Serum PSA and percent free PSA value changes after antibiotic treatment. A diagnostic method in prostate cancer suspects with asymptomatic prostatitis.

INTRODUCTION

An association between inflammatory foci in prostatic tissues and elevated serum prostate-specific antigen (PSA) levels has been a controversial issue. We studied the effects of antibiotics on elevated PSA levels to improve the diagnostic value of prostate cancer findings.

PATIENTS AND

METHODS

Of 65 asymptomatic men with inconstant PSA elevation, 51 with laboratory signs of prostatitis received antibiotics instead of undergoing a prompt prostate biopsy. Asymptomatic prostatic inflammation was defined as the presence of >10 white blood cells/high-power field in the post-prostate massage urine. Follow-up measurements of PSA and percent free PSA values were obtained.

RESULTS

Approximately 30% of the patients had a treatment response, defined as PSA decrease >20% from baseline. The range of the variations of PSA and percent free PSA values, expressed as coefficient of variation, also decreased significantly. Moreover, antibiotic treatment lowered the extent of histological prostatic inflammation in some patients.

CONCLUSIONS

Subclinical prostatic inflammation potentially contributes to an elevated PSA level and its variation among prostate cancer suspects. Watchful observation may be an optional tool for patients showing a significant PSA decrease following antibiotic treatment.