By
Steven Reinberg
THURSDAY,
July 21, 2016 (HealthDay News) -- A headline-grabbing report earlier this week
claimed that new cases of advanced prostate cancer in the United States had
skyrocketed 72 percent in the past decade.
And the study authors from Northwestern
University suggested the increase might be tied to a 2012 recommendation that
men not be screened for prostate
cancer by using the prostate-specific antigen (PSA) test. PSA,
a protein produced by cells of the prostate
gland, is often elevated in men with prostate cancer. However, the
validity and usefulness of the PSA test has been debated for years.
But on Wednesday, the American Cancer Society
challenged the validity of the Northwestern researchers' findings.
Dr. Otis Brawley, the society's chief medical
officer, said the methodology used by the Northwestern researchers was flawed,
thereby making the study's conclusions flawed.
"This study makes a dramatic claim about
an issue all of us have been watching eagerly: namely, whether less PSA
screening might lead to more advanced cancers. But the current analysis is far
from adequate to answer that question sufficiently," Brawley said in a
news release.
According to Brawley, the usual way such studies
are done is to look at the rate of cases. "But this study, done by a group
of urologists, didn't do that. Rather than measure rates of metastatic disease,
they looked at the number of cases. That is far from the same thing," he
explained.
Brawley added that "you can't simply look
at raw numbers. A rising number of cases can be due simply to a growing
and aging population among other
factors."
In addition, the increase in advanced prostate
cancer cases began before the U.S. Preventive Services Task Force 2012
recommendation that men not be screened using the PSA test.
"There may or may not be a rise in the
rates of metastatic disease; but because of a flawed analysis, this study does
not answer that important question," Brawley said.
The study in question was published July 19 in
the journal Prostate Cancer and Prostatic Diseases. It said the
biggest increase in prostate cancer diagnoses was among men aged 55 to 69, with
a 92 percent jump seen over 10 years.
"The increase could be because the
disease is becoming more aggressive, or it could be because there is less
screening being done, but we don't know why," lead researcher Dr. Edward
Schaeffer said earlier this week. He is chair of urology at Northwestern
University's Feinberg School of Medicine in Chicago.
It's possible that prostate cancer may be
getting more aggressive, Schaeffer said, but statistics also show that fewer
men are being screened. That's the probable consequence of the 2012
recommendation by the U.S. Preventive Services Task Force, the study authors
suggested.
"My major issue with the U.S. Preventive
Services Task Force recommendation was it completely excluded the patient from
the decision-making process," Schaeffer said. "PSA screening saves
lives, period."
However, since advanced cancer cases began
increasing before the 2012 change in the screening recommendation, the
Northwestern researchers couldn't definitively link the increase in cases to
reduced screening alone, Schaeffer said.
Dr. Anthony D'Amico is chief of radiation oncology at
Brigham and Women's Hospital in Boston. He said it's too early to tell whether
less PSA screening has increased the rate of advanced prostate cancer.
"We won't have the answer to that
question until at least 2019," he said.
The American Cancer Society recommends that
men "make an informed decision with their health care provider about
whether to be screened for prostate cancer. The decision should be made after
getting information about the uncertainties, risks, and potential benefits
of prostate cancer screening." The
discussion about screening should take place at:
·
Age 50 for men at
average risk of prostate cancer and are expected to live at least 10 more
years.
·
Age 45 for men at high
risk of developing prostate cancer. This includes African Americans and men who
have a first-degree relative (father, brother or son) diagnosed with prostate
cancer at an early age (younger than age 65).
·
Age 40 for men at even
higher risk (those with more than one first-degree relative who had prostate
cancer at an early age).
After these discussions have taken place, men
who still want to be screened should get the PSA blood test. The digital rectal
exam may also be used as a part of the screening, the cancer society says.
Copyright © 2016 HealthDay. All rights
reserved.
https://www.medicinenet.com/script/main/art.asp?articlekey=197162
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