SUNDAY, June 3 (HealthDay News) -- Men with metastatic prostate
cancer who undergo hormone-deprivation therapy sometimes take
breaks from the treatment to minimize its often difficult side
However, a major new study that tracked more than 1,500 men for
almost a decade finds that opting for intermittent treatment may
take a toll on certain patients, in terms of shortened
The study found that for men with cancer involving "minimal
spread," adopting a stop-and-start treatment schedule was
associated with a two-year decline in survival compared to men
who'd been treated on a continuous basis.
This gap in survival did not appear for men whose prostate
tumors showed more extensive spread, but the researchers stopped
short of recommending intermittent treatment for this subset of
patients, pending better data.
The study, funded by the U.S. National Cancer Institute, was
reported Sunday at the annual meeting of the American Society of
Clinical Oncology (ASCO) in Chicago.
According to the American Cancer Society, prostate cancer is the
second most common cancer in men after skin cancer, with almost
242,000 new cases diagnosed in the United States each year.
Doctors have long known that prostate tumors "feed" on
circulating male hormones such as testosterone. So hormonal
deprivation therapy -- designed to turn off testosterone production
and thereby stop cancer growth -- remains a common first-line
approach in keeping the cancer at bay.
But, there's a big downside to the treatment, since it "is
associated with significant side effects, including loss of libido,
erectile dysfunction, osteoporosis, muscle wasting, hot flashes,
depression and cardiovascular issues," said Dr. Herbert Lepor,
chairman of the department of urology at New York University School
of Medicine in New York City.
He said that in prior studies, "intermittent therapy was equally
effective as continuous therapy with fewer side effects," and so
patients have sometimes opted for this approach.
But, would the intermittent approach remain equally effective
over the long term?
The new phase 3 trial sought to answer that question. In the
study, researchers tracked outcomes for more than 1,500 men with
hormone-sensitive cancers that had spread beyond the prostate. All
of the men first got seven months of continuous hormone deprivation
therapy. Then, half were randomly chosen for intermittent
treatments while the other half stayed on the continuous
Overall, the men who got the stop-and-start treatment were
exposed to about half the total amount of hormonal therapy as the
men in the continuous group, the researchers said.
Unfortunately, "survival with intermittent hormone therapy was
inferior to survival with continuous hormone therapy," reported
study author Dr. Maha Hussain, a professor of medicine and urology
at the University of Michigan Comprehensive Cancer Center.
Speaking at an ASCO press briefing, she concluded that "because
of these findings, continuous therapy continues to be the standard
After a median follow-up of more than nine years, overall
survival in men with minimal disease spread (no cancer beyond the
spine, pelvis and lymph nodes) was 7.1 years for those on
continuous therapy vs. 5.2 years for those treated intermittently
-- a two-year difference.
That gap in survival closed for men with more extensive disease
(4.4 years for those on continuous therapy vs. 5 years for those in
the intermittent group). However, Hussain was careful not to
recommend treatments breaks, even for this sicker group of
patients, saying that the finding was "surprising" and more data is
For patients with extensive cancer spread, it's best to discuss
treatment options with a doctor before embarking on either one of
the regimens, she said.
Dr. Bruce Roth, a professor of medicine in the division of
oncology at Washington University School of Medicine in St. Louis,
said experts had waited a long time for the findings of this
"Prior, underpowered studies suggested that there was no
downside to intermittent therapy, which clearly provides less
toxicity," he said at the press briefing. "This study for the first
time indicates that there is a price to pay."
Lepor agreed that, "on the basis of this study, intermittent
androgen [hormonal] deprivation therapy should no longer be
recommended for those men with minimal disease spread."
Findings presented at medical meetings are typically considered
preliminary until published in a peer-reviewed journal.
There's more on treatments for prostate cancer at the
American Cancer Society.