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Prostate cancer has been an ignored disease for too long. What follows
is evidence I use to support the concept of early detection with the
present available tools. Although I decided to treat my cancer at
diagnosis, I believe that is for each patient to decide to be treated
or not. Prefereably from a knowledge base and not from fear or
ignorance.
Evidence supporting early detection for prostate cancer
The negativity against early detection is driven by the US
Preventive Services Task Force (USPSTF). This agency issued
recommendations in 1996 and later updated the information in 2002.
There is a certain hint of provinciality here in the U.S.A., if a study
or clinical trial is not conducted in this country.
Evidence based medicine cannot be provincial as long as the studies
are well designed and recognized as such by medical authorities. As it
happens many key studies about the natural course of untreated prostate
cancer were conducted in EU countries in which prostate cancer was not
aggressively treated.
This information is vital to the issue of screening and early
detection. Saying that it is not an American product is an anomaly when
globalization is progressing at an accelerated rate and the world is
becoming smaller by trading and communications. It is important
therefore to review the recommendation of the USPSTF and counter them
with current supporting evidence, irrelevant of origin.
Significant issues:
1. Prostate cancer mortality and its association with testing.
Since the inception of PSA testing in late 80s and more frequent
use in the early to mid 90s, the mortality rate for prostate cancer has
been reduced by more than 32% between 1993 and 2003. One of the
critical aspects of the USPSTF recommendation is the inconclusive
evidence that early detection improves health outcomes. The "real"
evidence suggests that in spite of the expressed "widespread" use of
PSA testing only 41% of men age 50 or above admit having a PSA within
the last year. Men age 50 to 64 had a worse score. Only 33.6% admitted
to have a test within the last year. In men 65 and above the figure is
51.3%. This alone is an indication that the "modest" reduction in the
mortality rate is not that modest after all considering that the use of
PSA is less common than proclaimed.
Source: Swan J, Breen N, Coates RJ, Rimer BK, Lee NC. Progress in
cancer screening practices in the United States: results from the 2000
National Health Interview Survey. Cancer. 2003 Mar 15;97(6):1528-40.
PMID: 12627518 [PubMed - indexed for MEDLINE]
More recently the Cancer Prevention Fellowship Program, Division of
Cancer Prevention and Health Communication and Informatics Research
Branch, Division of Cancer Control and Population Science, National
Cancer Institute, Bethesda published that 44.8% of men ages 50 to 75
had never had a PSA test in their life. Hardly widespread use in my
view...and this fits the picture that we see at the support group level
with many men diagnosed with more advanced disease than they should.
One of the main arguments I use against those that negate the value of
screening , early detection and early treatment is the unexplained
reduction of prostate cancer deaths since the inception of what I
define as limited detection by PSA testing. Request those opposing you
to explain the reduction in mortality and the possibility to reduce
deaths if more men
would be tested.
Evidence based medicine as expressed by the USPSTF seems to have
selective biases in deciding what is good or bad and tends to ignore or
minimize preliminary evidence. Such is the case with the extensive
experiment carried out in Tyrol, Austria. This is a recent update of
the study now going into its 12th year:
In 1993, a mass screening project using PSA as the only screening
test was launched in the Federal State of Tyrol (one of nine federal
states of the Republic of Austria). The aim of the Tyrol study was to
monitor the impact of screening in a natural experiment by comparing
prostate cancer mortality in Tyrol, where prostate-specific antigen
(PSA) testing was introduced at no charge, with the rest of Austria,
where it was not strictly organized and not free of charge. In 1993,
PSA testing was made freely available to men between the ages of 45 and
75 years in the Federal State of Tyrol, Austria. Initially, only total
PSA was measured, but free PSA measurement was added in 1995.
All of the men in this age range were advised and encouraged to
undergo PSA testing; information to this effect was distributed to
every Tyrolean man through print, radio, and television. The screening
project was performed in collaboration with general practitioners,
medical examiners, urologists, medical laboratories, and the Tyrol
Blood Bank of the Red Cross. Informed consent was obtained from all of
the volunteers participating in the program. During 1993, when PSA
testing became freely available, 32.3% of all Tyrolean men between the
ages of 45 and 75years underwent PSA screening and at least 70% of this
population was tested at least once during the first 10 years of the
study.
Tyrol is an alpine region in Western Austria with 631,410
inhabitants (at the 1991 census; 324,161 women and 307,249 men) in an
area of 12,647 square kilometers. More than 96,000 men were screened at
least once between 1993 and 2001. Of these men, 10,100 were between the
ages of 45 and 49 and 4,900 were between 40 and 44 years of age. Thus,
a substantial number of men between the ages of 40 and 44 were
screened, justifying the inclusion of this age group in the analysis of
the incidence and mortality rates.
