Context Public health officials, physicians, and disease advocacy groups have
worked hard to educate individuals living in the United States about the importance
of cancer screening.
Objective To determine the public's enthusiasm for early cancer detection.
Design, Setting, and Participants Survey using a national telephone interview of adults selected by random
digit dialing, conducted from December 2001 through July 2002. Five hundred
individuals participated (women aged ≥40 years and men aged ≥50 years;
without a history of cancer).
Main Outcome Measures Responses to a survey with 5 modules: a general screening module (eg,
value of early detection, total-body computed tomography); and 4 screening
test modules: Papanicolaou test; mammography; prostate-specific antigen (PSA)
test; and sigmoidoscopy or colonoscopy.
Results Most adults (87%) believe routine cancer screening is almost always
a good idea and that finding cancer early saves lives (74% said most or all
the time). Less than one third believe that there will be a time when they
will stop undergoing routine screening. A substantial proportion believe that
an 80-year-old who chose not to be tested was irresponsible: ranging from
41% with regard to mammography to 32% for colonoscopy. Thirty-eight percent
of respondents had experienced at least 1 false-positive screening test; more
than 40% of these individuals characterized that experience as "very scary"
or the "scariest time of my life." Yet, looking back, 98% were glad they had
had the initial screening test. Most had a strong desire to know about the
presence of cancer regardless of its implications: two thirds said they would
want to be tested for cancer even if nothing could be done; and 56% said they
would want to be tested for what is sometimes termed pseudodisease (cancers growing so slowly that they would never cause problems during
the persons lifetime even if untreated). Seventy-three percent of respondents
would prefer to receive a total-body computed tomographic scan instead of
receiving $1000 in cash.
Conclusions The public is enthusiastic about cancer screening. This commitment is
not dampened by false-positive test results or the possibility that testing
could lead to unnecessary treatment. This enthusiasm creates an environment
ripe for the premature diffusion of technologies such as total-body computed
tomographic scanning, placing the public at risk of overtesting and overtreatment.
There is a growing recognition among medical professionals that cancer
screening is a double-edged sword. While some individuals may benefit from
early detection, others may only be diagnosed and treated for cancer unnecessarily.1,2 In recent years, the public has been
exposed to expert debate about many of the most basic assumptions of screening:
some scientists have challenged the utility of mammography for women younger
than age 50 years3-5 or
even for women at any age6,7;
questions have been raised about how often to be screened for cervical cancer8,9; and whether to be screened at all
for prostate8,9 or lung cancer.10 Emerging from these debates is a growing consensus
that to make good decisions about screening, the public needs access to balanced
information about its potential benefits and harms.11,12
But the public has long received a different message. Public health
officials, physicians, and disease advocacy groups have worked hard over a
number of years to persuade individuals living in the United States about
the importance of cancer screening. It is practically impossible to read a
major newspaper or popular magazine, watch television, ride public transportation,
visit the beauty parlor,13 or even lick a stamp14 without seeing a public service announcement promoting
some form of cancer screening. Most recently, aggressive direct to consumer
advertising is bringing a variety of new advanced, but unproven screening
tests including brain magnetic resonance imaging, lung and total-body computed
tomographic (CT) screening,15 and genetic testing
for "cancer genes" to the public.16
To understand the issues facing those who hope to bring balanced information
to the public, we conducted a national telephone survey during 2001 and 2002
to learn about adults' experience with a broad array of screening tests. Specifically,
we explored general beliefs about early detection, personal commitment to
screening, screening as an obligation, attitudes toward false-positive results,
and desire for total-body CT scanning, a new and potentially comprehensive
Our goal was to interview a nationally representative sample of adults
for whom screening for cancer was relevant. Because our focus was on screening,
we specifically targeted a screen-eligible population. Thus, we excluded individuals
with a history of cancer because a prior cancer diagnosis may change how one
thinks about screening and early detection. We further restricted our sample
to women aged 40 years or older and to men aged 50 years or older because
it is at these ages that most cancer screening is recommended (a notable exception
being Papanicolaou testing). This project was approved by the institutional
review boards at Dartmouth Medical School, Hanover, NH, and at the University
of Massachusetts, Boston.
We used random digit dialing to obtain a national probability sample
of households in the continental United States with telephone service. Figure 1 details the steps of our sampling
procedure. The process began with the generation of a random list of 4000
US telephone numbers for the goal of 500 completed interviews. From this list,
1702 working residential telephone numbers were identified. Interviewers successfully
completed a 3-minute "screening" interview with an English-speaking adult
at 1208 of the residences to identify individuals meeting study criteria.
