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Roman Bystrianyk
Posted: Wed Nov 15, 2006 8:56 am
Guest
CARLA K. JOHNSON, "Study questions radiation for prostate", Seattle
Post-Intelligencer, November 14, 2006,
Link:
http://seattlepi.nwsource.com/health/1500AP_Radiation_Prostate_Cancer.html

When prostate surgery fails to remove all traces of cancer, men face a
decision about whether to have radiation therapy.

Radiation can lead to bowel and urinary problems, but patients might
find that risk acceptable if there were evidence it guaranteed a
longer, healthier life.

A new study finds no such guarantee. It suggests radiation following
surgery may not make a difference in how long a man lives, or in how
long he lives without his prostate cancer spreading.

Radiation did lessen the chances a man would have an abnormal PSA test,
an abnormal biopsy or other clinical finding showing prostate cancer's
return during the next 10 years, the researchers found.

The findings apply to up to 35,000 American men annually. That's how
many have their prostates surgically removed, but whose followup tests
show some cancer cells may linger in surrounding tissue.

The study will help each of these men "make the decision based on
whether he would want to trade off perhaps some bowel or urinary
complications to reduce his risk of cancer coming back," said study
co-author Dr. Ian Thompson, a urologist at the University of Texas
Health Science Center at San Antonio.

The study, appearing in Wednesday's Journal of the American Medical
Association, was funded by grants from the National Cancer Institute
and the National Cancer Institute of Canada.

Researchers tracked 425 men, ages 43 to 79, for an average of 10 years
following prostate removal. All the men had tests suggesting the
surgery had failed to remove all the cancer cells.

About half the men were randomly assigned to radiation treatment. The
others waited while doctors monitored their blood for PSA, or
prostate-specific antigen, an imperfect test that can indicate prostate
cancer.

Compared to the men who waited, the men who received radiation soon
after surgery cut in half their risk for a later abnormal PSA test or a
finding of cancer.

But the two groups showed no significant difference in survival - or in
how long they lived without cancer spreading to other organs.

The study may have been too small to find a difference in survival,
said Dr. John Concato, a clinical epidemiologist at the VA Connecticut
Healthcare System who was not involved in the study. Or the men's
cancers may not have had a large effect on their life expectancy.

Radiation wasn't a perfect cure. Some men in both groups saw their
cancer spread, or metastasize: 17 out of 214 men in the radiation
group, and 35 out of 211 men in the waiting group.

The study didn't evaluate the cost of the two approaches, but radiation
therapy can cost up to $40,000, Thompson said.

Dr. Anthony D'Amico of Boston's Dana Farber Cancer Institute said he
doesn't expect a change in treatment in the United States because of
the findings, but European doctors might increase their use of
post-surgical radiation or PSA testing, which aren't used as commonly
there.

U.S. doctors will continue to choose radiation for more extreme cases,
and wait until the PSA test shows signs of cancer return for other men,
D'Amico said. He was not involved in the study.

"We have to use some clinical common sense," D'Amico said.

The prostate is a gland the size of a walnut under the bladder that
makes fluid for semen. Prostate cancer is second only to skin cancer in
its prevalence among American men.

About 234,000 U.S. men are expected to be diagnosed with it this year
and just over 27,000 will die of it. A diet high in fruits and
vegetables may reduce the risk.

Also in Wednesday's JAMA, a study from the U.S. Department of Veterans
Affairs found a surprisingly high number of elderly veterans, with no
previous history of prostate cancer, received screening PSA tests.
Current recommendations say doctors shouldn't test men with limited
life expectancies, but researchers found one-third of men older than 85
and in poor health got PSA tests.
Leonard Evens
Posted: Wed Nov 15, 2006 11:31 am
Guest
Roman Bystrianyk wrote:
Quote:
CARLA K. JOHNSON, "Study questions radiation for prostate", Seattle
Post-Intelligencer, November 14, 2006,
Link:
http://seattlepi.nwsource.com/health/1500AP_Radiation_Prostate_Cancer.html

When prostate surgery fails to remove all traces of cancer, men face a
decision about whether to have radiation therapy.

Radiation can lead to bowel and urinary problems, but patients might
find that risk acceptable if there were evidence it guaranteed a
longer, healthier life.

A new study finds no such guarantee. It suggests radiation following
surgery may not make a difference in how long a man lives, or in how
long he lives without his prostate cancer spreading.

Radiation did lessen the chances a man would have an abnormal PSA test,
an abnormal biopsy or other clinical finding showing prostate cancer's
return during the next 10 years, the researchers found.

The findings apply to up to 35,000 American men annually. That's how
many have their prostates surgically removed, but whose followup tests
show some cancer cells may linger in surrounding tissue.

