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Samuel S. Epstein, Rosalie Bertell, and Barbara Seaman
International Journal of Health Services, 31(3):605-615, 2001.
Mammography screening is a profit-driven technology posing risks compounded
by unreliability. In striking contrast, annual clinical breast
examination
(CBE) by a trained health professional, together with monthly
breast self-examination (BSE), is safe, at least as effective,
and low
in cost. International programs for training nurses how to perform
CBE and teach BSE are critical and overdue.
Contrary to popular
belief and assurances by the U. S. media and the cancer establishment- the
National Cancer Institute (NCI) and American Cancer Society (ACS)- mammography
is not a technique for early diagnosis. In fact, a breast cancer
has usually been present for about eight years before it can finally
be detected. Furthermore, screening should be recognized as damage
control, rather than misleadingly as "secondary prevention."
DANGERS
OF SCREENING MAMMOGRAPHY
Mammography poses a wide range of risks
of which women worldwide still remain uninformed.
Radiation Risks
Radiation from routine mammography poses significant cumulative
risks of initiating and promoting breast cancer (1- 3). Contrary
to conventional assurances that radiation exposure from mammography
is trivial- and similar to that from a chest X-ray or spending
one week in Denver, about 1/ 1,000 of a rad (radiation-absorbed
dose)- the routine practice of taking four films for each breast
results in some 1,000-fold greater exposure, 1 rad, focused on
each breast rather than the entire chest (2). Thus, premenopausal
women undergoing annual screening over a ten-year period are exposed
to a total of about 10 rads for each breast. As emphasized some
three decades ago, the premenopausal breast is highly sensitive
to radiation, each rad of exposure increasing breast cancer risk
by 1 percent, resulting in a cumulative 10 percent increased risk
over ten years of premenopausal screening, usually from ages 40
to 50 (4); risks are even greater for "baseline" screening at younger
ages, for which there is no evidence of any future relevance. Furthermore,
breast cancer risks from mammography are up to fourfold higher
for the 1 to 2 percent of women who are silent carriers of the
A-T (ataxia-telangiectasia) gene and thus highly sensitive to the
carcinogenic effects of radiation (5); by some estimates this accounts
for up to 20 percent of all breast cancers annually in the United
States (6).
Cancer Risks from Breast Compression
As early as 1928,
physicians were warned to handle "cancerous breasts with care- for
fear of accidentally disseminating cells" and spreading cancer
(7). Nevertheless, mammography entails tight and often painful
compression of the breast, particularly in premenopausal women.
This may lead to distant and lethal spread of malignant cells by
rupturing small blood vessels in or around small, as yet undetected
breast cancers (8).
Delays in Diagnostic Mammography
As increasing
numbers of premenopausal women are responding to the ACS's aggressively
promoted screening, imaging centers are becoming flooded and overwhelmed.
Resultingly, patients referred for diagnostic mammography are now
experiencing potentially dangerous delays, up to several months,
before they can be examined (9).
UNRELIABILITY OF MAMMOGRAPHY
Falsely
Negative Mammograms
Missed cancers are particularly common in premenopausal
women owing to the dense and highly glandular structure of their
breasts and increased proliferation late in their menstrual cycle
(10, 11). Missed cancers are also common in post-menopausal women
on estrogen replacement therapy, as about 20 percent develop breast
densities that make their mammograms as difficult to read as those
of premenopausal women (12).
Interval Cancers
About one-third of
all cancers- and more still of premenopausal cancers, which are
aggressive, even to the extent of doubling in size in one month,
and more likely
to metastasize- are diagnosed in the interval between successive annual mammograms
(2, 13). Premenopausal women, particularly, can thus be lulled into a false sense
of security by a supposedly negative result on an annual mammogram and fail to
seek medical advice.
Falsely Positive Mammogram
Mistakenly diagnosed cancers
are particularly common in premenopausal women, and also in postmenopausal women
on estrogen replacement therapy, resulting in needless anxiety, more mammograms,
and unnecessary biopsies (14, 15). For women with multiple high-risk factors,
including a strong family history, prolonged use of the contraceptive pill, early
menarche, and nulliparity- just those groups that are most strongly urged to
have annual mammograms- the cumulative
risk of false positives increases to "as high as 100 percent" over a decade's
screening (16).
