1. 30 May 2015 | itnonline.com | Imaging Technology News
medical director at Lynn Sage Comprehensive
Breast Center, Northwestern Memorial Hospital in
Chicago, discussed the main criticisms of screening
mammography.These include recommendations
by the United States Preventive ServicesTask Force
(USPSTF) and the Swiss Medical Board, as well as
concerns regarding overdiagnosis of breast cancer
and the survival benefit in women who have been
screened.
Mammography is only approximately 70 percent
sensitive for all breast types. For women with dense
breasts, it’s even more limited — closer to
50 percent.1
According to Friedewald, because of
these major differences in standard mammography,
the limited sensitivity and high recall rate, traditional
mammography has been highly criticized.
USPSTF Recommendations
The USPSTF was formed in 1984 as an independent
volunteer panel of 16 members, with a mission to
improve the health of the U.S. population. These
members specialized in prevention and primary care,
and targeted areas such as behavioral health, family
medicine, geriatrics, internal medicine, pediatrics,
OB/GYN and nursing. The task force made evidence-
based recommendations about clinical, preventive
services such as screening, counseling services and
preventive medicine.
In 1998, the Agency for Healthcare Research
and Quality (AHRQ) was authorized by Congress
to convene the task force and provide ongoing
scientific, administrative and dissemination support.
It continues to provide an annual report for Congress,
which includes critical evidence gathered in
research that relates to clinical preventive services,
and also recommends key areas that deserve
further examination.The result is a scorecard that
was released in 2009, which is currently in the
process of being updated.The new USPSTF set of
recommendations is anticipated to be released this
summer. In late April, USPSTF declined to expand
its recommendation on which women should
receive regular mammography screening, instead
issuing a draft of new breast screening guidelines
that parallel its 2009 findings. According to the U.S.
Preventive ServicesTask Force website, the task
force’s draft recommendations are designed for
women 40 and older who do not show any signs
or symptoms of breast cancer, who have not been
women’s health
Screening Controversy
B
reast cancer screening has been on the forefront with the issue of breast density
taking center stage. However, controversy surrounds the many contradicting
studies that currently dictate the standards for breast cancer screening.
Attherecent25thAnnualInterdisciplinaryBreastCenterConference(NCoBC),
Sarah M. Friedewald, M.D., division chief of breast and women’s imaging, and
Controversies
inBreast
Cancer
ScreeningA look into the controversial and confusing studies that currently
dictate the standards for breast cancer screening
By Melinda Taschetta-Millane

2. Imaging Technology News | itnonline.com | May 2015 31
previously diagnosed with breast cancer and who
are not at high-risk for breast cancer, meaning they
do not have a known genetic mutation or a history
of chest radiation at a young age.Women at high-
risk of breast cancer should consult their doctors
for individualized recommendations regarding
screening. It goes on to say that the task force
recognizes mammograms can help women in their
40s reduce the risk of dying from breast cancer.
Because the risk of developing breast cancer is
lower in women under 50, the potential benefit of
mammography for women under 50 is also smaller,
according to USPSTF.
As of April 20, 2015, the USPSTF screening
recommendations were proposed as follows. For a
complete definition of what these grades mean, see
Figure 1: A Definition of USPSTF Grades.
Women ages 50-74
The USPSTF recommends screening mammography
every two years for women ages 50 to 74 years.
B recommendation
Women ages 40-49
The decision to start screening
mammography in women before
age 50 should be an individual one.
Women who place a higher value
on the potential benefit than the
potential harms may choose to
beginscreeningbetweentheagesof
40 and 49 years. C recommendation
Women 75 and older
The current evidence is insufficient to assess
the balance of benefits and harms of screening
mammography in women 75 years and older.