The study will help each of these men "make the decision based on
whether he would want to trade off perhaps some bowel or urinary
complications to reduce his risk of cancer coming back," said study
co-author Dr. Ian Thompson, a urologist at the University of Texas
Health Science Center at San Antonio.

The study, appearing in Wednesday's Journal of the American Medical
Association, was funded by grants from the National Cancer Institute
and the National Cancer Institute of Canada.

Researchers tracked 425 men, ages 43 to 79, for an average of 10 years
following prostate removal. All the men had tests suggesting the
surgery had failed to remove all the cancer cells.

About half the men were randomly assigned to radiation treatment. The
others waited while doctors monitored their blood for PSA, or
prostate-specific antigen, an imperfect test that can indicate prostate
cancer.

Compared to the men who waited, the men who received radiation soon
after surgery cut in half their risk for a later abnormal PSA test or a
finding of cancer.

But the two groups showed no significant difference in survival - or in
how long they lived without cancer spreading to other organs.

The study may have been too small to find a difference in survival,
said Dr. John Concato, a clinical epidemiologist at the VA Connecticut
Healthcare System who was not involved in the study. Or the men's
cancers may not have had a large effect on their life expectancy.

Radiation wasn't a perfect cure. Some men in both groups saw their
cancer spread, or metastasize: 17 out of 214 men in the radiation
group, and 35 out of 211 men in the waiting group.

Note that, if this means what it says, roughly twice as many men in the
no-radiation group had metastases. If so, the only way to make sense of
the conclusion of the study is that the researchers didn't find such a
difference statistically significant. That means that such a difference
could have occurred just by chance. It doesn't mean the study showed
there was no difference. So the conclusion that the study may just not
have been large enough makes sense. Still I find it surprising that a 2
to 1 difference would not be statistically significant. Perhaps the
report was not accurate.

In any case, I think it is a mistake to jump to conclusions on the basis
of any one study. Often different research studies reach different
conclusions and the conclusion of each study is outside the error bars
of the other study. That means one or the other study, or perhaps
both, are just wrong. Eventually, these things are worked out through
further research, and the picture becomes clearer, but it can take time.

Quote:

The study didn't evaluate the cost of the two approaches, but radiation
therapy can cost up to $40,000, Thompson said.

Dr. Anthony D'Amico of Boston's Dana Farber Cancer Institute said he
doesn't expect a change in treatment in the United States because of
the findings, but European doctors might increase their use of
post-surgical radiation or PSA testing, which aren't used as commonly
there.

U.S. doctors will continue to choose radiation for more extreme cases,
and wait until the PSA test shows signs of cancer return for other men,
D'Amico said. He was not involved in the study.

"We have to use some clinical common sense," D'Amico said.

The prostate is a gland the size of a walnut under the bladder that
makes fluid for semen. Prostate cancer is second only to skin cancer in
its prevalence among American men.

About 234,000 U.S. men are expected to be diagnosed with it this year
and just over 27,000 will die of it. A diet high in fruits and
vegetables may reduce the risk.

Also in Wednesday's JAMA, a study from the U.S. Department of Veterans
Affairs found a surprisingly high number of elderly veterans, with no
previous history of prostate cancer, received screening PSA tests.
Current recommendations say doctors shouldn't test men with limited
life expectancies, but researchers found one-third of men older than 85
and in poor health got PSA tests.
Leonard Evens
Posted: Wed Nov 15, 2006 11:44 am
Guest
Roman Bystrianyk wrote:
Quote:
CARLA K. JOHNSON, "Study questions radiation for prostate", Seattle
Post-Intelligencer, November 14, 2006,
Link:
http://seattlepi.nwsource.com/health/1500AP_Radiation_Prostate_Cancer.html

When prostate surgery fails to remove all traces of cancer, men face a
decision about whether to have radiation therapy.

Looking more closely at what the study was looking at reveals that the
headline is very misleading. What was compared was radiation applied
right after surgery in cases where there was evidence the cancer had
spread. But the typical way radiation is used after surgery is to wait
until there is a PSA rise. Then based on various criteria such as how
long before the PSA rose and how fast it rose, doctors may decide to use
radiation. The hope is that the recurrence is lo9cal and can be cured
by radiation. In addition, this would apply to all men who have had
surgery, not just to those who appeared after surgery to be at greater
risk. This study looked instead at the option of applying radiation
prophylactically to the group of men deemed to be at greater risk of
spread because of specific diagnostic criteria, e.g., positive margins
or a high PSA. If the study showed anything, it was that prophylatic
use before PSA actually rises, for a certain class of high risk cases,
doesn't provide a benefit in increased life expectancy or less
likelihood of clinical symptoms of metastasis. There could be lots of
reasons for that. And it doesn't say anything much about the utility of
using radiation, as it usually is, for all men following surgery, once
PSA starts to rise and certain other criteria are met. It may not even
say much about the benefits to the high risk group of using radiation
after PSA rises, since that is not what they did.

