Differences in negative predictive value of prostate MRI based in men with suspected or known cancer

Abstract Objective: To compare the negative predictive value (NPV) of multiparametric MRI for Gleason score (GS) ≥ 3+4 cancer and evaluate predictors of these tumors in men with suspected disease and under active surveillance (AS). Materials and Methods: This retrospective study included 38 men with suspected prostate cancer and 38 under AS with scans assigned PI-RADS v2 scores 1 or 2 between May 2016 and September 2017. Biopsy results were no cancer, GS = 3+3, or GS ≥ 3+4. Pre-MRI PSA, gland volume, and PSA density were recorded. Chi-square, equality of proportions, and logistic regressions were used to analyze the data. Results: Intermediate to high-grade cancer was found in 12.8% (95% CI = 2.3-23.3) and 35.9% (95% CI = 20.8-50.9) of men with suspected cancer, and under AS (p = 0.02), respectively. The NPV for GS ≥ 3+4 were 87.2% (suspected cancer; 76.7-97.7) and 64.1% (AS; 49.0-79.2). In neither group PSA significantly predicted cancer grade (p = 0.75 and 0.63). Although it did not reach conventional statistical significance, PSA density was a good predictor of cancer grade in men with suspected disease (p = 0.06), but not under AS (p = 0.62). Conclusion: The NPV of multiparametric MRI for GS ≥ 3+4 is higher in men with suspected prostate cancer than in men under AS. PSA density ≤ 0.15 improved the prediction of intermediate to high-grade disease in patients without known cancer.

摘要
目的：对比多参数磁共振成像（multiparametric MRI）对格里森评分（Gleason score, GS）≥3+4前列腺癌的阴性预测值（negative predictive value, NPV），并评估疑似前列腺癌且接受主动监测（active surveillance, AS）的男性中此类肿瘤的预测因素。
材料与方法：本回顾性研究纳入2016年5月至2017年9月期间的76例男性受试者，其中38例为疑似前列腺癌患者，38例为接受主动监测者，所有受试者的磁共振成像均被赋予前列腺影像报告和数据系统第2版（PI-RADS v2）评分1或2分。活检结果分为无癌、GS=3+3以及GS≥3+4三类。记录受试者磁共振检查前的前列腺特异性抗原（prostate-specific antigen, PSA）水平、腺体体积及PSA密度。采用卡方检验、比例相等性检验及logistic回归对数据进行分析。
结果：疑似前列腺癌组与主动监测组中，检出中高级别前列腺癌的比例分别为12.8%（95%置信区间[95% CI]：2.3~23.3）与35.9%（95%置信区间[95% CI]：20.8~50.9），组间差异具有统计学意义（p=0.02）。GS≥3+4肿瘤的阴性预测值在疑似前列腺癌组为87.2%（95% CI：76.7~97.7），在主动监测组为64.1%（95% CI：49.0~79.2）。两组中PSA均未显著预测肿瘤分级（p分别为0.75与0.63）。尽管未达到常规统计学显著性阈值，但PSA密度可较好预测疑似前列腺癌男性的肿瘤分级（p=0.06），而在主动监测组中则无此预测价值（p=0.62）。
结论：多参数磁共振成像对GS≥3+4前列腺癌的阴性预测值，在疑似前列腺癌男性中高于接受主动监测的男性。PSA密度≤0.15可提升无已知前列腺癌患者的中高级别肿瘤预测效能。