I statement
In a rebuttal to these new proposed
recommendations, the American
College of Radiology (ACR) and Society
of Breast Imaging (SBI) have issued
a statement saying that adoption
of the proposed USPSTF breast
cancer screening recommendations
draft would result in thousands of
additional and unnecessary breast
cancer deaths each year.Thousands
more women would experience more
extensive and expensive treatments
than if their cancers were found early
by a regular mammogram. Adoption
of these USPSTF recommendations
could also strip millions of women
over 40 of private insurance coverage
with no copay for mammograms at
the time of their choosing previously
guaranteed by the Affordable Care
Act (ACA).
Friedewald explained that
according to the 2009 recommendations, it claimed
that the harm of the screening outweighed the
benefits, and there was psychological harm and
unnecessary imaging tests for women without
cancer, a significant inconvenience to the false positive
screening results, and an overdiagnosis of cancer.
“I’m going to tell you a little bit about the USPSTF,”
said Friedewald.“There were no oncologists,
radiologists or surgeons on the committee, none
of the members were involved in breast cancer
care, and their recommendations really were for
average-risk women, which I think gets lost in the
shuffle here. So we have a lot of women who are
at high risk, but a lot of people just latch on to
these recommendations and think that they are for
everybody.
“This review was based on data going back to
1963, rather than gathering new information,
so there wasn’t a big study that came out
that led to these new recommendations,”she
continued.“Their data did not incorporate
digital mammography. Interestingly, they were
commissioned by Congress to determine the
recommendations, but that was also the same
year that the Affordable Care Act was passed into
law. So there are some questions as to what the
motivations were of the USPSTF.”
To break this information down further, it’s
important to look at the recommendation for
screening given at age 50.“Age 50 is an arbitrary
threshold not supported by trials, and it was
historically chosen because it was a marker for
menopause,”said Friedewald, explaining there is a
concept of breast cancer being related to hormonal
status.“But again, there is no data to support that
screening should be given starting at age 50. In
fact, we have data showing that it really should
begin at age 40. We also did dispute the fact that
there was a 15 percent reduction in mortality of
women in their 40s, but they felt that the absolute
number of women benefitting was small because
of the incidence of cancer in that age group. There
are varied numbers of people in this age group
depending on the population at this time. So with
the baby boomers, there were a lot of women in
this age group; just because there may be a lower
incidence, there still may be an absolute large
number of women in this age group that would
benefit from screening.”
That’s starting at age 50, but what about
bi-annual screening? The difficulty with this, said
Friedewald, is that it decreases the opportunity to
identify cancers at an earlier stage. She suggested
that optimal screening time for women really
should be half the sojourn time. Sojourn time
is defined as the time between a tumor first
becoming mammographically visible and the
moment when the tumor was actually detected by
mammogram.2
“The longer the screening intervals make the
screening less effective. It’s important to recognize
what the sojourn time is,”stressed Friedewald,
explaining why screening every other year is
problematic.“Estimates for the sojourn time are
dependent on multiple factors, but the study done
at Mass General used a median doubling time of
130 days and we were able to calculate the mean
sojourn time for invasive breast cancers at 1.7
years. The USPSTF concluded that the harms could
be cut in half if there was a change to biannual
screening, but the benefit would be reduced
if greater than 24-month intervals between
screening. They obviously didn’t recognize the
issue of sojourn time.”
CNBSS Study
Another controversial study is the Canadian National
Breast Screening Study (CNBSS), where nearly
90,000 women participated. It was a prospective
randomized control trial for women aged 40
to 59, broken down into two groups: women
“Mammography is only approximately 70 percent
sensitive for all breast types. For women with dense
breasts, it’s even more limited — closer to 50 percent.”

3. 32 May 2015 | itnonline.com | Imaging Technology News
who had physical examinations plus screening
mammography, and women who had a physical
exam and usual care after the initial physical
examination without screening.The patients were
divided into two age groups: women in their 40s and
women in their 50s.These seven-year results were
published in 1992.
