Hormones Delay Prostate Cancer Growth
Short-Term Androgen Deprivation Therapy Has Long-Term Benefits
Jan. 2, 2008 -- Short-term hormone therapy to lower testosterone levels can
significantly delay the progression of prostate
cancer in some patients treated with radiation, a study shows.
Just four months of androgen deprivation therapy (ADT) before and during
radiation was found to slow cancer growth by as much as
eight years in patients with high-risk, locally advanced disease. The patients
had either declined or were not considered candidates for longer-term hormonal
treatment, researcher Mack Roach III, MD, of the University of California San
Francisco, tells WebMD.
The findings were reported today in the American Society of Clinical
Oncology (ASCO) publication Journal of Clinical Oncology.
ADT and Heart Risk
The researchers also found no evidence of an increase in heart risk among
the hormone-treated patients, compared with patients treated with radiation
This finding should allay concerns about the treatment raised by a recent
study, Roach tells WebMD.
In mid-October, Harvard researchers reported that short-term ADT prior to
prostate cancer surgery was associated with a more than twofold increase in
death from cardiovascular causes in men with localized disease.
That study did not include patients treated with ADT and radiation, and
there is no clinical evidence of an increase in cardiovascular risk in these
patients, Roach says.
"Our findings clearly show that the benefits [of short-term hormone
treatment] outweigh the risks in this group of patients," Roach tells
WebMD. "If there is an increase in heart
attack risk, we didn't see it in this long-term follow-up."
8-Year Delay in Progression
The goal of ADT is to lower levels of the male sex hormones, which fuel the
growth of prostate cancer.
Long-term hormone suppression of two years or more has been shown to improve
survival in prostate cancer patients treated with radiation who are considered
high risk due to high tumor burden, high prostate-specific antigen (PSA)
scores, or other prognostic indicators.
But long-term ADT is also associated with an increased risk for
osteoporosis, diabetes, and other health problems.
In an effort to assess the risks vs. benefits of shorter-term ATD, Roach and
colleagues followed 456 older men with high-risk prostate cancer for 13
Roughly half the men were treated with ADT for four months, immediately
before and during radiation treatment. The rest of the patients were treated
with radiation alone.
After about five years of follow-up, 40% of patients treated with radiation
alone had cancer that had spread to the bones. It took an additional eight
years for the same percentage of patients treated with ADT and radiation to
develop bone metastases, says Roach.
Fewer prostate cancer deaths were reported in ADT-treated patients over 10
years of follow-up, and these men were also more likely to show no evidence of
disease after 10 years.
Fatal cardiac events occurred in 12.5% of the ADT-treated patients, compared
with 9.1% of the patients treated with radiation alone -- a difference that
could have been due to chance.
"Men who took hormone therapy were 25% more likely to be alive after 10
years," Roach tells WebMD.
The findings confirm the long-term benefits of short-term ADT when combined
with radiation, University of Michigan radiation oncology professor Howard
Sandler, MD, tells WebMD.
"Even when hormone therapy is used for only four months, the benefits of
hormones and radiation can last for many years," he says.
Sandler recommends two to three years of ADT for his highest-risk patients,
but he says short-term hormone therapy appears adequate for patients at the
higher end of the intermediate-risk scale.