At least one eligible adult resided in 697 of the households (if ≥1 eligible
adult was identified, a computer selected a respondent so that each eligible
person had an equal chance of being selected). A total of 500 individuals
completed the interview.
There is some debate in the survey research literature about how best
to calculate a response rate in this setting. The specific question is whether
to account for residences that could not be screened. To maximize transparency
of this issue, the American Association of Public Opinion Research17 suggests calculating 2 response rates using 2 different
denominators. The simplest approach (commonly seen in the literature) is to
ignore unscreened residences and use known eligible households as the denominator.
In our case, 500 responses were obtained from 697 eligible households—a
response rate of 72% among individuals known to be eligible. However, there
are almost certainly some eligible households among those not screened. The
second approach attempts to account for this by increasing the denominator
to include the estimated number of eligible households among unscreened households.
This estimate takes the proportion eligible among those households screened
(in our case, 697/1208 = 0.58) as the best estimate of the proportion eligible
among those households not screened. Thus in our case, among the 494 households
not screened, 287 (0.58 × 494) would be expected to be eligible. Using
this approach, we obtained 500 responses from an estimated 984 (697 + 287)
eligible households—providing responses from 51% of those estimated
to be eligible (N = 500).
Development. To learn how the public thinks
about screening, we conducted 2 focus groups with adults aged 40 years or
older to discuss cancer screening tests in general, experiences with specific
tests, and perceptions of the pros and cons of such testing. The focus group
and all subsequent survey development was done in collaboration with experts
at the Center for Survey Research, a professional survey research firm affiliated
with the University of Massachusetts. A draft survey instrument was developed
based on the results of the focus groups. Experienced interviewers then conducted
10 cognitive interviews to ensure that the questions were understood and that
the answers were meaningful. After revising the draft based on this feedback,
17 eligible adults identified by random digit dialing completed the survey;
these interviews were audiotaped and then coded to identify questions that
were difficult for interviewers to read or for respondents to answer. Final
revisions were made to the survey based on the pretest results.
Instrument. The survey consisted of a general
screening module (general questions about the value of early detection, worry
about cancer, and interest in total-body CT screening) and 4 modules about
common screening tests (mammography, Papanicolaou smear, prostate-specific
antigen [PSA] testing, and sigmoidoscopy or colonoscopy). The screening test
modules contained a parallel series of questions about the value of the test,
testing preferences (eg, frequency, starting and stopping age, current behavior),
experience with abnormal test results, understanding of screening controversies
or uncertainties and risk perceptions about the corresponding cancer. All
respondents received the general screening module and the sigmoidoscopy or
colonoscopy module; women also received the mammography and Papanicolaou test
modules, while men received the PSA module.
Administration. From December 2001 through
July 2002, interviews were conducted by professional interviewers from the
University of Massachusetts Center for Survey Research. All interviewers received
special training on the purposes and procedures of this particular study;
all underwent routine monitoring for quality control and feedback from a supervisor.
The interviews took an average of 20 minutes (range, 10-54 minutes). Answers
to the questions were directly entered into the computer-assisted telephone
interviewing system by the interviewer.
Analysis. We created weights to account for
differential probability of selection into our sample. An individual's probability
of selection was a function of the number of residential voice telephone lines
(ie, more phone lines, higher probability of selection) and the number of
eligible adults at the residence (ie, more eligible adults, lower probability
Survey researchers sometimes create a second set of weights to force
the sample proportions for selected demographic characteristics to match those
in the population. Theoretically such poststratification weights reduce bias
resulting from differences in response rates among demographic subgroups.
The technique is controversial, however, because it requires a substantial
assumption that nonrespondents would answer questions similarly to respondents.
Thus, if Native American males who did not graduate from high school were
underrepresented in the sample, the responses of these few individuals would
be weighted upward to represent the US population proportion of this subgroup.
Ironically, the more this kind of weighting has the potential to influence
the results (ie, when the sample looks least like the target population),
the more heroic the assumption.
Because the distribution of most demographic characteristics in our
sample closely approximated those in the 2000 US Census (Table 1), poststratification weighting is unlikely to influence
our results. Nevertheless, because the lowest education and oldest age groups
were underrepresented, we created poststratification weights to match the
US Census distribution on age, sex, race, Hispanic origin, educational attainment,
and region.18 Analyses using these weights
yielded results nearly identical (ie, ± 1%-2%) to those using only
the probability weights. For simplicity, and to avoid the assumptions inherent
in poststratification weighting, we present results using only the probability
weights. All analyses were performed using STATA statistical software (Version
7; College Station, Tex).
