Sun 19 Mar 2006 09:43 AM CST


A consortium of prostate cancer experts have discovered that prostate
cancer patients who have a lower prostate specific antigen (PSA) score
after radiation therapy are less likely to have their cancer return or
spread to other parts of their body than patients with a higher PSA
score.

Findings from the clinical investigation appeared in the March 15 issue
of the International Journal of Radiation Oncology, Biology and Physics,
a publication of ASTRO, the American Society for Therapeutic Radiology
and Oncology.

The study was conducted on nearly 5,000 patients treated with radiation
therapy in nine well-known academic radiation oncology departments
across the United States. The participating institutions included the
University of Michigan in Ann Arbor; M.D. Anderson Cancer Center in
Houston, Texas; Fox Chase Cancer Center in Philadelphia, Pa.; Cleveland
Clinic Foundation in Ohio; William Beaumont Hospital in Royal Oak,
Mich.; Mallinckrodt Institute of Radiology in St. Louis, Mo.; Mayo
Clinic College of Medicine in Rochester, Minn.; Massachusetts General
Hospital in Boston; and Memorial Sloan-Kettering Cancer Center in New
York City.

After receiving radiation, most patients experience a decline in their
PSA blood test score. Doctors measure the PSA level after radiation to
monitor treatment response. If the PSA decreases and then stays
relatively level, the treatment is considered a success. But if the PSA
then rises, doctors may consider additional treatments for cancer
recurrence.

In this study, researchers set out to examine whether or not a lower PSA
score is a good indicator in predicting the likelihood that a patient's
prostate cancer will return or spread. In the current standard of care,
doctors are less interested in the actual PSA score but in whether the
PSA rises after treatment. A rise is used to gauge whether the cancer
will likely return.

The doctors found that a lower PSA level was associated with a dramatic
decrease in both prostate cancer recurrence and the spread of cancer
among patients across all risk categories. The patients were separated
into different categories based on their PSA score after radiation.

The patients with the lowest PSA scores experienced an eight-year
disease-free survival rate of 75 percent, compared with only 18 percent
for those with the highest PSA scores. Patients who had the lower PSA
scores also had a 97-percent distant metastasis-free survival rate
compared with a 73-percent rate for those with the highest PSA scores.

In addition, the researchers found that patients treated with a higher
dose of radiation had a better chance of achieving a lower PSA score and
were less likely to see their prostate cancer return.

"While there is no magic number for the PSA that guarantees that
prostate cancer has been cured in an individual patient, in general, the
lower the PSA number, the better chances that the cancer will not return
or spread," said Michael E. Ray, M.D., Ph.D., lead author of the study
and a radiation oncologist at the University of Michigan Medical Center.
"These findings may help us to identify high-risk patients early. This
may allow their doctors to consider other adjuvant or salvage therapies
to hopefully increase their chances for survival."

This information was provided by the American Society for Therapeutic
Radiology and Oncology (ASTRO).

knowledge is power - growing old is mandatory - growing wise is optional    
"Many more men die with prostate cancer than of it. Growing old is
invariably fatal. Prostate cancer is only sometimes so."
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