What does it mean to have a Gleason score of 6 (or 7 or 8-10) ?
The lowest Gleason score of a cancer found on a prostate biopsy is 6. These cancers may be called well-differentiated or low-grade and are likely to be less aggressive – they tend to grow and spread slowly.
Cancers with Gleason scores of 8 to 10 may be called poorly differentiated or high grade. These cancers tend to be aggressive, meaning they are likely to grow and spread more quickly.
Cancers with a Gleason score of 7 may be called moderately differentiated or intermediate grade. The rate at which they grow and spread tends to be in between the other 2.
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The use
of active surveillance for the management of nonaggressive prostate cancer has
soared to record highs in Sweden in recent years, providing a
"benchmark" for the rest of the world, according to the authors of a
new study.
From 2009
to 2014, the proportion of Swedish men with very-low-risk cancer choosing
active surveillance increased from 57% to 91% and, among those with low-risk
cancer, it rose from 40% to 74%, report the investigators, led by Stacy Loeb,
MD, MSc, from New York University in New York City. The authors used data from
a nationwide prostate cancer registry.
Low-risk
prostate cancer and its prolonged natural history can be safely managed with
active surveillance and the deferred, as-needed use of curative treatment, such
as prostatectomy and radiation therapy, explain Dr Loeb and her coauthors, who
include academics from three different Swedish universities.
Notably,
in Sweden, medical records distinguish between active surveillance, which
includes blood testing, biopsy, and imaging, and watchful waiting, which is a
passive approach that waits to see whether clinical symptoms develop before
medical intervention.
The new
Swedish active surveillance data, which are an update from an earlier report
that extended only to 2011, are the "highest rates yet reported" and
"should serve as a benchmark to compare the use of active surveillance for
favorable-risk disease around the world," write the authors.
Currently,
the United States does not measure up very well, suggest the authors. Most
low-risk disease is treated immediately, they observe.
"We
hope that our data from Sweden will showcase that…the use of this management
option is growing around the world and will encourage US men who are diagnosed
with low-risk prostate cancer to ask their doctor about it," Dr Loeb told Medscape
Medical News.
Dr Loeb
has been an ongoing supporter of the use of active surveillance. At a press
conference at the 2014 annual meeting of the American Urological Association
(AUA), she declared the "era of active surveillance" had arrived.
This meeting featured multiple studies indicating large upticks in its use.
The new
study from Dr Loeb and colleagues is published online
today in JAMA Oncology.
The high
rate of active surveillance in Sweden "is likely a goal to which we should
aspire on both sides of the Atlantic," says Matthew R. Cooperberg, MD,
MPH, from University of California San Francisco in an accompanying
editorial.
Dr
Cooperberg also says that active surveillance rates "are still too
low" in the United States.
Still,
progress is being made, he suggests.
Dr
Cooperberg says that data from some prospective, community-based registries
have shown use of active surveillance "skyrocketing" to 40% to 50%
for low-risk disease in the current decade, up from historical rates of about
10% (JAMA. 2015;314:80-82).
He also
highlights guidance newly endorsed by the American Society of Clinical Oncology
that surveillance is "not merely an option" for men with low-risk
disease but rather is the "preferred alternative" for any clinically
localized, Gleason 3 + 3 cancer.
But Dr
Cooperberg makes no mention of guidance from the most influential organization
in the United States with regard to prostate cancer: the AUA.
The AUA
has not updated its guidelines for the management of localized prostate cancer,
which include active surveillance recommendations, since 2007.
With
regard to Sweden, the study authors describe some "potential facilitating
factors" for the "rapid uptake" of active surveillance.
For
example, in 2007 national guidelines were issued that recommended active
surveillance for men with low-risk prostate cancer and a life expectancy of 10
to 20 years. Then, in 2014, the life expectancy limit was abandoned, and active
surveillance was recommended for all men with very-low-risk prostate cancer.
The study
authors also believe it is important that Sweden's National Prostate Cancer
Register provides "real-time feedback" to practices on their
adherence to these national guidelines and also in annual reports publicly
available online.
Furthermore,
the Swedish healthcare system "is dominated by equal access, tax-funded
care without financial incentives for clinicians to recommend curative
treatment," the authors observe.
Overall,
32,518 men with a median age of 67 years were diagnosed with favorable-risk
prostate cancer during the study period.
These
included 4693 men with very-low-risk disease (clinical stage, T1c; Gleason
score 6 or less; prostate-specific antigen [PSA], <10 ng/mL; PSA density
<0.15 ng/mL/cm3; and <8-mm total cancer length in 4 positive
biopsy cores).
A total
of 15,403 men with low-risk disease (including all men in the very-low-risk
group) (T1 to T2; Gleason score, 6 or less; and PSA <10 ng/mL), and 17,115
men had intermediate-risk disease (T1 to T2; Gleason score, 7; and/or PSA, 10
to 20 ng/mL).
Use of
active surveillance for intermediate-risk disease was much lower — only 19% of
cases in 2014.
In a
press statement, Dr Loeb said that more US men opting for active surveillance
"could go a long way toward reducing the harms of screening by minimizing overtreatment
of non-aggressive prostate cancer."
Dr
Cooperberg agrees.
In his editorial, he writes: "A default assumption that most
low-risk prostate cancers do not need immediate treatment would completely
shift the balance of benefits and harms for prostate cancer early detection
efforts, and it will prove invaluable in reframing the ongoing national debate
regarding optimal screening policy."
Nick Mulcahy: October 20, 2016
