Manohar P Ram, Rather Tanveer Ahmed, Khan Shoukat H
Department of Nuclear Medicine, SKIMS, Srinagar, Jammu and Kashmir, India.
World J Nucl Med. 2020 Jul 1;19(3):255-259. doi: 10.4103/wjnm.WJNM_77_19. eCollection 2020 Jul-Sep.
Radionuclide whole-body bone scan is a useful investigation of choice to detect the skeletal metastases in prostate cancer. It is indicated in patients having elevated serum prostate-specific antigen (Sr. PSA) or patients with bone pain. Elevated Sr. PSA levels have high predictive value for skeletal metastases; however, there is no consensus regarding cut-off value of Sr. PSA above which bone scan is indicated. This study was performed to find out the accuracy of Sr. PSA test and to know the optimal cut-off value of Sr. PSA with high sensitivity and specificity in the prediction of skeletal metastases on bone scan in prostate cancer patients. A retrospective analysis of medical records of 307 prostate cancer patients referred to the department of nuclear medicine for bone scan between June 2009 and June 2014 was done. Of 307 patients, 15 cases were excluded due to nonavailability of Sr. PSA. Bone scan was performed 3 h after administration of 20 mCi Tc-99m methylene diphosphonate intravenously. Whole-body sweep imaging was performed and spot views were taken wherever required. Of 292 cases, 174 (59.58%) patients had positive bone scan for metastases and 118 (40.41%) patients had negative bone scan for metastases. Maximum and minimum Sr. PSA levels in positive and negative bone scan patients were 1260 and 0.02 ng/ml and 198.34 ng/ml and 0.01 ng/ml, respectively. On comparison of the mean Sr. PSA levels between positive and negative groups, we found significant Sr. PSA levels ( < 0.05). We used receiver operating characteristic (ROC) curve analyses to find out the accuracy of Sr. PSA test and to know the optimal cut-off value of Sr. PSA with maximum sensitivity and specificity in the prediction of skeletal metastases on bone scan. Area under ROC curve was 0.878 (87%). This indicates that the accuracy of Sr. PSA test in the prediction of skeletal metastases on bone scan was good. The optimal cut-off value of Sr. PSA in the prediction of positive bone scan for skeletal metastases in the management of prostate cancer was 29.16 ng/ml, with sensitivity and specificity of 89.0% and 74.6%, respectively. In this study, we conclude that the accuracy of Sr. PSA test in the prediction of skeletal metastases is good. ROC-derived optimal cut-off value of Sr. PSA for positive skeletal metastases on bone scan is >29.16 ng/ml; thus, the chances of getting positive bone scan for skeletal metastasis are less in prostate cancer patients with Sr. PSA <29.16 ng/ml. ROC-derived sensitivity and specificity of different possible cut-off points of Sr. PSA help reduce the false positive results and increase the diagnostic accuracy of bone scan in the detection of skeletal metastases in prostate cancer patients.
放射性核素全身骨扫描是检测前列腺癌骨转移的一种常用且有效的检查方法。适用于血清前列腺特异性抗原（Sr. PSA）升高的患者或有骨痛的患者。Sr. PSA水平升高对骨转移具有较高的预测价值；然而，对于提示需要进行骨扫描的Sr. PSA临界值尚无共识。本研究旨在探讨Sr. PSA检测的准确性，并确定在预测前列腺癌患者骨扫描骨转移方面具有高敏感性和特异性的Sr. PSA最佳临界值。对2009年6月至2014年6月间转诊至核医学科进行骨扫描的307例前列腺癌患者的病历进行回顾性分析。307例患者中，15例因无法获取Sr. PSA数据而被排除。静脉注射20 mCi Tc-99m亚甲基二膦酸盐后3小时进行骨扫描。进行全身扫描成像，并在需要的部位拍摄局部图像。292例患者中，174例（59.58%）骨扫描显示转移阳性，118例（40.41%）骨扫描显示转移阴性。骨扫描阳性和阴性患者的Sr. PSA最高和最低水平分别为1260和0.02 ng/ml以及198.34和0.01 ng/ml。比较阳性和阴性组的平均Sr. PSA水平，发现差异有统计学意义（<0.05）。我们采用受试者操作特征（ROC）曲线分析来确定Sr. PSA检测的准确性，并了解在预测骨扫描骨转移方面具有最大敏感性和特异性的Sr. PSA最佳临界值。ROC曲线下面积为0.878（87%）。这表明Sr. PSA检测在预测骨扫描骨转移方面准确性良好。在前列腺癌管理中，预测骨扫描骨转移阳性的Sr. PSA最佳临界值为29.16 ng/ml，敏感性和特异性分别为89.0%和74.6%。在本研究中，我们得出结论，Sr. PSA检测在预测骨转移方面准确性良好。ROC得出的骨扫描骨转移阳性的Sr. PSA最佳临界值>29.16 ng/ml；因此，Sr. PSA<29.16 ng/ml的前列腺癌患者骨扫描显示骨转移阳性的可能性较小。ROC得出的Sr. PSA不同可能临界值的敏感性和特异性有助于减少假阳性结果，提高骨扫描在检测前列腺癌患者骨转移中的诊断准确性。