From 1993 to 2001, 6024 transrectal prostate needle biopsies were
performed. The overall prostate cancer detection rate was 30.2%. The
incidence of prostate cancer in men between the ages of 40 and 79 in
Tyrol increased from 1988 to 1994 and has remained constant. The
incidence of organ-confined disease (stages 1 and 2) continued to
increase from 1988 until 1998, although the incidence of extraprostatic
disease (stage 3) declined after a peak in 1994. The incidence of
metastatic disease (stage 4) has been declining since 1993. Since the
beginning of the screening project, a significant migration to lower
total PSA levels in patients undergoing radical prostatectomy has been
observed. Subsequently, the rate of organ-confined disease in radical
prostatectomy increased from 28.7% in 1993 to more than 80% in 2002.
The mortality from prostate cancer in Tyrol decreased significantly
between 1993 and 2000, in contrast to a modest downward trend in
prostate cancer death rates observed in the rest of Austria. On the
basis of the age-specific prostate cancer mortality rates in Tyrol
between 1986 and 1990, 39.6% fewer prostate cancer deaths in the age
range of 40 to 79 years occurred in 1998 through 2000 than were
expected.
The continued increase in local disease incidence, indicating that
PSA testing detects early disease, and the constant decline in the
incidence of prostate cancer that has distant spread at diagnosis in
the population are encouraging. The decrease in prostate cancer
mortality rates in Tyrolean men contrasts with the more modest change
taking place among all men of the same age in the rest of Austria and
provides evidence that screening and early intervention saves lives.
Why then ignore this evidence? Those opposed will tell you that none of
the treatments have been shown to improve survival (even though this is
not totally true). This study is a unique experiment in that a whole
community (a province of a country) was TESTED AND TREATED if
diagnosed. The reduction in mortality there proves that early detection
and early treatment saves lives. Such evidence should and cannot not be
ignored.
Source:
Georg Bartsch, MD
Screening for Prostate Cancer: Updated Experience from the Tyrol Study
Current Urology Reports 2004, 5:220-225
Current Science, Inc. ISSN 1527-2737
Another piece of evidence comes from the U.S. in Olmsted County,
Minnesota where early intervention by testing with PSA and DRE has been
associated with a reduction in the mortality rate in that community.
Source:
Roberts RO, et al., Decline in Prostate Cancer Mortality from 1980
to 1997, and an update on Incidence Trends in Olmsted County,
Minnesota. The Journal
of Urology; Vol. 161, 529-533, 1999.
2. Shift in diagnostic stage and its effects in outcome after treatment
Prior to the more frequent utilization of the PSA test (just 15
years ago) 70% to 80% of men diagnosed with prostate cancer were
diagnosed with advanced stages of the disease. Now, because of more
frequent use of PSA and DRE, 70% to 75% of men are diagnosed with
earlier stages. There is no question that PSA and DRE are responsible
for this shift in stage at diagnosis. There is also evidence that the
outcome of treatment is better in lower stages of the disease.
Obviously, treating an early stage represents an advantage in survival
and impacts the mortality rate. To deny screening is to return to the
past and the high rates of advanced disease.
Sources:
Gilliland FD, et al. Male genital cancers. Cancer. 1995 Jan 1;75(1
Suppl):295-315
Bianco FJ Jr, Wood DP Jr, Grignon DJ, Sakr WA, Pontes JE, Powell IJ.
Prostate cancer stage shift has eliminated the gap in disease-free
survival in black and white American men after radical prostatectomy.
J Urol. 2002 Aug;168(2):479-82.
PMID: 12131292 [PubMed - indexed for MEDLINE]
Catalona, W. J., Smith, D. S., Ratliff, T. L. and Basler, J. W.:
Detection of organ-confined prostate cancer is increased
through prostate-specific antigen based screening. JAMA,
270: 948, 1993
Gretzer, M. B., Epstein, J. I., Pound, C. R., Walsh, P. C. and
Partin, A. W.: Substratification of stage T1C prostate cancer
based on the probability of biochemical recurrence. Urology,
60: 1034, 2002
The 5-year PSA-free survival rate for organ-confined PCa is 86% to
95% as compared to 78% for cancer with microscopic extraprostatic
extension and 43% for those with seminal vesicle involvement. It is
therefore very possible to extend survival by simply treating men
before the disease escapes the prostate. If we add information such as
the treatment results from The Lancet study, which showed a significant
advantage to surgical treatment over conservative management for high
grade PCa, we can be a bit more optimistic about the future of PCa and
a reduction of the mortality rate.
