Study On The Value Of Diagnosis About PSA And Related Markers In Prostate Cancer With Serum PSA 4~20ng/ml Levels

Objective: To evaluate the clinical diagnostic value of serum prostate specific antigen(PSA), free PSA level(f/t-PSA), PSA density ratio(PSAD) and the(f/t-PSA)/PSA density ratio[(f/t-PSA)/PSAD] in diagnosis of prostate cancer(PCa) with serum PSA 4~10 and 10~20ng/ml levels.Methods: The clinical data of 305 patients with serum PSA 4~20ng/ml levelswho had underwent transrectal prostate ultrasound and biopsy(TPB) to obtain pathological results which are conducted as the gold standard for diagnosis were selected in the second hospital of soochow university during the period of sep 2010 to December 2014. The relationships between the various parameters(including t-PSA, f/t-PSA, PSAD and(f/t-PSA)/PSAD) and the results of prostate biopsy were studied, among them, the sensitivity, specific degrees and boundary value of each index were analyzed by receiver operator characteristic(ROC), and calculating the area under ROC curve(AUC), then determine the diagnostic value of various parameters on the PCa. All the data were analyzed on the SPSS19.0 for Windows statistical software package.Results: There were 53 men of the 305 patients(17.4%) had been diagnosed PCa, in the t-PSA level of 4~10 and 10~20ng/ml, the biopsies for PCa were 13.5%(17/126) and 20.1%(36/179) respectively, X2=2.26, there was no statistically significant difference(P>0.05). At both of the t-PSA levels, the median of age and t-PSA were no difference between PCa group and non PCa group(P>0.05), however, there were significant difference among the median of f/t-PSA, PSAD and(f/t-PSA)/PSAD(P<0.05). At the different t-PSA levels, the areas under ROC curve(AUC) of these indexes in descending order were(f/t-PSA)/PSAD, PSAD, f/t-PSA, t-PSA: the AUC of(f/t-PSA)/PSAD was statistically bigger than t-PSA, f/t-PSA; and PSAD compared with them, too(P < 0.05). Whereas there were only no significant difference between(f/t-PSA)/PSAD and PSAD. Analysis of ROC curves showed that the best cutoff value of each indicator for diagnosing PCa is: when the t-PSA levels of 4~10ng/ml, t-PSA>7.350ng/ml, f/t-PSA<0.171, PSAD>0.146ng/(ml*cm3),(f/t-PSA)/PSAD<0.812; when the t-PSA levels of 10~20ng/ml, t-PSA>13.010ng/ml, f/t-PSA<0.165, PSAD>0.216ng/(ml*cm3),(f/t-PSA)/PSAD<0.775.Results: When the t-PSA levels of 4 ~ 20ng/ml, the f/t-PSA, PSAD and(f/t-PSA)/PSAD can assist to improve the diagnostic accordance rate of PCa;(f/t-PSA)/PSAD, PSAD and f/t-PSA are useful in predicting prostate cancer in men with t-PSA levels of 4~20ng/ml,(f/t-PSA)/PSAD and PSAD are higher, the f/t-PSA is medium, are superior to t-PSA in discriminating PCa by improving test sensitivity, specificity and avoiding the unnecessary biopsies rate; When the t-PSA levels of 10~20ng/ml, if would take PSAD<0.216 for critical value(or cutoff value), it could improve the sensitivity, specificity of diagnosing PCa, and prostate biopsy positive rate.