Rectal Cleansing Before Prostate Biopsy May Not Reduce Infections

By Will Boggs, MD

NEW YORK (Reuters Health) Oct 09 - Rectal cleansing before prostate biopsy may not reduce the risk of infectious complications, researchers say.

"Infectious complications after prostate biopsy are a highly relevant clinical issue and we need to find ways to reduce the risk," Dr. Peter C. Black from University of British Columbia in Vancouver, Canada told Reuters Health. "A lot of urologists are changing the antibiotics that they give and are undertaking measures that appear to make sense clinically, but we should base these decisions on clinical trials as best we can, and so we need to continue to do these types of trials."

In this case, Dr. Black and colleagues investigated whether povidone-iodine cleansing of the anterior rectum prior to transrectal ultrasound guided prostate biopsy would decrease the rate of infectious complications.

The randomized trial, reported online October 3 in The Journal of Urology, included 865 men (421 in the treatment group, 444 in the control group).

There were only 11 infectious complications (2.6%) in the treatment group and 20 (4.5%) in the control group, for a relative risk reduction of 42% (p=0.15).

"The trial was negative, so we cannot say with any conviction that povidone-iodine works as we administered it," Dr. Black said. "However, I do believe that we would have had a good chance to demonstrate a statistically significant difference between the groups if we had a larger study. We saw approximately half the number of events than we expected, so our study ended up being under-powered."

Nearly half the men (48%) with infectious complications (including eight of the 11 with sepsis) had ciprofloxacin-resistant gram-negative bacteria in the rectal culture, compared with only 19.5% of the total study population.

It is common to give an antibiotic to a patient with an elevated prostate specific antigen level to see if it will go down, Dr. Black said. "We know that this does not affect the subsequent risk of being diagnosed with prostate cancer," he added. "This practice will, however, increase the risk of infectious complications after biopsy and should be avoided. If a patient has been on a fluoroquinolone within three months, it may be best to delay the biopsy if it does not appear to be clinically urgent."

The researchers say there were only minimal adverse reactions to povidone-iodine, with four patients reporting anal itching.

"It is so easy to perform the cleansing - and so well tolerated by the patients - that it is tempting to adopt it as a routine practice, but we have not done this," Dr. Black concluded. "We are currently in the process of drawing up new recommendations for Vancouver General Hospital for all patients undergoing biopsy."