Desire for Early Detection
Most adults (87%) living in the United States believe routine cancer
screening is "almost always a good idea." Seventy-four percent believe that
finding cancer early saves lives "most" or "all of the time" (Table 2). Fifty-three percent believe screening usually reduces
the amount of treatment needed when cancer is found. But enthusiasm for screening
also reflects a desire to know about the presence of cancer—regardless
of its implications. Two thirds of individuals would want to be tested for
a cancer even if nothing could be done. Fifty-six percent would want to be
tested for what is sometimes called pseudodisease,
cancers so slow growing that even untreated would never cause problems during
the person's lifetime. Thirty-five percent believed they had had too few cancer
screening tests in the past (64% thought they had had "about the right number").
Virtually no one interviewed (2%) thought they had had "too many" cancer screening
Personal Commitment to Screening
We found that most adults say they have had cancer screening tests:
99% of US women aged 40 years or older reported having a Papanicolaou test
and having 89% mammography; 71% of men aged 50 years or older had a PSA test;
and 46% of the men and women in these age groups had a sigmoidoscopy or colonoscopy
(our findings closely reflect those from the 2001 Behavioral Risk Factor Surveillance
Survey19 whose corresponding numbers were 96%,
88%, 75%, and 48%, respectively). We also found that most women who had been
screened with a Papanicolaou test or mammography and most men who had been
screened with a PSA plan to undergo at least annual testing (Table 3).
To further gauge how personally committed individuals are to screening,
we asked those who were currently being screened how they would respond if
their physician told them to be screened less often. Fifty-eight percent of
women said they would overrule their physician if he or she suggested less
frequent Papanicolaou tests. Seventy-seven percent of men would continue to
undergo prostate screening and 74% of men and women would continue with colon
cancer screening (colonoscopy or sigmoidoscopy) even if their physician recommended
against testing. Few individuals thought there would ever be a time when they
would stop having routine screening tests; ranging from a high of 35% saying
they would ever stop having Papanicoloau tests to a low of 21% for stopping
mammography. In addition, if cost was not a concern, some would like to be
screened as frequently as every 6 months: 4% for colonoscopy or sigmoidoscopy,
13% for Papanicoloau test, 16% for mammography, and 19% for PSA test.
Screening as an Obligation
To learn whether the public views screening as an obligation (eg, the
right thing to do, or something individuals owe to their loved ones), we asked
respondents to judge whether a person in average health would be "irresponsible"
if he or she did not have screening (Figure
2). When asked about a 55-year-old person in average health, responses
ranged from 79% (rating forgoing Papanicoloau tests as irresponsible) to 54%
(for colonoscopy). A substantial proportion also believed that an 80-year-old
who chose not to be tested was irresponsible: ranging from 41% for mammography
to 32% for colonoscopy.
Impact of False-Positive Results
Overall, 38% of men and women in our sample had had at least 1 false-positive
screening result that required further testing (11% for PSA, 30% for Papanicoloau,
and 35% for mammography). Many of these individuals underwent invasive follow-up
procedures (Table 4). While most
individuals found out they did not have cancer within 2 weeks, 25% of women
with abnormal Papanicoloaou test results, 13% with abnormal mammograms, and
25% of men with false-positive PSA test results waited more than 1 month for
this information. Many individuals characterized this time as either "very
scary" or the "scariest time" of their lives (43% for Papanicoloau test, 37%
for mammography, and 58% for PSA test). Yet, looking back, 98% were glad they
had had the initial screening test.
Finally, to gauge general enthusiasm for screening, we examined the
public's interest in total-body CT scanning, a relatively new technology now
aggressively marketed to consumers. We first described a total-body CT as
a "3-D look inside your body using a CT scanner. A CT scan gives a very detailed
picture of your lungs, liver, heart, and other internal organs, as well as
bones and arteries. A total body scan can find many diseases like cancer before
they can be found by routine check-ups. The body scan is quick and painless."
After hearing this description, 86% said they wanted to have a free total-body
CT. To learn about the strength of desire for CT, we asked those individuals
who chose a free CT whether they would prefer a total-body CT scan or receiving
$1000 in cash. Eighty-five percent would choose the total-body CT scan (ie,
73% of the entire sample). Only 27% thought there might be any downside to
having a total-body scan (mostly discomfort during the procedure or anxiety);
14% mentioned concern for false-positive results, and 3% mentioned the downside
of unnecessary subsequent testing.
Most people in the United States are firmly committed to cancer screening.
