Diagnosis of cancer of the prostate by determining the blood levels of specific prostatic antigen, rectal examination, and transrectal echography

The usefulness of Prostate Specific Antigen (PSA), tactile rectal examination (TRE) and transrectal ultrasound (TRU) for the diagnosis of prostate cancer (PCa) was studied in 114 patients who came in for an evaluation of their mictional symptoms. Patients underwent random ultrasound-guided transrectal biopsies following findings of abnormal TRE and/or serum PSA concentrations > 5 ng/ml.

Of the total series, 71% presented TRE abnormalities and 52% presented hypoechoic areas in the TRU (only ones to be considered suspicious). Also, 26%, 23% and 51% of patients presented normal (0-5 ng/ml), intermediate (5-10 ng/ml), and high (> 10 ng/ml) concentrations of serum PSA. Incidence of PCa was 31%. Based on the individual tests, both positive and negative predictive values were higher for serum PSA concentrations > 10 ng/ml. By combining the tests results, the diagnosis percentage was also higher with PSA levels > 10 ng/ml. Positive predictive value was 81% in patients with all three tests positive, 73% with suspicious TRE and high PSA and 70% with suspicious TRU and high PSA.

Our results corroborate the superiority and efficacy of random biopsies over selective biopsies of hyperechoic areas. Nevertheless, of 21 patients with negative prostate biopsies who underwent TUR or retropubical adenomectomy, 28% had PCa. These findings indicate that random biopsies are associated with a percentage of false negatives which varies depending on the features of the sample being studied.

In conclusion, PSA is the ideal complement to TRE, and the association of these two tests constitutes the best indication for an ultrasound-guided random prostate biopsy, with independence of any TRU findings.

CITATION  Actas Urol Esp. 1993 Jun;17(6):341-5; discussion 345-6