Prostate Cancer: PSA Change May Be Key to Risk
Researchers Say Tracking PSA Changes Indicates Who's at Risk of Dying When Cancer Returns
Zeroing In on Prostate Cancer Death Risk
Many men elect to have their prostate glands removed when they are diagnosed
with prostate cancer. With no prostate, their PSA levels should drop to zero.
But within 10 years of surgery, more than a third of these men eventually have
PSA appear in their blood.
Where does the PSA come from? Prostate cancer cells that have begun to grow
again. But that's not always bad news. These recurrent cancers often grow very
"The nice thing is that a PSA test can identify cancer recurrence years
before we would detect it clinically," Freedland says. "But then, it is
hard to figure out who has aggressive cancer and who doesn't."
After looking at hundreds of cases, Freedland's team came up with three
things that predict which men are likely to have problems:
- How quickly the PSA became detectable after surgery. Men whose PSA came
back more than three years after surgery did better than those whose PSA came
back in three years or less.
- The most important factor, however, is how fast the PSA goes up. This is
the doubling time -- how long it took for a PSA of 1 to become 2, and 4, and 8,
and so on.
- The Gleason score of the original tumor. Gleason score is based on what a
cancer looks like under the microscope. The higher the score, the more
aggressive looking the cancer. Men with Gleason scores of less than 8 did
better than those with Gleason scores of 8 or more.
"When you put it all together, we are 84% accurate in predicting
long-term outcome for these men," Freedland says.
For example, the very worst prediction would be a man whose PSA reappeared
in less than three years, whose PSA level doubled in less than three months,
and who had a Gleason score of more than 8. Such men have a 51% chance of
surviving for five years, a 1% chance of surviving for 10 years, and less than
a 1% chance of surviving for 15 years.
The best prediction would be for a man whose PSA reappeared after more than
three years, whose PSA level took at least 15 months to double, and whose
Gleason score was less than 8. Such men have a 100% chance of surviving for
five years, a 98% chance of surviving for 10 years, and a 94% chance of
surviving for 15 years.
"The significance of the finding is it can help us identify who needs
treatment after surgery recurrence and who doesn't," Freedland says.
Great Information -- but What Can a Man Do About It?
Knowing who is at risk is helpful. But what's missing is knowing exactly
what to do about it, says Mitchell S. Anscher, MD, professor of radiation
oncology at Duke University Medical Center. Anscher's editorial accompanies the
D'Amico and Freedland studies.