The PSA blood test is still being done on men over age 75 despite recommendations against its use for prostate screening, a U.S. review finds. 

According to one interpretation of Wednesday's research into the U.S. Preventive Services Task Force recommendations,n American business magnate Warren Buffett, 81, should never have been given a PSA test. The panel offers guidance on when prostate cancer screening should be avoided or done for various age groups.

Buffett's announcement of his diagnosis last week has renewed debate on the accuracy and value of PSA screening.

In many men Buffett's age, the prostate-specific antigen test has no benefits and could be harmful.

The men's tumours are likely to be slow growing, and they're likely to die of something else before the cancer causes damage.

Writing in the Journal of the American Medical Association, Dr. Scott Eggener of the surgery department at the University of Chicago and his co-authors said the PSA screening rate for this age group increased slightly to nearly 44 per cent in 2010, two years after the recommendations were released.

Selective screening "is reasonable to consider for the healthiest men over 75," Eggener said.

Men in their 40s are more likely to benefit from early diagnosis and prostate treatment, the authors of the letter said.

Draft recommendations from the task force are more critical of PSA for men at any age, a subject that is still under debate.

The findings suggest patients and oncologists did not adjust their behaviour after the last guidelines came out. There are lingering questions about overtreatment of prostate cancer, which can cause impotence, incontinence and other problems.

Urologists say the Canadian approach is to do the PSA test and biopsy, and then watch men who show features that suggest they don't need to be treated.

The American Cancer Society and the American Urological Association discourage screening for men whose life expectancy is 10 years or less, but suggest that a man who is expected to live 10 years or longer should talk about the risks and benefits of the screening with his doctor.

The research was based on data from annual in-person interviews in the U.S. The self-reported data is likely an underestimate of how many men actually get PSA screening, the researchers said.

The U.S. Department of Defence and the University of Chicago Medicine funded the research.