Ceci Francesco, Bianchi Lorenzo, Borghesi Marco, Polverari Giulia, Farolfi Andrea, Briganti Alberto, Schiavina Riccardo, Brunocilla Eugenio, Castellucci Paolo, Fanti Stefano
Metropolitan Nuclear Medicine, S.Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
Nuclear Medicine, AOU Città della Salute e della Scienza di Torino, Department of Medical Sciences, University of Turin, Corso AM Dogliotti, 14, 10129, Turin, Italy.
Eur J Nucl Med Mol Imaging. 2020 Jan;47(1):136-146. doi: 10.1007/s00259-019-04505-2. Epub 2019 Sep 6.
The objective of this study was to develop a clinical nomogram to predict gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography (Ga-PSMA-11-PET/CT) positivity in different clinical settings of PSA failure.
Seven hundred three (n = 703) prostate cancer (PCa) patients with confirmed PSA failure after radical therapy were enrolled. Patients were stratified according to different clinical settings (first-time biochemical recurrence [BCR]: group 1; BCR after salvage therapy: group 2; biochemical persistence after radical prostatectomy [BCP]: group 3; advanced-stage PCa before second-line systemic therapies: group 4). First, we assessed Ga-PSMA-11-PET/CT positivity rate. Second, multivariable logistic regression analyses were used to determine predictors of positive scan. Third, regression-based coefficients were used to develop a nomogram predicting positive Ga-PSMA-11-PET/CT result and 200 bootstrap resamples were used for internal validation. Fourth, receiver operating characteristic (ROC) analysis was used to identify the most informative nomogram's derived cutoff. Decision curve analysis (DCA) was implemented to quantify nomogram's clinical benefit.
Ga-PSMA-11-PET/CT overall positivity rate was 51.2%, while it was 40.3% in group 1, 54% in group 2, 60.5% in group 3, and 86.9% in group 4 (p < 0.001). At multivariable analyses, ISUP grade, PSA, PSA doubling time, and clinical setting were independent predictors of a positive scan (all p ≤ 0.04). A nomogram based on covariates included in the multivariate model demonstrated a bootstrap-corrected accuracy of 82%. The nomogram-derived best cutoff value was 40%. In DCA, the nomogram revealed clinical net benefit of > 10%.
This novel nomogram proved its good accuracy in predicting a positive scan, with values ≥ 40% providing the most informative cutoff in counselling patients to Ga-PSMA-11-PET/CT. This tool might be important as a guide to clinicians in the best use of PSMA-based PET imaging.
本研究的目的是开发一种临床列线图，以预测在不同前列腺特异性抗原（PSA）失败临床情况下镓-68前列腺特异性膜抗原正电子发射断层扫描/计算机断层扫描（Ga-PSMA-11-PET/CT）的阳性结果。
纳入703例根治性治疗后确诊PSA失败的前列腺癌（PCa）患者。根据不同临床情况对患者进行分层（首次生化复发[BCR]：第1组；挽救性治疗后BCR：第2组；根治性前列腺切除术后生化持续存在[BCP]：第3组；二线全身治疗前的晚期PCa：第4组）。首先，我们评估Ga-PSMA-11-PET/CT阳性率。其次，采用多变量逻辑回归分析确定扫描阳性的预测因素。第三，使用基于回归的系数开发预测Ga-PSMA-11-PET/CT阳性结果的列线图，并使用200次自抽样重采样进行内部验证。第四，采用受试者工作特征（ROC）分析确定列线图中最具信息量的临界值。实施决策曲线分析（DCA）以量化列线图的临床益处。
Ga-PSMA-11-PET/CT总体阳性率为51.2%，第1组为40.3%，第2组为54%，第3组为60.5%，第4组为86.9%（p<0.001）。在多变量分析中，国际泌尿病理学会（ISUP）分级、PSA、PSA倍增时间和临床情况是扫描阳性的独立预测因素（所有p≤0.04）。基于多变量模型中纳入的协变量的列线图显示自抽样校正后的准确率为82%。列线图得出的最佳临界值为40%。在DCA中，列线图显示临床净益处>10%。
这种新型列线图在预测扫描阳性方面显示出良好的准确性，值≥40%为向患者咨询Ga-PSMA-11-PET/CT提供了最具信息量的临界值。作为指导临床医生最佳使用基于PSMA的PET成像的工具，该工具可能具有重要意义。
