Objective: The increasing use of PSMA-PET/CT for restaging prostate cancer (PCa) leads to a patient shift from a non-metastatic situation based on conventional imaging (CI) to a metastatic situation. Since established therapeutic pathways have been designed according to CI, it is unclear how this should be translated to the PSMA-PET/CT results. This study aimed to investigate whether PSMA-PET/CT and clinical parameters could predict the visibility of PSMA-positive lesions on a bone scan (BS). Methods: In four different centers, all PCa patients with BS and PSMA-PET/CT within 6 months without any change in therapy or significant disease progression were retrospectively selected. Up to 10 non-confluent clear bone metastases were selected per PSMA-PET/CT and SUVmax, SUVmean, PSMAtot, PSMAvol, density, diameter on CT, and presence of cortical erosion were collected. Clinical variables (age, PSA, Gleason Score) were also considered. Two experienced double-board physicians decided whether a bone metastasis was visible on the BS, with a consensus readout for discordant findings. For predictive performance, a random forest was fit on all available predictors, and its accuracy was assessed using 10-fold cross-validation performed 10 times. Results: A total of 43 patients were identified with 222 bone lesions on PSMA-PET/CT. A total of 129 (58.1%) lesions were visible on the BS. In the univariate analysis, all PSMA-PET/CT parameters were significantly associated with the visibility on the BS (p< 0.001). The random forest reached a mean accuracy of 77.6% in a 10-fold cross-validation. Conclusions: These preliminary results indicate that there might be a way to predict the BS results based on PSMA-PET/CT, potentially improving the comparability between both examinations and supporting decisions for therapy selection.
目的：PSMA-PET/CT在前列腺癌（PCa）再分期中的应用日益增多，导致部分患者基于传统影像学（CI）判定的非转移状态转变为转移状态。由于既定的治疗路径是根据传统影像学结果设计的，目前尚不清楚应如何将此类路径转化应用于PSMA-PET/CT的检测结果。本研究旨在探讨PSMA-PET/CT参数及临床指标能否预测PSMA阳性病灶在骨扫描（BS）中的显影情况。方法：回顾性筛选四家医疗中心中同时接受骨扫描与PSMA-PET/CT检查（间隔不超过6个月）且治疗无变更、病情无显著进展的前列腺癌患者。针对每例PSMA-PET/CT检查，选取最多10个非融合性明确骨转移灶，记录其SUVmax、SUVmean、PSMAtot、PSMAvol、CT密度、CT直径及骨皮质侵蚀情况等参数，同时收集年龄、PSA、格里森评分等临床变量。由两位经验丰富的双资质医师判定骨转移灶在骨扫描中的显影状态，对不一致结果进行协商达成共识。采用随机森林模型整合所有预测变量，通过10次重复的10折交叉验证评估预测效能。结果：共纳入43例患者，PSMA-PET/CT检测出222处骨转移灶，其中129处（58.1%）在骨扫描中显影。单因素分析显示所有PSMA-PET/CT参数均与骨扫描显影状态显著相关（p<0.001）。随机森林模型在10折交叉验证中平均准确率达77.6%。结论：这些初步结果表明，基于PSMA-PET/CT参数预测骨扫描结果具有可行性，可能提升两种检查结果的可比性，并为治疗方案选择提供决策支持。
Can We Predict Skeletal Lesion on Bone Scan Based on Quantitative PSMA PET/CT Features?
肿瘤(癌症)患者之家