Robertson Matthew S, Wang Yating, Cheng SuChun, Park Hyesun, Glomski Shahar, Harshman Lauren C, Pace Amanda, Kilar Jacqueline, Flynn Meredith, Gilbert Lauren, Choudhury Atish D, Jacene Heather
Department of Imaging, Dana-Farber Cancer Institute, Department of Radiology Brigham and Women's Hospital, Boston, MA, 02115, USA.
Division of Biostatistics, Department of Data Science, Dana-Farber Cancer Institute, Boston, MA, USA.
Radiol Med. 2025 Jan;130(1):132-142. doi: 10.1007/s11547-024-01931-7. Epub 2024 Nov 20.
The purpose of this study is to demonstrate the consistency and reproducibility of quantitative SPECT/CT by evaluating the maximum SUV (SUV) in normal bone, to provide the reference value of metastatic lesions, and to evaluate the clinical implication of SUV changes of osseous metastasis during treatment.
This prospective imaging sub-study was performed as part of a phase 2 clinical trial of patients with metastatic castration-resistant prostate cancer (mCRPC) randomized to the combination of pembrolizumab plus radium-223 or to radium-223 alone (NCT03093428). The maximum standardized uptake value (SUV) and mean Hounsfield Unit (HU) of normal bone as well as metastases were measured using a 1.5 cm region of interest (ROI) on CT and xSPECT Quant reconstruction on the baseline study (S) and restaging scans. The most tracer-avid metastatic lesion in each patient on S was selected as a target lesion, and changes of SUV and HU of the target lesion were compared on the first restaging scan (S). Correlations between the percentage changes of SUV of the target lesion with alkaline phosphatase (ALP) and prostate-specific antigen (PSA) were assessed.
Twenty-one patients were enrolled on the imaging sub-study of which 15 had paired baseline S and S data. On S, the median SUV and HU of normal bone was 5.85 g/mL (0.42-14.98) and 133.03 (range, 28.47-461.91), respectively. The median SUV and HU of metastasis were 42.2 g/mL (range, 17.96-143.36) and 549.58 (177.87-1107.64), respectively. There was significant reduction in SUV (- 40.1%, range - 86.2 to + 23.5%), p < 0.001) and increase in HU (+ 8.3%, range - 11.3 to + 61.7%, p = 0.0479, Wilcoxon signed-rank test) of target lesions between S and S. Spearman correlation between the percentage changes of SUV of a target lesion and both serum PSA (r = 0.33, p = 0.226) and ALP (r = 0.45, p = 0.094) were not statistically significant.
Quantitative SPECT/CT provides consistent and objective imaging parameters, which can help monitor tumor burden. The median SUVmax of metastasis at baseline was roughly 7.2-fold higher than normal bone. Quantitative SPECT/CT may help visualize the early osteoblastic treatment response in prostate cancer patients treated with radium-223 alone or combined with pembrolizumab.
本研究旨在通过评估正常骨中的最大标准化摄取值（SUV）来证明定量SPECT/CT的一致性和可重复性，提供转移灶的参考值，并评估骨转移在治疗期间SUV变化的临床意义。
这项前瞻性影像子研究是转移性去势抵抗性前列腺癌（mCRPC）患者2期临床试验的一部分，患者被随机分为帕博利珠单抗联合镭-223或单独使用镭-223（NCT03093428）。在基线研究（S）和再分期扫描中，使用1.5 cm的感兴趣区（ROI）在CT上测量正常骨以及转移灶的最大标准化摄取值（SUV）和平均亨氏单位（HU），并进行xSPECT Quant重建。选择每位患者在S期时放射性示踪剂摄取最高的转移灶作为靶病灶，并在首次再分期扫描（S）时比较靶病灶的SUV和HU变化。评估靶病灶SUV百分比变化与碱性磷酸酶（ALP）和前列腺特异性抗原（PSA）之间的相关性。
21例患者纳入了影像子研究，其中15例有配对的基线S期和S期数据。在S期，正常骨的SUV中位数为5.85 g/mL（0.42 - 14.98），HU中位数为133.03（范围28.47 - 461.91）。转移灶的SUV中位数为42.2 g/mL（范围17.96 - 143.36），HU中位数为549.58（177.87 - 1107.64）。在S期和S期之间，靶病灶的SUV显著降低（-40.1%，范围-86.2至+23.5%，p < 0.001），HU升高（+8.3%，范围-11.3至+61.7%，p = 0.0479，Wilcoxon符号秩检验）。靶病灶SUV百分比变化与血清PSA（r = 0.33，p = 0.226）和ALP（r = 0.45，p = 0.094）之间的Spearman相关性无统计学意义。
定量SPECT/CT提供了一致且客观的影像参数，有助于监测肿瘤负荷。基线时转移灶的SUVmax中位数比正常骨高约7.2倍。定量SPECT/CT可能有助于直观显示单独使用镭-223或联合帕博利珠单抗治疗的前列腺癌患者的早期成骨治疗反应。
