Each year, more than a million American men have a prostate biopsy, an invasive procedure to discover whether the prostate gland is cancerous. While most prostate biopsies turn out to be negative, recent studies show, the rate of cancer detection as a result of biopsies ranges from 17 to 44 percent. But an alarming number of the men who undergo the procedure are also getting infections that are resistant to antibiotics. The problem is so serious that Consumer Reports’ medical consultants say men should be cautious about prostate cancer screening.

A biopsy is the usual follow-up procedure if a man’s prostate-specific antigen (PSA) level is consistently elevated, as shown by a blood test. In a standard biopsy, a urologist uses an ultrasound probe to guide a needle through the wall of the rectum and into the prostate gland, taking multiple tissue samples to examine for cancerous cells. Since the rectum is full of bacteria, doctors should prescribe antibiotics before and after the procedure to thwart infection.

The latest research suggests that between 1 and 4 percent of men who have a prostate biopsy will develop an infection requiring hospital care. The portion of men who needed to be hospitalized for an infection within 30 days of having a prostate biopsy increased from 0.6 percent in 1996 to 3.6 percent in 2005, according to a study of 75,190 Canadian men published in the Journal of Urology. A U.S. study of 17,472 men enrolled in Medicare covering a 16-year span found an increased rate of infections requiring hospitalization. The bump was seen toward the end of the study.

In the last decade, some bacterial strains have become resistant to the class of antibiotics that were once highly effective: fluoroquinolones such as ciprofloxacin (Cipro and generic). Studies suggest that about one in five men undergoing biopsies harbor E. coli bacteria that are resistant to fluoroquinolones. They are more likely to develop infections of the urinary tract or bloodstream and land in a hospital’s intensive care unit.

With proper precautions, prostate biopsies can be done with a lower risk of infection. It’s worth noting that complications unrelated to infections have become less common, so the overall rate of hospitalizations after biopsies decreased from 12 percent in the early 1990s to about 5 percent by 2007, according to that Medicare study. So don’t let a fear of infection deter you from having a prostate biopsy if you and your doctor decide it’s appropriate.

“The best way to reduce a biopsy complication is to reduce unnecessary biopsies,” says Edward Schaeffer, an associate professor at the Johns Hopkins University School of Medicine. Considering all the evidence, here’s what Consumer Reports’ medical experts advise:

Consider skipping prostate-cancer screening altogether. It can detect prostate cancer early, but testing 1,000 men every one to four years from age 55 to 69 has been shown to prevent only up to one death from the disease. Also, PSA testing can lead to unneeded biopsies. Consumer Reports says men age 50 to 74 should talk with a doctor to see whether the benefits of the test outweigh the risks based on several factors. Older men rarely need the PSA test because the cancer typically progresses so slowly that treatment doesn’t improve survival. Because the cancer is uncommon before age 50, younger men should consider testing only if they’re at high risk. (Risk factors include a family history of the disease, being African American and smoking.)

Don’t assume that you need a biopsy if your PSA is elevated. Other causes for high PSA levels may include an enlarged prostate, recent sexual intercourse, prostatitis and even long bicycle rides. It’s often reasonable to wait and repeat the PSA blood test. Discuss with your doctor whether the potential benefit of a biopsy outweighs the harm.

If you decide to have a biopsy, ask your urologist to first do a rectal swab to determine if you are harboring antibiotic-resistant bacteria. It should be done about a week before the biopsy so that results can guide the choice of antibiotics, reserving broad-spectrum antibiotics for when they are needed. Insurance usually covers the test.

A transperineal biopsy, which avoids the bacteria-laden rectum by inserting a needle through the perineum (the space between the anus and the scrotum), is another available option, but it’s not often used to reduce the risk of infection. That procedure is more typically used in rare cases where, for instance, a traditional rectal biopsy isn’t possible.

Copyright 2013. Consumers Union of United States Inc.

For further guidance, go to www.ConsumerReports.org/Health, where more detailed information, including CR’s ratings of prescription drugs, treatments, hospitals and healthy-living products, is available to subscribers.