Description: The standard prostate-specific antigen (PSA) blood test is not helpful in predicting lethal prostate cancers in men who are not treated but are placed under "watchful waiting" by their doctors, Swedish researchers say.

"Unfortunately, it turned out to be an inaccurate tool," said Dr. Katja Fall, a researcher at the Karolinska Institute in Stockholm, Sweden, and lead author of a report in the April 4 issue of the Journal of the National Cancer Institute.

But one U.S. expert, Dr. Anthony D'Amico of Harvard Medical School, Boston, said it was too soon to write off the usefulness of the PSA test for these patients, noting that the study has had far too short a follow-up to draw any solid conclusions.

Watchful waiting is a common strategy in prostate cancer, which often progresses slowly -- especially so in many older men. Because the cancer is often diagnosed in older men, one common saying in the field is that "more men die with their prosta