Arai Y, Maeda H, Ishitoya S, Okubo K, Okada T, Aoki Y
Department of Urology, Kurashiki Central Hospital, Japan.
J Urol. 1997 Sep;158(3 Pt 1):861-4. doi: 10.1097/00005392-199709000-00046.
To improve the specificity of cancer detection in patients with normal digital rectal examination and intermediate prostate specific antigen (PSA) level, PSA density has been recommended, with biopsy based on a PSA density of 0.15 or more. PSA density is reportedly higher in Japanese men than in white men, because of physiological differences between the 2 races. We prospectively evaluated PSA density as a discriminator of prostate cancer in Japanese men.
We evaluated prospectively 60 consecutive men with normal digital rectal examinations and serum PSA levels of 4.1 to 10.0 ng./ml. enrolled during a 17-month period. All patients underwent transrectal ultrasound guided sextant biopsies, regardless of calculated PSA density and transrectal ultrasound findings. Serum PSA levels were determined by IMx assay.
Overall, 8 of 60 men (13%) had prostate cancer. There was no significant difference in mean PSA between those with positive and those with negative biopsies, but the difference was significant in the mean PSA density (mean 0.24 and 0.15, respectively, p < 0.01). Receiver operating characteristics curves for PSA and PSA density demonstrated superior benefit for PSA density in this patient population. A reference PSA density value of 0.19 was chosen because it showed the highest sum of sensitivity and specificity, which gave a sensitivity of 75%, a specificity of 87%, a positive predictive value of 46% and a negative predictive value of 96%.
The results suggest that PSA density improves the specificity of cancer detection in men with a normal digital rectal examination and an intermediate PSA level. Although further study with a larger patient population is needed to obtain a best-fit value, an optimal PSA density cutoff seems to be higher than that recommended in the literature from western countries. Because of possible racial differences in serum PSA and prostate volume, the role of PSA density in Asian men should be studied independently.
为提高直肠指检正常且前列腺特异性抗原（PSA）水平处于中等范围的患者癌症检测的特异性，推荐使用PSA密度，并基于PSA密度0.15及以上进行活检。据报道，由于两个种族的生理差异，日本男性的PSA密度高于白人男性。我们前瞻性地评估了PSA密度作为日本男性前列腺癌鉴别指标的价值。
我们前瞻性地评估了连续60名直肠指检正常且血清PSA水平为4.1至10.0 ng/ml的男性，这些患者在17个月期间入组。所有患者均接受经直肠超声引导的六分区活检，无论计算出的PSA密度及经直肠超声检查结果如何。血清PSA水平通过IMx测定法测定。
总体而言，60名男性中有8名（13%）患有前列腺癌。活检阳性和阴性患者的平均PSA无显著差异，但平均PSA密度差异显著（分别为0.24和0.15，p<0.01）。PSA和PSA密度的受试者工作特征曲线表明，在该患者群体中PSA密度具有更大优势。选择0.19作为参考PSA密度值，因为它显示出最高的敏感性和特异性之和，敏感性为75%，特异性为87%，阳性预测值为46%，阴性预测值为96%。
结果表明，PSA密度提高了直肠指检正常且PSA水平中等的男性癌症检测的特异性。尽管需要对更大的患者群体进行进一步研究以获得最佳拟合值，但最佳PSA密度临界值似乎高于西方国家文献中推荐的值。由于血清PSA和前列腺体积可能存在种族差异，应独立研究PSA密度在亚洲男性中的作用。
