 65 patients (62.5%) and concordant in 39 patients (37.5%). The results changed the therapeutic plan in 84 patients (80.8%). In 22 patients (21.1%), decision making was based on the 18F-FDG findings; in 32 (30.8%), on the findings with both radiotracers; and in 50 (48.1%), on the 68Ga-DOTATATE findings. The most frequent management decision based on 18F-FDG was initiation of chemotherapy (10 patients, 47.6%). The most common treatment decision due to 68Ga-DOTATATE was initiation of peptide receptor radionuclide therapy (14 patients, 27.4%). In 11 (39.2%) of 28 patients with poorly differentiated NETs, the management decision was based on only the 18F-FDG results. For 68Ga-DOTATATE, SUVmax was higher for G1 tumors and lower for G3 tumors (P = 0.012). However, no significant differences in 18F-FDG-derived SUVs were observed between different grades (P = 0.38). The Mann-Whitney test showed significant differences in 68Ga-DOTATATE SUVmax between tumors with a Ki-67 of less than 5% and tumors with a Ki-67 of more than 5% (P = 0.004), without significance differences in 18F-FDG SUVmax Log-rank analysis showed statistically significant differences in survival for patients with bone metastasis versus soft-tissue or no metastasis for both 18F-FDG (P = 0.037) and 68Ga-DOTATATE (P = 0.047). Overall survival declined rapidly with increasing grade (P = 0.001), at an estimated 91 mo for G1, 59 mo for G2, and 48 mo for G3.
18F-FDG PET/CT had no clinical impact on G1 NETs and a moderate impact on G2 NETs. However, in poorly differentiated NETs, 18F-FDG PET/CT plays a significant clinical role in combination with 68Ga-DOTATATE. 68Ga DOTATATE SUVmax relates to grade and Ki-67 and can be used prognostically.
Panagiotidis E
，Alshammari A
，Michopoulou S
，Skoura E
，Naik K
，Maragkoudakis E
，Mohmaduvesh M
，Al-Harbi M
，Belda M
，Caplin ME
，Toumpanakis C
，Bomanji J
... -
《-》
MIB-1 Index-Stratified Assessment of Dual-Tracer PET/CT with (68)Ga-DOTATATE and (18)F-FDG and Multimodality Anatomic Imaging in Metastatic Neuroendocrine Tumors of Unknown Primary in a PRRT Workup Setting.
Our aim was to comparatively assess dual-tracer PET/CT (68Ga-DOTATATE and 18F-FDG) and multimodality anatomic imaging in studying metastatic neuroendocrine tumors (NETs) of unknown primary (CUP-NETs) scheduled for peptide receptor radionuclide therapy for divergence of tracer uptake on dual-tracer PET/CT, detection of primary, and overall lesion detection vis-a-vis tumor proliferation index (MIB-1/Ki-67). Methods: Fifty-one patients with CUP-NETs (25 men, 26 women; age, 22-74 y), histopathologically proven and thoroughly investigated with conventional imaging modalities (ultrasonography, CT/contrast-enhanced CT, MRI, and endoscopic ultrasound, wherever applicable), were retrospectively analyzed. Patients were primarily referred for deciding on feasibility of peptide receptor radionuclide therapy (except 2 patients), and all had undergone 68Ga-DOTATATE and 18F-FDG PET/CT as part of pretreatment workup. The sites of metastases included liver, lung/mediastinum, skeleton, abdominal nodes, and other soft-tissue sites. Patients were divided into 5 groups on the basis of MIB-1/Ki-67 index on a 5-point scale: group I (1%-5%) (n = 35), group II (6%-10%) (n = 8), group III (11%-15%) (n = 4), group IV (16%-20%) (n = 2), and group V (>20%) (n = 2). Semiquantitative analysis of tracer uptake was undertaken by SUVmax of metastatic lesions and the primary (when detected). The SUVmax values were studied over increasing MIB-1/Ki-67 index. The detection sensitivity of 68Ga-DOTATATE for primary and metastatic lesions was assessed and compared with other imaging modalities including 18F-FDG PET/CT. Results: Unknown primary was detected on 68Ga-DOTATATE in 31 of 51 patients, resulting in sensitivity of 60.78% whereas overall lesion detection sensitivity was 96.87%. The overall lesion detection sensitivities (individual groupwise from group I to group V) were 97.75%, 87.5%, 100%, 100%, and 66.67%, respectively. As MIB-1/Ki-67 index increased, 68Ga-DOTATATE uptake decreased in metastatic and primary lesions (mean SUVmax, 43.5 and 22.68 g/dL in group I to 22.54 and 16.83 g/dL in group V, respectively), whereas 18F-FDG uptake showed a gradual rise (mean SUVmax, 3.66 and 2.86 g/dL in group I to 7.53 and 9.58 g/dL in group V, respectively). There was a corresponding decrease in the 68Ga-DOTATATE-to-18F-FDG uptake ratio with increasing MIB-1/Ki-67 index (from 11.89 in group I to 2.99 in group V). Conclusion: In CUP-NETs, the pattern of uptake on dual-tracer PET (68Ga-DOTATATE and 18F-FDG) correlates well with tumor proliferation index with a few outliers; combined dual-tracer PET/CT with MIB-1/Ki-67 index would aid in better whole-body assessment of tumor biology in CUP-NETs.
Sampathirao N
，Basu S
《-》
ResearchGate
(全网免费下载)
钛学术
(全网免费下载)
