Radiotherapy After Surgery for T3 Prostate Cancer Shows Trend to
Benefits

By Ed Susman

SAN ANTONIO, TX -- May 31, 2005 -- In a trial that was originally
designed in 1985, researchers found that adjuvant radiotherapy appeared
to benefit men who undergo prostatectomy in cases where the cancer
extends to the margins of the prostate or where there is seminal vesicle
invasion.

While the risk of the development of metastatic disease was reduced by
20% after 10 years, the difference did not reach statistical
significance, said Ian Thompson, MD, Professor and Chairman, Department
of Urology, University of Texas Health Science Center, San Antonio,
Texas, United States.

Dr. Thompson presented the findings here on May 29th at the American
Urological Association (AUA) Annual Meeting. The study included 431 men
who underwent radical prostatectomy between 1988 and 1995, who were
followed for an average of 9.7 years.

After 10 years, 71% of men who receiving radiation were free of
metastases compared to 61% of those who were randomized to observation,
he said. That difference achieved a P = .17 value, not considered
significant.

Overall mortality at 10 years was reduced by 24% in patients who
received radiation, for an overall survival rate of 74% compared to 63%
in men who were assigned to observation (P = .11).

After 10 years, 47% of men who received radiation had any measurable
prostate specific antigen (PSA) compared to 23% of men who were
observed. That 50% reduction did reach statistical significance (P <
001).

However, because the primary endpoint did not reach statistical
significance, "a purist would say that secondary endpoints would also be
non significant," Dr. Thompson noted.

However, he said that being PSA-free was clinically significant to
patients.
"In a man who has had a radical prostatectomy, the development of a
measurable PSA is a bad thing," Dr. Thompson said in a press briefing.
"It leads to anxiety on his part, and we know that if you develop a PSA
recurrence you are at risk of metastatic disease. Measurable PSA
oftentimes leads to other events -- hormonal therapy, subsequent
radiotherapy and other treatments thereafter."

In the trial, 32% of the men who were originally assigned to observation
eventually underwent radiotherapy due to a finding of measurable PSA or
recurrence.

The complexity of making medical choices based on the study were
challenged further by the finding that adverse effects, particularly
bowel and urinary complications, occurred twice as often in men who
underwent radiotherapy. And the men on radiation therapy had lower
quality of life scores, although the difference disappeared after 2
years.

Dr. Thompson said the study shows that doctors and patients have to
engage in serious risk-benefit discussions before deciding on which
treatment option to follow if they are facing a post-surgical decision
after excising T3 prostate cancer.
The study was conducted by the National Cancer Institute-supported
Southwestern Oncology Groups.

[Presentation title: Adjuvant Radiotherapy for Pathologic T3 Prostate
Cancer: Results of a Randomized, Prospective Clinical Trial With
Metastasis-Free
Survival Endpoint. Abstract 1665]    

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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