Empiric antibiotics for an elevated prostate-specific antigen (PSA) level: a randomised, prospective, controlled multi-institutional trial

Objective To determine the impact of empiric antibiotics on men with an elevated prostate-specific antigen (PSA) level. Subjects/Patients and Methods Men of any age with a PSA level of >2.5ng/mL and normal digital rectal examination undergoing their first prostate biopsy were recruited from five medical centres. Patients with previous biopsy, prostate cancer, urinary tract infection (UTI) or prostatitis within the prior year, antibiotic use within 1 month, 5-reductase inhibitor use, allergy to fluoroquinolones or clinical suspicion of UTI were excluded. Men were randomised to 2 weeks of ciprofloxacin or no antibiotic. A PSA measurement was obtained 21-45 days after randomisation immediately before prostate biopsy. The primary endpoint was the change in PSA level between baseline and immediately before biopsy. Results Complete data were available for 77 men with a mean (interquartile range) age of 60.6 (53-66) years. In the control group of men not receiving antibiotic (39 men), the mean baseline and pre-biopsy PSA levels were 6.5 and 6.9ng/mL, respectively (P = 0.8). In men receiving ciprofloxacin (38 men), the mean baseline PSA level was 7.6ng/mL and after 2 weeks of ciprofloxacin was 8.5ng/mL (P = 0.7). Compared with controls not receiving antibiotic, use of ciprofloxacin was not associated with a statistically significant change in PSA level (P = 0.33). Prostate cancer was detected in 36 (47%) men, 23 (59%) in the control group and 13 (34%) in the antibiotic group (P = 0.04). Detection rates were not significantly associated with the change in PSA level between baseline and biopsy. The primary limitation of the study is early stoppage due to an interim futility analysis and poor accrual. Conclusion Despite not meeting the target accrual goal, empiric use of antibiotics for asymptomatic men with an elevated PSA level does not appear to be of clinical benefit.