Overdiagnosis
Overdiagnosis and subsequent overtreatment are
among the major risks of mammography. The widespread and virtually unchallenged
acceptance of screening has resulted in a dramatic increase in the diagnosis
of ductal carcinoma-in-situ (DCIS), a pre-invasive cancer, with a current estimated
incidence of about 40,000 annually. DCIS is usually recognized as micro-calcifications
and generally treated by lumpectomy plus radiation or even mastectomy and chemotherapy
(17). However, some 80 percent of all DCIS never become invasive even if left
untreated (18). Furthermore, the breast cancer mortality from DCIS is the same- about
1 percent- both for women diagnosed and treated early and for those diagnosed
later following the development of invasive cancer (17). That early detection
of DCIS does not reduce mortality is further confirmed by the 13-year follow-up
results of the Canadian National Breast Cancer Screening Study (19). Nevertheless,
as recently stressed, "the public is much less informed about over-diagnosis
than false positive results. In a recent nationwide survey of women, 99 percent
of respondents were aware of the possibility of false positive results from mammography,
but only 6 percent were aware of either DCIS by name or the fact that mammography
could detect a form of 'cancer' that often doesn't
progress" (20).
Quality Control
In 1992 Congress passed the National Mammography
Standards Quality Assurance Act requiring the Food and Drug Administration (FDA)
to ensure that screening centers review their results and performance: collect
data on biopsy outcomes and match them with the original radiologist's interpretation
of the films (21). However, the centers do not release these data because the
Act does not require them to do so. It is essential that this information now
be made fully public so that concerns about the reliability of mammography can
be further evaluated. Activist breast cancer groups would most likely strongly
support, if not help to initiate, such overdue action by the FDA.
FAILURE TO
REDUCE BREAST CANCER MORTALITY
Despite the long-standing claims, the evidence
that routine mammography screening allows early detection and treatment of breast
cancer, thereby reducing
mortality, is at best highly questionable. In fact, "the overwhelming majority
of breast cancers are unaffected by early detection, either because they are
aggressive
or slow growing" (21). There is supportive evidence that the major variable predicting
survival is "biological determinism- a combination of the virulence of the individual
tumor plus the host's immune response," rather than just early detection (22).
Claims for the benefit of screening mammography in reducing breast cancer mortality
are based on eight international controlled trials involving about 500,000 women
(23). However, recent meta-analysis of these trials revealed that only two, based
on 66,000 postmenopausal women, were adequately randomized to allow statistically
valid conclusions (23). Based on these two trials, the authors
concluded that "there is no reliable evidence that screening decreases breast
cancer
mortality- not even a tendency towards an effect." Accordingly, the authors concluded
that there is no longer any justification for screening mammography; further
evidence for this conclusion will be detailed at the May 6, 2001, annual meeting
of the National Breast Cancer Coalition in Washington, D. C., and published in
the July report of the Nordic Cochrane Centre.
Even assuming that high quality
screening of a population of women between the ages of 50 and 69 would reduce
breast cancer mortality by up to 25 percent, yielding a reduced relative risk
of 0.75, the chances of any individual woman benefiting are remote (18). For
women in this age group, about 4 percent are likely to develop breast cancer
annually, about one in four of whom, or 1 percent overall, will die from this
disease. Thus, the 0.75 relative risk applies to this 1 percent, so 99.75 percent
of the women screened are unlikely to benefit.
THE UNITED STATES VERSUS OTHER
NATIONS
No nation other than the United States routinely screens premenopausal
women by mammography. In this context, it may be noted that the January 1997
National Institutes of Health Consensus Conference recommended against premenopausal
screening (24), a decision that the NCI, but not the ACS, accepted (4). However,
under pressure from Congress and the ACS, the NCI reversed its decision some
three months later in favor of premenopausal screening.
The U. S. overkill extends
to the standard practice of taking two or more mammograms per breast annually
in postmenopausal women. This contrasts with the more restrained European practice
of a single view every two to three years (4).
BREAST EXAMINATION IS A SAFE AND
EFFECTIVE ALTERNATIVE TO MAMMOGRAPHY
That most breast cancers are first recognized
by women themselves was admitted in 1985 by the ACS, an aggressive advocate of
routine mammography for
all women over the age of 40: "We must keep in mind the fact that at least 90
percent of the women who develop breast carcinoma discover the tumors
themselves" (25). Furthermore, as previously shown, "training increases reported
breast self-examination frequency, confidence, and the number of small tumors
found" (26).