Quote:

Radiation can lead to bowel and urinary problems, but patients might
find that risk acceptable if there were evidence it guaranteed a
longer, healthier life.

A new study finds no such guarantee. It suggests radiation following
surgery may not make a difference in how long a man lives, or in how
long he lives without his prostate cancer spreading.

Radiation did lessen the chances a man would have an abnormal PSA test,
an abnormal biopsy or other clinical finding showing prostate cancer's
return during the next 10 years, the researchers found.

The findings apply to up to 35,000 American men annually. That's how
many have their prostates surgically removed, but whose followup tests
show some cancer cells may linger in surrounding tissue.

The study will help each of these men "make the decision based on
whether he would want to trade off perhaps some bowel or urinary
complications to reduce his risk of cancer coming back," said study
co-author Dr. Ian Thompson, a urologist at the University of Texas
Health Science Center at San Antonio.

The study, appearing in Wednesday's Journal of the American Medical
Association, was funded by grants from the National Cancer Institute
and the National Cancer Institute of Canada.

Researchers tracked 425 men, ages 43 to 79, for an average of 10 years
following prostate removal. All the men had tests suggesting the
surgery had failed to remove all the cancer cells.

About half the men were randomly assigned to radiation treatment. The
others waited while doctors monitored their blood for PSA, or
prostate-specific antigen, an imperfect test that can indicate prostate
cancer.

Compared to the men who waited, the men who received radiation soon
after surgery cut in half their risk for a later abnormal PSA test or a
finding of cancer.

But the two groups showed no significant difference in survival - or in
how long they lived without cancer spreading to other organs.

The study may have been too small to find a difference in survival,
said Dr. John Concato, a clinical epidemiologist at the VA Connecticut
Healthcare System who was not involved in the study. Or the men's
cancers may not have had a large effect on their life expectancy.

Radiation wasn't a perfect cure. Some men in both groups saw their
cancer spread, or metastasize: 17 out of 214 men in the radiation
group, and 35 out of 211 men in the waiting group.

The study didn't evaluate the cost of the two approaches, but radiation
therapy can cost up to $40,000, Thompson said.

Dr. Anthony D'Amico of Boston's Dana Farber Cancer Institute said he
doesn't expect a change in treatment in the United States because of
the findings, but European doctors might increase their use of
post-surgical radiation or PSA testing, which aren't used as commonly
there.

U.S. doctors will continue to choose radiation for more extreme cases,
and wait until the PSA test shows signs of cancer return for other men,
D'Amico said. He was not involved in the study.

"We have to use some clinical common sense," D'Amico said.

The prostate is a gland the size of a walnut under the bladder that
makes fluid for semen. Prostate cancer is second only to skin cancer in
its prevalence among American men.

About 234,000 U.S. men are expected to be diagnosed with it this year
and just over 27,000 will die of it. A diet high in fruits and
vegetables may reduce the risk.

Also in Wednesday's JAMA, a study from the U.S. Department of Veterans
Affairs found a surprisingly high number of elderly veterans, with no
previous history of prostate cancer, received screening PSA tests.
Current recommendations say doctors shouldn't test men with limited
life expectancies, but researchers found one-third of men older than 85
and in poor health got PSA tests.
madiba
Posted: Thu Nov 30, 2006 1:20 pm
Guest
Leonard Evens <len@math.northwestern.edu> wrote:

Quote:

Note that, if this means what it says, roughly twice as many men in the
no-radiation group had metastases. If so, the only way to make sense of
the conclusion of the study is that the researchers didn't find such a
difference statistically significant. That means that such a difference
could have occurred just by chance. It doesn't mean the study showed
there was no difference. So the conclusion that the study may just not
have been large enough makes sense. Still I find it surprising that a 2
to 1 difference would not be statistically significant. Perhaps the
report was not accurate.

In any case, I think it is a mistake to jump to conclusions on the basis
of any one study. Often different research studies reach different
conclusions and the conclusion of each study is outside the error bars
of the other study. That means one or the other study, or perhaps
both, are just wrong. Eventually, these things are worked out through
further research, and the picture becomes clearer, but it can take time.

I noticed the 50% reduction in mets in the rad group too, but
(independent of cohort size) this does not automatically mean a
significant survival- or even a met-free survival time difference. The
mets in the few irradiated patients that got them might all have occured
much sooner than in the other group.
--
madiba
 
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