New Prostate Cancer Test Better at Determining
Candidates for Surveillance
UC San Francisco tool billed as better at
determining risk; could save many at low-risk from treatment that is now
May 8, 2013 - A new genomic test for prostate
cancer, which most often targets older men, can help predict whether men
are more likely to harbor an aggressive form of the disease, according
to a new UC San Francisco study. The test, which improves risk
assessment when patients are first diagnosed, can also aid in
determining which men are suitable for active surveillance – a way of
managing the disease without direct treatment.
Prostate cancer often grows slowly, and many of the
quarter-million patients diagnosed annually in the United States never
need treatment, which typically involves surgery, radiation or both.
Still, most patients with low-risk prostate cancer in this country
immediately undergo treatment.
The researchers found the new test provides
"statistically significant and clinically meaningful" prognostic
information, and can help identify many more low-risk men who could
safely choose surveillance, sparing them from unnecessary treatment and
avoidable adverse side effects. At the same time, the test can pinpoint
men at apparent low-risk who in fact may have potentially aggressive
tumors, the authors said.
The independent UCSF clinical study of 395 men
validated the Oncotype DX Genomic Prostate Score (GPS), a biopsy-based
pretreatment tool of Genomic Health, Inc. as a predictor of high grade
or extracapsular prostate cancer.
Results will be presented on May 8, 2013, during
the American Urological Association's annual meeting in San Diego.
"With the new test, we can more confidently
recommend active surveillance when it is appropriate,'' said the study's
lead author Matthew R. Cooperberg, MD, MPH, a UCSF assistant professor
of urology and epidemiology & biostatistics. "And patients through
active surveillance can avoid or delay surgery or radiation for their
"Active surveillance is increasingly acknowledged
as a preferred strategy for most men with low-risk disease, but in
practice it is used relatively infrequently," he noted.
"There are many reasons why – financial, legal and
cultural among others. Many men don't want to live with anxiety over the
chances of their disease progressing. So we need to predict with better
accuracy which tumors harbor metastatic potential. If we are able to
risk-stratify men more consistently and identify a greater proportion
for active surveillance, we should be able to ameliorate overtreatment
rates, and by extension help resolve the ongoing debate about PSA
The second most common cancer in men, prostate
cancer affects about one man in six, according to the American Cancer
Society. Typically the disease occurs in older men – the average age at
diagnosis is about 67 – and an aggressive form kills as many as 30,000
men annually in the U.S. Most men, however, do not die from the disease
because they have relatively indolent, low-risk tumors that do not
progress even without treatment.
Active surveillance involves closely monitoring a
patient's condition through serial PSA screening and prostate biopsies,
but otherwise the disease is not treated unless tests show the condition
is getting worse. Active surveillance is not entirely benign – biopsies
are uncomfortable and carry a risk of bleeding and infection. Moreover,
some patients experience a higher level of anxiety over the potential of
their cancers to advance.
While active surveillance can help patients avoid
or delay surgery or radiation, scientists have faced a major challenge:
how to identify – consistently and reliably – which patients can safely
embark on it and which patients face clinically meaningful risk of
In the new UCSF study, investigators evaluated the
ability of the 17-gene assay through prostate needle biopsy specimens to
predict pathologic stage and grade at prostatectomy. The researchers
focused on whether the test's biomarkers added independent predictive
information beyond what could already be determined about a patient
through standard PSA, Gleason grade and biopsy detail variables.
The men in the study, identified from the UCSF
Helen Diller Family Comprehensive Cancer Center Urologic Oncology
Database, ranged from 38 to 77 years old at the time they were diagnosed
– the median age was 58. The patients represented a range of low and
intermediate risk tumors in terms of clinical risk characteristics.
The researchers found that the test "contributed
statistically significant, and clinically meaningful, additional
prognostic information above and beyond existing, previously
well-validated clinical risk stratification instruments."
The authors noted a number of study limitations
including an explicit intention to include men whose tumors were
expected to show a wider range of risk. Further, they said with
additional study, the test might be used to identify men with
particularly low risk tumors who might be candidates for less-intense
surveillance requiring – for example – fewer biopsies.
The test is now available to physicians and
"Prostate cancer is under great scrutiny by many –
patients, providers and others in the health care industry," said senior
author Peter R. Carroll, MD, MPH, professor and chair of the UCSF
Department of Urology.
"Although mortality rates have declined 40
percent since the advent of PSA testing, it has come at the expense of
identifying many men with very low grade, slow growing cancers that
would not have required treatment if their cancers were left undetected.
Over-detection is compounded by over-treatment, the treatment of such
slow growing cancers. Because of this, many have argued that we stop
using serum PSA, but this would reverse the gains in survival witnessed
over the last two decades.
"The way forward is to promote more personalized
decision-making, information not currently available and unique to an
individual's cancer. Such information will allow both patients and
providers to better balance the risks and benefits of either treatment
or careful surveillance in lieu of immediate treatment."
Other UCSF authors are Janet E. Cowan, a program
analyst and CaPSURE Scholars Coordinator; Jeffry P. Simko, MD, PhD,
associate professor of pathology and urology; June M. Chan, ScD, a
professor of urology, epidemiology and biostatistics; and Imelda
Tenggara-Hunter, director of Research Resources in the UCSF Department
Genomic Health, Inc. performed the genomic tests
described in the study and provided financial support to UCSF to help
defray tissue, data processing and pathology costs. No non-Genomic
Health author received any personal compensation for the study nor do
any non-Genomic Health investigators stand to benefit financially from
the publication of the study. The research was also supported indirectly
by Department of Defense grant PC101769.
UCSF is a leading university dedicated to promoting
health worldwide through advanced biomedical research, graduate-level
education in the life sciences and health professions, and excellence in
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