PSAD、F／T在tPSA低水平异常的前列腺癌诊断价值

目的：比较前列腺特异性抗原密度（PSAD）、游离PSA （fPSA）与总PSA （tPSA）比值（F/T）在tPSA 4～10、10～20μg/L水平的前列腺癌诊断价值。方法选取tPSA 4～20μg/L、经直肠B超前列腺穿刺活组织检查（活检）的449例患者，对PSAD、F/T和前列腺活检结果的关系进行研究。结果449例中前列腺癌78例（17.4％），tPSA 4～10、10～20μg/L 阳性率分别为10.4％、23.1％（P＜0.001），F/T和PSAD在穿刺前列腺癌组和非前列腺癌组间比较差异均有统计学意义（P＜0.01），受试者工作特征曲线下面积（AUC） PSAD＞F/T＞tPSA，PSAD与tPSA间AUC比较差异有统计学意义（P＜0.01），F/T和tPSA间AUC比较差异无统计学意义。当诊断敏感度为100％时，在PSA 4～10、10～20μg/L水平，PSAD特异度分别为5.0％和2.1％，可分别避免不必要前列腺穿刺4.9％和2.4％。结论在PSA 4～20μg/L水平上，PSAD和F/T对预测是否行前列腺穿刺有帮助，在诊断敏感度和特异度上，PSAD优于F/T。

Utility of PSA density and free PSA percentage in diagnosis of prostate cancer with low abnormal PSA levels

Objective To evaluate PSA density （PSAD）and free PSA percentage （F/T）in diagno-sis of prostate cancer （PCa）with serum PSA 4~1 0 and 1 0~20 μg/L levels. Methods Four hundred and forty-nine men with the PSA levels 4~20 μg/L who underwent transrectal prostate ultrasound and biopsy were selected. The relationships between the result of prostate biopsy and PSAD,F/T were studied. Results Sev-enty-eight of the 449 men （1 7.4%）had been diagnosed PCa. In the PSA level of 4~1 0 and 1 0~20 μg/L, the biopsies for PCa were 1 0.4%and 23.1%,respectively （P＆lt;0.01 ）. At both of the PSA levels,the medi-an of PSAD and F/T were significantly different between PCa group and non-PCa group （P＆lt;0.01 ）. The areas under ROC curve （AUC）of these indexes in descending order were PSAD,F/T,tPSA. The AUC of PSAD was statistically bigger than F/T and tPSA,whereas there was no significant difference between F/T and tPSA.Diagnostic test showed that when test sensitivity was 1 00%,within the range of serum PSA of 4~1 0 and 1 0~20 μg/L,the specificity of PSAD was 5.0%and 2.1%,respectively. PSAD could avoid unnecessary biopsies 4.9% and 2.4%,respectively. Conclusions This result suggested that PSAD and F/T are useful in predic-ting prostate cancer in men with PSA levels of 4~20 μg/L. PSAD is superior to F/T in discriminating PCa by improving test sensitivity and specificity.