SAN FRANCISCO—New findings presented here at the annual Genitourinary Cancers Symposium challenge the widespread practice of placing patients on an empiric course of antibiotics for a newly elevated PSA level.

Scott E. Eggener, MD, of the University of Chicago, and colleagues studied 77 men with a newly elevated PSA level. Of these, 38 were randomized to receive ciprofloxacin 500 mg twice daily for two weeks or no antibiotic (control group). PSA was measured 21-45 days following randomization and immediately prior to prostate biopsy.

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Prostate biopsy revealed prostate cancer in 36 men (47%). Detections rates did not differ significantly between patients with an increasing PSA or decreasing PSA between the two measurements, said Michael Christopher Large, MD, a urologic oncology fellow at the University of Chicago, who presented study findings. Mean PSA levels at randomization into the study were 7.6 ng/mL in the antibiotic group and 6.5 ng/mL in the control arm. The mean PSA levels at biopsy were 8.5 and 6.9 ng/mL, respectively.

In the antibiotic group, cancer was found after a PSA increase in seven (44%) of 16 patients after a PSA decrease in five (24%) of 21 patients. In the control arm, cancer was found after a PSA increase in 12 (60%) of 20 patients and after a PSA decrease in 11 (58%) of 19 patients.

“Prescription of empiric antibiotics in asymptomatic men with elevated PSA is not of any clinical benefit,” Dr. Large said.

The symposium is co-sponsored by the American Society of Clinical Oncology, the American Society of Radiation Oncology, and the Society of Urologic Oncology.