A pooled analysis of several 1993 studies showed that women who
regularly performed BSE detected their cancers much earlier and with fewer
positives nodes and smaller tumors than women failing to examine
themselves (27); BSE would
also enhance earlier detection of missed or interval cancers, especially
in pre-menopausal women (28). There is a strong consensus that
the effectiveness of BSE critically
depends on careful training by skilled professionals, and that confidence
in BSE is enhanced with annual CBEs by an experienced professional
using structured
individual training (29). The tactile sensitivity of BSE can be increased
by the use of Mammacare techniques to enhance lump detection skills
(30, 31), and
by the use of FDA-approved and nonprescription thin and pliable lubricant-filled
sensor pads (32, 33).
In a joint U. S. and Chinese large-scale trial based
on 520 Chinese factories, women in half the factories were trained
in and practiced
BSE, while the other group of women served as controls (34). The five-year
follow up results reported no reduction in breast cancer mortality
in women in the BSE
group. However, these findings are of little, if any, significance in view
of the minimum of a 10-to 13-year period required before the efficacy
of mammography
is claimed to occur in premenopausal women (24), especially as some of the
trial's participants were in their thirties (28).
The critical
importance and reliability
of CBE has been strikingly confirmed by the recent Canadian National Breast
Cancer Screening Study (19). This reported the results of a unique
individually randomized
controlled trial on some 40,000 women, aged 50 to 59 on entry, followed by
record linkage for nine to 13 years, with active follow-up of cancer
patients for an
additional three years. Half the women performed monthly BSE, following instruction
by trained nurses, had annual CBEs (taking approximately ten minutes) by
trained nurses, and had annual mammograms, while the other half
practiced BSE and had
annual CBEs but no mammograms. It should be noted that the CBE performance
by trained nurses had been shown to be as good as, if not better
than, that of the
study surgeons (35), a finding of particular interest in view of the growing
perception among women that professional women are more sensitive than men
to women's health issues (36). The results of this study provide
clear evidence
on the reliability of CBE, in
association with BSE (19): "In women age 50- 59 years, the addition of annual
mammography screening to physical examination has no impact on breast cancer
mortality." In other words, the mammographic detection of nonpalpable cancers
failed to improve survival rates, as "the majority of the small cancers detected
by mammography represent pseudo-disease or overdiagnosis" (37); confirmation
of this explanation awaits a trial, a protocol of which is available, comparing
mammography alone with physical examination alone. It should further be noted
that the mammogram group had a three-fold increase in the number of false positives
compared with the CBE and BSE group, resulting in unnecessary biopsies.
The effectiveness
of CBE is further supported by the results of a new Japanese mass screening
study (38). Breast cancer mortality was compared in municipalities
with or without "high coverage" by CBE. The age-adjusted breast cancer mortality
between 1986- 1990 and 1991- 1995 was reduced by over 40 percent in "high coverage" municipalities,
in contrast to only 3 percent in controls. In spite of such evidence, the ACS
and radiologists persist in their dismissiveness of CBE and BSE, particularly
as "a substitute for screening practices that have a 'proven' benefit such as
mammograms" (33). The NCI no longer prints a BSE guide in its breast cancer booklet,
claiming that "no studies have clearly
shown a benefit of using BSE"; similarly, the ACS no longer distributes information
on BSE, such as shower-hanger cards.
There are immediate needs for a large-scale
crash program for training nurses in how to perform annual CBE and how
to teach BSE. This need is critical for underinsured and uninsured
low-socioeconomic and
ethnic women in the United States, and even more so for developing countries.
Once well trained, women of all social and cultural classes could perform
monthly BSE, at no cost or risk apart from false positives, which
decrease with increasing
practice, along with annual CBE screening. Clinics offering CBE and training
in BSE could be established nationwide, and eventually worldwide, in
a network of clinics, community hospitals, churches, synagogues,
and mosques. These clinics
could also act as a comprehensive source of reliable information on how
to reduce the risks of breast cancer, about which women still remain
largely uninformed
by the cancer establishment (2). Besides lifestyle and reproductive risk
factors, emphasis should be directed to the massive overprescription
of carcinogenic hormonal
drugs and the avoidable and involuntary exposures to petrochemical and
radionuclear carcinogens
in the totality of the environment (39- 41).
COSTS OF SCREENING
The dangers and
unreliability of mammography screening are compounded by its growing
and inflationary costs; Medicare and insurance average costs are
$70 and $125, respectively. Inadequate
Medicare reimbursement rates are now prompting fewer hospitals and
clinics to offer mammograms, and deterring young doctors from becoming
radiologists. Accordingly,
Senators Charles Schumer (D-NY) and Tom Harkin (D-IA) are introducing
legislation to raise Medicare reimbursement to $100 (42).