“Their conclusion was screening with yearly
mammography plus physical examination decreased
significantly more, with no negative small tumors
in the control group, no impact on the rate of death
of breast cancer up to seven years follow-up from
entry,”said Friedewald, stressing that a greater than
seven-year follow-up is needed because a statistically
significant number of women will need to die to
demonstrate a benefit in the group.“Seven years
is basically too short to show that there was no
statistically significant difference in mortality.”
A 25-year follow-up was conducted on patients
in this study, and their conclusion was the same:
It did not reduce the mortality of breast cancer
beyond that physical examination and usual
care, when screening for breast cancer is readily
available.
“Let’s dive a little bit deeper into the problems
with this study,”said Friedewald.“There was
poor randomization, all women had a physical
examination prior to participation, allocation was
not blinded and randomization was performed
by a study coordinator at each of the study’s
15 sites. I think what shows proof of this is there is
an excess of node-positive women in the screened
group, which was statistically significant, and
the survival in the control group was better than
expected.”She explained that this meant there
were healthier people in the control group, more
than anticipated, and there were more serious
cancers in the screened group. In addition, there
was contamination and non-compliance.
Friedewald went on to explain that the quality
of imaging was poor, the technologists weren’t
taught proper positioning and the radiologists
had no specific training, which left it open for
interpretation.“And then finally there was the
separation of the two age groups. The women
in their 40s really lacked the physical power,
there weren’t enough people in those groups to
show statistical significance,”she said.“There is
no biological significance between the two age
groups. For example, women who are age 49 are
not statistically different from women who are 52.”
Overdiagnosis
In a paper published in JAMA, Laura Esterman, M.D.,
discussed the difficulties of overdiagnosis, which
Friedewald summarized in her presentation, saying
that physicians, patients and the general public
must recognize overdiagnosis as common, and that
it occurs more frequently with cancer.3
“So what is overdiagnosis? The concept is that
many cancers detected by mammography are
not clinically significant and do not cause death
in patients,”said Friedewald.“When we’re talking
about overdiagnosis we’re usually referring to
ductal carcinoma in situ (DCIS). But it’s very difficult
to estimate overdiagnosis because at the time of
Figure 1:
A Definition of USPSTF Grades
Information courtesy of the The U.S. Preventive Services Task Force (USPSTF)
According to the USPSTF website, the USPSTF updated its definition of and suggestions for practice for the grade C
recommendation.This new definition applies to USPSTF recommendations voted on after July 2012. Describing the strength
of a recommendation is an important part of communicating its importance to clinicians and other users. Although most of
the grade definitions have evolved since the USPSTF first began, none has changed more noticeably than the definition of
a C recommendation, which has undergone three major revisions since 1998. Despite these revisions, the essence of the C
recommendation has remained consistent: At the population level, the balance of benefits and harms is very close, and the
magnitude of net benefit is small. Given this small net benefit, the USPSTF has either not made a recommendation“for or
against routinely”providing the service (1998), recommended“against routinely”providing the service (2007), or recommended
“selectively”providing the service (2012). Grade C recommendations are particularly sensitive to patient values and circumstances.
Determining whether or not the service should be offered or provided to an individual patient will typically require an informed
conversation between the clinician and patient.
For more information, www.uspreventiveservicestaskforce.org/Page/Name/grade-definitions
women’s health
Screening Controversy
Grade Definition Suggestions for Practice
A The USPSTF recommends the service.
There is high certainty that the net benefit
is substantial.
Offer or provide this service.
B The USPSTF recommends the service.
There is high certainty that the net
benefit is moderate or there is moderate
certainty that the net benefit is moderate
to substantial.
Offer or provide this service.
C The USPSTF recommends selectively
offering or providing this service to
individual patients based on professional
judgment and patient preferences. There
is at least moderate certainty that the net
benefit is small.
Offer or provide this service for selected
patients depending on individual
circumstances.
D The USPSTF recommends against the ser-
vice. There is moderate or high certainty
that the service has no net benefit or that
the harms outweigh the benefits.
Discourage the use of this service.
I
Statement
The USPSTF concludes that the current
evidence is insufficient to assess the
balance of benefits and harms of the service.
