Major Finding: Asymptomatic patients with elevated PSAs who were given 6 weeks of ciprofloxacin saw mean PSA levels decline 11%, compared with an increase of 4% in patients in a control group. The difference was not statistically significant.
Data Source: Randomized controlled trial of 120 men.
Disclosures: The investigators stated that they had no conflicts and that the study received no specific funding.
SAN FRANCISCO — Some physicians prescribe antibiotics to men with elevated prostate specific antigen to differentiate those who have infection or inflammation from those who have cancer, but a randomized controlled trial shows no significant change in mean PSA levels between 60 asymptomatic men given a 6-week regimen of a fluoroquinolone and another 60 men assigned to observation.
Those who took 500 mg of ciprofloxacin twice daily for 6 weeks experienced an 11% decline in mean PSA values, compared with a 4% increase in PSA values among men in the observation group.
The difference was neither statistically nor clinically significant, Dr. Robin R. Bhavsar reported.
Thirty patients in the ciprofloxacin arm and 26 patients in the observation arm ended up having biopsies. The cancer detection rate was 53% in the ciprofloxacin arm and 42% in the observation arm, a difference with no statistical significance, said Dr. Bhavsar of the Medical University of South Carolina, Charleston.
The investigation included asymptomatic men with PSAs between 4.0 and 20.0 ng/mL. Patients were excluded if they had used 5-alpha-reductase inhibitors, if they had undergone prior prostate surgery, had a prior diagnosis of prostate cancer, had used androgen ablative therapies, had evidence of prostatitis, or if they were allergic to fluoroquinolones.
“There's a natural PSA variation in men, and the PSA may increase or decrease spontaneously with or without the use of antibiotics,” Dr. Bhavsar said.
Some physicians may argue that it still makes sense to use antibiotics in these men because of the small risk of adverse events, but Dr. Bhavsar noted that unnecessary antibiotics add cost and may lead to the development of resistant organisms. In addition, there are rare adverse events, such tendon rupture, associated with long-term antibiotic use.
Dr. Bhavsar said that none of the men in either of his groups experienced dramatic decreases in PSA levels.