Department of Surgery/Urology, Cancer Hospital Barretos, Barretos, SP, Brazil.
BJU Int. 2012 Dec;110(11 Pt B):E653-7. doi: 10.1111/j.1464-410X.2012.11398.x. Epub 2012 Aug 14.
What's known on the subject? and What does the study add? In spite of its low specificity, PSA is the most widely used screening test for prostate cancer (PCa), and is considered the main cause of the stage migration recently observed. The ratio of free to total PSA (%fPSA) has been shown to increase PSA accuracy in cancer detection; however, few screening studies have systematically evaluated its role in cancer detection rates in men with PSA levels <4.0 ng/mL and normal DRE. The present study supports a possible role of %fPSA as an adjunct to screening in men with total PSA 2.5-4.0 ng/mL and normal DRE, with a marked increase in cancer detection rates in a large Brazilian PCa screening study. We believe that %fPSA maybe a useful refinement to biopsy indications in men with low PSA levels.
• To evaluate the role of the free to total prostate-specific antigen ratio (%fPSA) in identifying prostate cancer (PCa) in men with a prostate-specific antigen (PSA) level of 2.5-3.9 ng/mL and a normal digital rectal examination (DRE).
• A prospective PCa screening study was conducted, which included 17571 men aged ≥ 45 years, across six Brazilian states, where men were recalled for further evaluation in the case of either a suspicious DRE and/or PSA ≥ 4.0 ng/mL, or PSA 2.5-3.9 ng/mL and %fPSA ≤ 15. • We evaluated the impact of a %fPSA ≤ 15 on cancer detection rates and the clinical and pathological stage of tumours in men with a normal DRE and PSA 2.5-3.9 ng/mL.
• When suspicious DRE and/or PSA ≥ 4.0 ng/mL were considered as criteria to prompt further evaluation, the cancer detection rate was 3.1%. When %fPSA ≤ 15 in men with total PSA levels of 2.5-3.9 ng/mL were considered as criteria, the PCa detection rate increased to 3.7%. Considering %fPSA ≤ 15 in men with PSA 2.5-3.9 ng/mL and normal DRE, the positive predictive value of biopsy was 31.1%. • Clinical stage was more favourable among men with PSA 2.5-3.9 ng/mL, normal DRE, and %fPSA ≤ 15 compared with men with normal DRE and PSA ≥ 4.0 ng/mL (P= 0.02). • Among those who underwent radical prostatectomy, pathological stage and the proportion of insignificant tumours were similar between men with PSA 2.5-3.9 ng/mL, normal DRE findings and %fPSA ≤ 15, and men with PSA ≥ 4.0 ng/mL.
• The use of %fPSA ≤ 15 as a biopsy indication in men with normal DRE and PSA 2.5-4.0 ng/mL in a PCa screening programme, increased cancer detection rates. Tumours in this subset of patients had similar pathological characteristics. • Using %fPSA ≤ 15 to indicate biopsy in men with PSA 2.5-3.9 ng/mL is a useful adjunct to PCa screening.
尽管 PSA 的特异性较低，但它仍是目前应用最广泛的前列腺癌（PCa）筛查试验，并且被认为是最近观察到的分期迁移的主要原因。游离前列腺特异性抗原（fPSA）与总前列腺特异性抗原（tPSA）的比值（%fPSA）已被证明可提高癌症检测的 PSA 准确性；然而，很少有筛查研究系统地评估了其在 PSA<4.0ng/mL 和正常直肠指诊（DRE）的男性中对癌症检测率的作用。本研究支持 %fPSA 可能在 PSA 水平为 2.5-4.0ng/mL 和正常 DRE 的男性中作为筛查辅助手段的作用，在一项大型巴西 PCa 筛查研究中，癌症检测率显著增加。我们认为 %fPSA 可能是对 PSA 水平较低的男性进行活检指征的有用改进。
评估游离前列腺特异性抗原（fPSA）与总前列腺特异性抗原（tPSA）的比值（%fPSA）在 PSA 水平为 2.5-3.9ng/mL 和正常 DRE 的男性中识别前列腺癌（PCa）的作用。
一项前瞻性 PCa 筛查研究纳入了 17571 名年龄≥45 岁的男性，来自巴西的六个州，在 DRE 可疑和/或 PSA≥4.0ng/mL 或 PSA 2.5-3.9ng/mL 和 %fPSA≤15 的情况下，对这些男性进行进一步评估。我们评估了在 DRE 正常和 PSA 2.5-3.9ng/mL 的男性中，%fPSA≤15 对癌症检测率和肿瘤临床及病理分期的影响。
当可疑 DRE 和/或 PSA≥4.0ng/mL 被视为进一步评估的标准时，癌症检测率为 3.1%。当 PSA 2.5-3.9ng/mL 的男性 %fPSA≤15 时，PCa 的检测率增加到 3.7%。当 PSA 2.5-3.9ng/mL 和 DRE 正常的男性 %fPSA≤15 时，活检的阳性预测值为 31.1%。与 DRE 正常和 PSA≥4.0ng/mL 的男性相比，PSA 2.5-3.9ng/mL、DRE 正常和 %fPSA≤15 的男性的临床分期更有利（P=0.02）。在接受根治性前列腺切除术的患者中，PSA 2.5-3.9ng/mL、DRE 正常和 %fPSA≤15 的患者与 PSA≥4.0ng/mL 的患者的病理分期和无意义肿瘤的比例相似。
在 PCa 筛查计划中，将 %fPSA≤15 用作 DRE 正常和 PSA 2.5-4.0ng/mL 的男性的活检指征，可提高癌症检测率。这些亚组患者的肿瘤具有相似的病理特征。在 PSA 2.5-3.9ng/mL 的男性中使用 %fPSA≤15 来指示活检是 PCa 筛查的有用辅助手段。