Evidence is lacking, of poor quality or
conflicting, and the balance of benefits
and harms cannot be determined.
Read the clinical considerations section
of USPSTF Recommendation Statement.
If the service is offered, patients should
understand the uncertainty about the
balance of benefits and harms.
diagnosis, you can’t tell whether it’s a problem
concerning a lesion or not. It really can only be
estimated by the excess of incidence of breast
cancer over a long period of time when you are
screened compared to those who were not.”
Many estimates wrongfully state an increased
incidence of cancer in the screening group
because they don’t have enough lead-time bias.
“Screening mammography detects cancers prior
to being clinically evident, but at the beginning
of the screening program prevalent cancers get
incorporated with the incident cancers because they

4. Imaging Technology News | itnonline.com | May 2015 33
are detected earlier, and by physical examination,”
said Friedewald.“There’s a false sense that there are
actually more cancers, but there is no change in the
state of depth. That’s really what the lead-time bias
is. So not only do they not account for the lead-time
bias, but there is also too short of a follow-up.”
It’s important to keep in mind that the incidence
of invasive breast cancer is decreasing over time
— about 1 percent per year, said Friedewald.“This
is likely due to environmental factors, medication,
increase in age, childbearing and the number of
children a woman has,”she explained.“It’s not clear
that all DCIS at some point will progress to this
invasive cancer, or whether it will just stay as DCIS.
So at the time of diagnosis we don’t have any way
of knowing which ones will be the ones that are
going to hurt the patient and which ones are not.”
Friedewald said the focus should be on the
understanding of molecular characteristics of DCIS
so physicians can better understand the behavior
of those cells and modify a treatment, rather than
not screen patients.
Swiss Medical Board Assessment
The Swiss Medical Board, an independent health
technology assessment board, prepared a review
of mammography screening which was released
in February 2014.4
This task force consisted of
medical ethicists, clinical radiologists, surgeons
and clinical pharmacologists. They published
their perspective in the New England Journal
of Medicine. Friedewald explained that their
conclusion recommended against screening
completely. They felt that the survival benefit may
not be related to screening, citing studies from
1963-1991 showing a 20 percent reduction in
mortality with screening mammography.
The Swiss Medical Board concluded that the
harms of screening mammography outweighed
the benefits. They based this conclusion, in part,
on a Canadian study that showed 22 percent
of cancers were “overdiagnosed,” and there
was no mortality decrease. They also cited that
in a survey of women’s perceptions, women
overestimate the value of mammography versus
its actual benefit.
Current U.S. Screening Recommendations
According to the American Cancer Society
(ACS), American College of Radiology (ACR)
and the American Congress of Obstetricians
and Gynecologists (ACOG), annual screening
mammography can begin at 40 as long as the
woman is in good health.
The ACS recommends that for early breast
cancer detection, mammograms are a substantial
benefit for women in their 40s, noting that
mammography will miss some cancers, and
sometimes can lead to follow-up, including
biopsies, that are not cancer.
“Women should be told about these benefits
and limitations, and mammograms for older
women should be based on the individual’s health
and other serious illnesses such as congestive
heart failure, end-stage renal disease, chronic
obstructive pulmonary disease and dementia,”
Friedewald said.“Age alone will not be the reason
to stop having a regular mammogram.” itn
References:
1. Bird, RE, Wallace TW,Yankaskas BC.“Analysis of cancers missed at
screening mammography.”Radiology 1992. 184:613-617.
2. Querci della Rovere, G, Warren R, Benson J.“Early Breast Cancer”
Second Edition, Taylor Francis Group, 2006.
3. Esserman, L. “Viewpoint: Overdiagnosis and Overtreatment in
Cancer: An Opportunity for Improvement.”JAMA Aug. 23, 2013.
Volume 210:8.
4. “Abolishing Mammography Screening Programs? A View from the
Swiss Medical Board.”New England Journal of Medicine. May 22,
2014.
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