Three-way measurement improves prediction of prostate cancer return
24 July 2009
Cancer experts at Johns Hopkins University in the US have shown that
a three-way combination of measurements has the best chance yet of
predicting prostate disease metastasis.
The new prediction method comprises the length of time it takes for
PSA (prostate-specific antigen) to double, Gleason score (a numeric
indicator of prostate cancer aggressiveness as seen under the
microscope), and the interval between surgical removal of the prostate
and the first detectable PSA level.
According to Johns Hopkins investigators, combining these three
measurements more accurately estimates risk that the cancer has spread
than do other methods and should help determine which patients may
benefit from additional therapy when PSA levels rise after surgery to
remove the prostate.
Findings from the study presented at the June 2009 annual meeting of
the American Society of Clinical Oncology (ASCO) may also help resolve
the debate on when and in what form secondary treatments should occur.
“There is much debate on whether to prescribe immediate treatment for
a man whose PSA begins to rise after he has had prostate cancer surgery,
or to delay it,” says Emmanuel Antonarakis, M.D., Johns Hopkins Kimmel
Cancer Center investigator. “Studies suggest that most men live the same
length of time overall whether they receive therapy at the first sign of
a rising PSA or wait until the cancer has spread to other sites.”
After reviewing the records of 774 men whose PSA rose after surgery
to remove the prostate, the researchers found that Gleason score and two
measurements for PSA were the strongest risk factors for prostate cancer
Men with Gleason scores in the highest range, between eight and 10,
were twice as likely to develop metastatic cancer. In men whose PSA
became detectable within three years after surgery, cancer was more than
three times more likely to spread to other organs. Finally, men whose
PSA doubled the fastest, within three months, were more than 20 times
more likely to develop metastatic cancer than men whose PSA look longer
than 15 months to double.
For men enrolled in the study, it took a median of 10 years for the
disease to reappear on imaging scans. “The 10-year average will not
apply to every man, so we wanted to know what factors put men at higher
risk for their cancer progressing earlier,” says Mario Eisenberger,
M.D., professor of oncology at the Johns Hopkins Kimmel Cancer Center.
An increase in PSA, or prostate specific antigen, occurs in
approximately 20 percent to 30 percent of men after surgery to remove
the cancerous prostate, says Antonarakis. In these patients, the newly
emerging prostate cancer cells are rarely detectable on imaging scans.
When faced with the likelihood that their cancer has spread, many men
opt to undergo hormone therapy, which blocks testosterone production, a
fuel for prostate cancer. The side effects, which mimic those of
menopausal women, include hot flashes, night sweats, osteoporosis,
metabolic syndrome and coronary disease, and can be debilitating, says
Besides immediate hormone therapy, other options for men whose PSA is
rising are to use hormone therapy intermittently, enroll in clinical
trials testing experimental therapies or combinations of them, or to
“watch and wait” until imaging scans can locate metastatic disease.
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