MedWire News: Although serum total prostate-specific antigen (PSA) levels are decreased by antibiotic therapy, the risk for prostate cancer is not reduced, warn Turkish investigators.
Some urologists prescribe antibiotics before biopsy for men with newly increased PSA levels without performing expressed prostatic secretion in the belief that the patients have subclinical infectious prostatitis. However, the practice remains controversial.
To determine the impact of antibiotics on serum total, free, and percent free PSA, as well as on PSA density and prostate cancer incidence, Evren Süer, from the University of Ankara, and colleagues studied 100 men with total PSA levels between 4 ng/ml and 10 ng/ml. None of the patients had an abnormal digital rectal examination.
The participants were given ofloxcacin 400 mg daily for 20 days and re-evaluated, and transrectal ultrasound-guided prostate biopsy was performed, regardless of the total PSA value.
The average age of the patients was 62.9 years. Average total PSA before and after treatment was 6.05 ng/ml and 5.55 ng/ml, respectively. On biopsy, 23% of patients had histologically proven prostate cancer. There were no significant differences between men with and without prostate cancer in age, pretreatment PSA, free PSA, percent free PSA, and PSA density.
Average total PSA, free PSA, and PSA density decreased after treatment in men with and without prostate cancer. But the reductions in total PSA and PSA density were not significant in prostate cancer patients and the reduction in free PSA in cancer-free patients was not significant.
In addition, percent free PSA increased nonsignificantly in patients without prostate cancer and decreased significantly in prostate cancer patients after treatment. There was a significant difference in the change in percent free PSA between patients with and without prostate cancer.
Of the 17 men with post-treatment PSA levels <4 ng/ml, 29.4% had prostate cancer on biopsy. There were no differences between free PSA, percent free PSA, and PSA density for differentiating patients with and without prostate cancer in this group.
The team concludes in the Journal of Urology: “Prescribing antibiotics for asymptomatic men with a newly increased PSA may not be an appropriate way of management.”
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