前列腺特异抗原〈4μg／L前列腺癌经直肠超声引导穿刺活检的临床研究

The clinical study of transrectal ultrasound guided biopsies of the prostate cancer with PSA level less than 4 μg/L

目的评价经直肠超声（TRUS）引导下前列腺穿刺活检对前列腺特异抗原（PSA）〈4μg／L前列腺癌（PCA）诊断的临床价值。借以探讨提高PSA〈4μg／L的PCA诊断率的方法。方法选取59例PSA〈4μg／L怀疑PCA的患者进行TRUS引导下前列腺多点穿刺活检。分析其TRUS声像图特点尤其对前列腺内结节声像特点进行总结，并比较PCA与非PCA组患者间的PSA、前列腺特异抗原密度（PSAD）、前列腺游离抗原与总前列腺抗原比值（F／T）、前列腺体积（PV），进一步分析PSAD、F／T的各阈值范围内对PCA诊断的敏感性及持异性。结果59例受检者中经病理证实PCA16例，检出率为27％，12例PCA患者声像图检查显示前列腺结节性病变，均分布于外腺，且血流增加较良性病变及癌前病变高。PCA组与非PCA组间的PSA、PSAD、F／T、PV差异均有统计学意义，将PSAD阈值设为0．09μg／L^2时有较高的敏感性及特异性，F／T、值设为0．20时有较高的敏感性及特异性，但不及PSAD有优势。结论TRUS前列腺穿刺活检是确诊PSA〈4μg／LPCA的最有效方法之一，结合TRUS声像图特点及PSA修正方法可进一步提高PCA的检出率。

Objective To evaluate the clinical value of transrectal ultrasound（TRUS） guided biopsies of the prostate cancer（PCA） with serum prostate specific antigen（PSA） level less than 4 μg/L. Methods Fifty nine patients suspected PCA were underwent TRUS guided-biopsy. The ultrasonographic features of lesions and prostate gland were observed. The PSA, PSA density （ PSAD）, FIT （ free/total PSA ratio）, prostatic volume（PV） were compared between PCA group and non PCA group,and further analyzed the sensitivity and specificity of PSAD and F/T at different thresholds for PCA diagnosis. Results In 59 patients, 16 were proved to be cancer by pathological examination, the positive detection rate was 27 %. In these 16 patients, 12 had lesions on ultrasound, which located in outer gland. The rich vascularity was observed in PCA more than in benign and precancerous lesion. There were statistical significant differences in PSA,PSAD,F/T, PV between PCA and non PCA groups. When selecting threshold of PSAD and F/T were 0.09 and 0.20, respectively, there were the highest diagnostic specificity and sensitivity. The diagnostic specificity and sensitivity of PSAD were higher than those of F/T. Conclusions TRUS guided biopsies of the prostate is one of the most efficient methods for detection of PCA with PSA level less than 4 μg/L. Combining TRUS features with PSA parameters can further increase positive detection rate of PCA.