MONDAY, June 6 (HealthDay News) -- There's too little evidence
to say definitively whether treating early, localized prostate
cancer with radiation is a better option than "watchful waiting,"
new research finds.
In a study funded by the Agency for Healthcare Research and
Quality (AHRQ), researchers from Tufts University reviewed the
available literature on radiation and prostate cancer, including 10
randomized controlled trials and 65 observational studies.
They concluded there was "insufficient evidence" to say with
certainty whether radiation treatment compared to watchful waiting
is more likely to save lives.
"We just don't have sufficient information to say much of anything," said Dr. Stanley Ip, an assistant professor of medicine at Tufts University Medical Center.
In part, that's because researchers found no randomized
controlled trials -- considered the gold standard of research --
that compared radiation therapy with watching waiting, Ip said.
Though there were observational studies, those may be biased
because men who opt to hold off on treatment may be those whose
tumors are lower risk to begin with, he said.
The study is published in the June 6 issue of the
Annals of Internal Medicine.
Watchful waiting -- which does not involve cancer treatment --
means having regular exams while keeping an eye on the tumor to see
if it grows or spreads. It is usually recommended when doctors feel
someone's advanced age will allow them to outlive the generally
slow-moving cancer or when someone has other conditions that are
more likely to prove lethal.
Men who are diagnosed with early prostate cancer -- meaning it's
confined to the prostate gland and has not spread -- are confronted
with a bewildering array of options for treating it: surgery;
radiation; drugs to deprive the tumor of the hormone androgen that
may drive its growth; or watchful waiting.
In 2008, AHRQ also commissioned a review of studies on other
prostate cancer treatment options, but that report could not draw
conclusions on the best approach either.
"What all of these analyses have found is there is very limited data that allows us to determine which of these approaches in the best approach," said Dr. Durado Brooks, director of prostate cancer for the American Cancer Society.
Brooks said more comparative effectiveness research, which
compares different kinds of treatments, is needed.
In the meantime, what are men diagnosed with early prostate
cancer to do?
Men and their doctors need to consider what the tumor looks like
under the microscope, which can help gauge how aggressive it may
be. They should also consider age and overall health status,
including whether or not the patient has other conditions more
likely to cause death than the prostate cancer.
Finally, patients and their doctors should weight the potential
debilitating side effects of the treatments, such as incontinence
and erectile dysfunction, against how comfortable the man is with
holding off on treatment, experts say.
"Men need to learn as much as they can about the possible outcomes and benefits of the various treatments and the potential side effects, and choose which direction they are most comfortable with," Brooks said.
In the current review, researchers found several trials that
compared different doses of radiation and different types of
radiation therapy, including external beam radiation therapy, in
which a radiation is delivered through a beam through the skin, or
brachytherapy, in which radioactive isotopes are delivered via
injection into the prostate.
For those methods, too, there was too little research to say
with confidence which method was superior in preventing deaths from
prostate cancer, the researchers said. Retrospective studies,
however, found that radiation treatments were associated with
increased urinary or bowel problems, compared with no treatment or
no initial treatment.
There was also "moderate strength evidence" that a higher
external beam radiation was more effective than a lower dose.
Taken together, the review "does point out that based on current
evidence, doctors should not be telling their patients that this
form of radiation is better than that form," Brooks said. "Some of
the distinctions being made are not really supported by the
Proton beam therapy in particular is expensive, but according to
this report, there isn't enough evidence to show it's any better
than other option.
Radiation, he noted, may be the best option for men whose tumors
have spread outside the gland, since simply removing the prostate
gland surgically is not likely to be as effective, he said.
The American Cancer Society estimates that in 2009,
approximately 192,000 men were diagnosed with prostate cancer and
approximately 27,000 men died of the disease.
National Cancer Institute has more on prostate