If all
U. S. premenopausal women,
about 20 million according to the Census Bureau, submitted to annual
mammograms, minimal annual costs would be $2.5 billion (4). These
costs would be increased
to $10 billion, about 5 percent of the $200 billion 2001 Medicare budget,
if all postmenopausal women were also screened annually, or about
14 percent of
the estimated Medicare spending on prescription drugs. Such costs will
further increase some fourfold if the industry, enthusiastically
supported by radiologists,
succeeds in its efforts to replace film machines, costing about $100,000,
with the latest high-tech digital machines, approved by the FDA
in November 2000,
costing about $400,000. Screening mammography thus poses major threats
to the financially strained Medicare system. Inflationary costs
apart, there is no evidence
of the greater effectiveness of digital than film mammography (43),
as confirmed by a study reported at the November 2000 annual meeting
of the Radiological Society
of North America (44). In fact, digital mammography is likely to result
in the increased diagnosis of DCIS.
The comparative cost of CBE
and mammography in the
1992 Canadian Breast Cancer Screening Study was reported to be 1 to
3 (45). However, this ratio ignores the high costs of capital items
including buildings, equipment,
and mobile vans, let alone the much greater hidden costs of unnecessary
biopsies, specialized staff training, and programs for quality
control and professional
accreditation (46). This ratio could be even more favorable for CBE
and BSE instruction if both were conducted by trained nurses. The
excessive costs of mammography
screening should be diverted away from industry to breast cancer prevention
and other women's health programs.
CONFLICTS OF INTEREST
The ACS
has close connections
to the mammography industry (39). Five radiologists have served as
ACS presidents, and in its every move, the ACS promotes the interests
of the major manufacturers
of mammogram machines and films, including Siemens, DuPont, General
Electric, Eastman Kodak, and Piker. The mammography industry also
conducts research for
the ACS and its grantees, serves on advisory boards, and donates considerable
funds. DuPont also: is a substantial backer of the ACS Breast Health
Awareness Program; sponsors television shows and other media productions
touting mammography;
produces advertising, promotional, and information literature for hospitals,
clinics, medical organizations, and doctors; produces educational films;
and, of course, lobbies Congress for legislation promoting availability
of mammography
services. In virtually all its important actions, the ACS has been
and remains strongly linked with the mammography industry, while
ignoring or attacking the
development of viable alternatives (39).
ACS promotion continues to lure women of all ages into mammography centers, leading them to
believe that mammography
is their best hope against breast cancer. A leading Massachusetts newspaper
featured a photograph of two women in their twenties in an ACS
advertisement that promised
early detection
results in a cure "nearly 100 percent of the time." An ACS communications director,
questioned by journalist Kate Dempsey, admitted in an article published by the
Massachusetts Women's Community's journal Cancer, "The ad isn't based on a study.
When you make an advertisement, you just say what you can to get women in the
door. You exaggerate a point. . . . Mammography today is a lucrative [and] highly
competitive business" (39).
NEEDED REFORMS
Mammography is a striking paradigm
of the capture of unsuspecting women by run-away powerful technological
and pharmaceutical global industries, with the complicity of the
cancer establishment, particularly
the ACS, and the rollover mainstream media. Promotion of the multibillion
dollar mammography screening industry has also become a diversionary
flag around which
legislators and women's product corporations can rally, protesting
how much they care about women, while studiously avoiding any reference
to avoidable risk factors
of breast cancer, let alone other cancers.
Screening mammography
should be phased out in favor of annual CBE and monthly BSE, as
an effective, safe, and low-cost
alternative, with diagnostic mammography available when so indicated.
Such action is all the more critical and overdue in view of the
still poorly recognized evidence
that screening mammography does not lead to decreased breast cancer
mortality (18, 21, 23).
Networks of CBE and BSE clinics, staffed
by trained nurses, should
be established internationally, including in developing nations.
These low-cost clinics would further empower women by providing
them with scientific evidence
on breast cancer risk factors and prevention, information of particular
importance in view of the continued high incidence of breast cancers,
with an estimated
192,200 new U. S. cases predicted for 2001 (47), exceeding the number
for any previous years. The multibillion dollar U. S. insurance
and Medicare costs of
mammography, besides those in other nations, should be diverted to
outreach and research on prevention of breast and other cancers
and on other women's health
programs.
Acknowledgments - The comments and advice of Dr. Cornelia
Baines and Maryann Napoli are gratefully acknowledged.
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CONTACT:
Samuel S. Epstein, M.D.,
Chairman
Cancer Prevention Coalition
2121 West Taylor Street, M/C 922
Chicago, IL 60612-7260
epstein@uic.edu
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