Source:
Lu-Yao G. et al., Population-based study of long term survival in patients
with clinically localized cancer. The Lancet 1997; 349:906-910
Ohori M, et al Prognostic significance of positive surgical margins in
radical prostatectomy specimens. J Urol. 1995 Nov; 154(5):1818-24.
3. The overdiagnosis of prostate cancer. One more smoke screen
The more screening with PSA and DRE the higher the detection
probability. Those that oppose screening claim that what they classify
as a non-specific and non-sensitive marker (PSA) detects too many
cancers that will not affect the patient in their life time. If this
sounds like an oxymoron, it is because it really is. There is no doubt
that over detection will occur. The real issue is what is the rate of
over detection? Wild, off the wall anti-screening entities claim
figures in the 50% to 80%. This is far from reality and they know it.
If one accounts for the lack of "widespread" screening as mentioned
above and the unexplained reduction in the mortality rate since the
increased us of PSA testing, how could such high rates of overdiagnosis
exist? Those overdiagnosed men would not affect the mortality rate by
their classification of indolent cancers. Etzioni et al reported more
rational rate of 15% to 37% at best depending on race.This is one more
excuse without medical basis...
Source:
Ruth Etzioni, David F. Penson, Julie M. Legler, Dante di Tommaso, Rob Boer,Peter H. Gann, Eric J. Feuer
Overdiagnosis Due to Prostate-Specific Antigen
Screening: Lessons From U.S. Prostate Cancer Incidence
Trends. Journal of the National Cancer Institute, Vol. 94, No. 13, July 3, 2002
4. Other issues that qualify as Myths
A. Prostate cancer is an old man's disease.
Life expectancy in men is going up. At the beginning of the
twentieth century male life expectancy was 57 years. At the end of the
century it was 72 years. An extra 26% was added to the life span in one
century alone. For most of written history, life expectancy in general
was about 35 years, but technological advances such as antibiotics and
vaccines and the improvement in hygiene and sanitation have had a
tremendous health impact.
True, the risk and incidence of prostate cancer increase with age,
but a full 25% of prostate cancers are found in men below the age of
65. Now, that represents around 40 to 50 thousand men every year
diagnosed in their working years, the prime of life. Old age is now a
moving threshold. As the population's general health improves and men
avoid death from other causes, the risk of prostate cancer becomes more
significant and awareness about such risk needs to be intensified.
Source:
Cancer Facts & Figures 2005 -The American Cancer Society
B. Most men die with prostate cancer rather than from prostate cancer.
This statement is a piece of misinformation in itself. Why? Because
it ignores the fact that the prostate cancer that kills men is not the
type of cancer commonly found at autopsy of men who die of other causes
without ever showing any sign or symptom of prostate cancer. The type
of cancer found merely at autopsy IS NOT histologically or in size
comparable to the clinically significant cancer that progresses - and
does so at a rate that causes death. All too conveniently, critics
ignore this simple fact and use the prevalence of cancerous prostate
cells to misinform and confuse the issue.
Source:
Villers A, et al [Prostate cancer screening (III): risk factors, natural
history, course without treatment. Characteristics of detected cancers].
Prog Urol. 1997 Sep;7(4):655-61. Review. French.
Sakr WA, et al The frequency of carcinoma and intraepithelial
neoplasia of the prostate in young male patients. J Urol. 1993
Aug;150(2 Pt 1):379-85.
C. Early detection and treatments have not been proven to improve survival.
This has been used widely to avoid the cost of screening. As mentioned in
references above, the Tryrol study has demonstrated survival. The
Olmsted County study also did. A newly reported update of the Holmberg
study showed both disease-specific and overall survival benefit by
those treated with surgery. This is a randomized clinical trial which
cannot be ignored. For the first time a treatment for PCa demonstrated
a survival benefit. Opponents to early detection and treatment keep
ignoring the evidence. This is the world-wide confusion that is like an
anchor around the neck of men at risk of prostate cancer...
Source:
N Engl J Med. 2005 May 12;352(19):1977-84.
Bill-Axelson A, Holmberg L, Ruutu M, Haggman M, Andersson SO, Bratell S,
Spangberg A, Busch C, Nordling S, Garmo H, Palmgren J, Adami HO, Norlen BJ,
Johansson JE; Scandinavian Prostate Cancer Group Study No. 4.
Ralph Valle, Phoenix, Arizona
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PCRI Harry Pinchot Award for dedication and support to the prostate cancer community.