Most individuals would overrule a physician who recommended against cancer
screening and could not imagine a time they would stop being tested. This
enthusiasm is not dampened by false-positive test results. While nearly half
the respondents who had experienced a false-positive result described the
episode as extremely scary, virtually all were glad they had had the original
Because it is a new and highly visible technology,15 we
specifically asked respondents about total-body CT screening. There are no
data to support the benefit (or even safety) of total-body CT screening, and
it is not endorsed by any professional medical organization.20 In
fact, total-body CT screening is actually discouraged by the American College
of Radiology and the American Association of Physicists in Medicine.21,22 Nevertheless, total-body CT scans
are directly and aggressively marketed to consumers. While there have been
a number of media reports about total-body CT,23-25 our
study is the first to systematically document the substantial public interest:
almost three quarters would choose such testing instead of receiving $1000
Our findings should be interpreted in light of several potential limitations.
First, since we used the telephone to select our respondents, the 5% of adults
living in households without telephone service26 are
not represented. Next, while our response rate was good—72% among individuals
known to be eligible and 51% among those estimated to be eligible—systematic
bias between respondents and nonrespondents is still possible. This concern
is lessened by the fact that our sample's demographics and screening rates
closely approximated official US Census statistics. Although the elderly and
persons with less formal education were underrepresented in our sample, stratified
analyses demonstrated that the beliefs examined did not differ importantly
from these characteristics. In addition, our findings about false-positive
PSA test results are based on only 10 men and should be interpreted cautiously.
Our findings are also limited because they cannot tell us exactly why
people living in the United States are so enthusiastic about screening. Our
data do, however, argue against one important possibility—that enthusiasm
stems from an exaggerated sense of cancer risk. We asked a variety of questions
to understand cancer risk perceptions and found no evidence of a widespread
overestimation of cancer risk. Instead we found that most individuals believe
they are at average or lower risk for each of the cancers considered, report
that they worry "a little" or "not at all" about getting cancer, and recognize
that cancer is typically not a rapidly fatal disease (data not shown).
Our work suggests that screening is not seen as a choice but as an obligation.
The idea that "you owe it to your children to be screened" and that it "would
be selfish" to forgo screening was expressed repeatedly in our focus groups.
This sentiment was borne out in the survey: two thirds, for example, believed
that a 55-year-old person who did not have routine screening was "irresponsible."
While the sense of obligation may, in part, stem from the intuitive appeal
of early detection (ie, everyone knows that "an ounce of prevention is worth
a pound of cure"), other factors are at work.
Health care marketing has created an environment in which screening
is portrayed as the safest course of action. Screening has long been marketed
as the preeminent weapon in the war on cancer.27 In
the name of improved population health, many well-meaning public health agencies
and disease advocacy groups use powerful messages to persuade individuals
to undergo screening with slogans like "take the test not the chance" or "don't
be a victim" or by the use of fear- and guilt-inducing images (eg, a picture
of the young children who lost an unscreened parent to cancer). Other efforts
to promote screening may be more self-interested. For example, an increasing
number of independent total-body CT scan centers market themselves directly
to the public with slogans like "new technology that could save your life";
these advertisements are often accompanied by personal anecdotes from individuals
who believe their lives were saved by the early diagnosis of an unsuspected
tumor. Regardless of the source of the message, the net effect is the same:
screening is always seen as the right thing to do.
Ironically, even what physicians see as the important harms of screening—false-positive
results and detection of pseudodisease—reinforce the apparent case for
screening. Virtually everyone who had a false-positive test result in our
survey was glad they had been tested and intended to be tested again. Apparently,
the relief experienced when the confirmatory test result comes back negative
overwhelms the substantial fear that came before. Even pseudodisease—often
taken to be the most important harm of screening because it results in the
unnecessary diagnosis and treatment of cancer—may reinforce enthusiasm
for screening: more people appear to have cancer (prevalence increases because
"occult" cancers are detected) and prognosis improves (due to lead time and
Some clinicians will see our results as welcome evidence of the success
of public health campaigns for widely recommended cancer screening tests.
Others will have quite a different take. They will see disturbing evidence
that these same campaigns have communicated a misleadingly simple and 1-sided
message—a message that discourages meaningful discussions about the
use of these tests in settings when the recommendations are less clear (eg,
screening at younger ages, at advanced age, or for individuals with multiple
However, we would hope that everyone can agree that these messages have
an undesirable adverse effect: a public that is primed to believe there is
value in having any test that is marketed as being able to find early cancer.
In the case of unproven tests such as total-body CT, excessive enthusiasm
makes it extremely easy for exaggerated marketing tactics to succeed. Consequently,
some have suggested that the government replicate what it has done with pharmaceutical
advertising and regulate the direct-to-consumer advertising of unproven tests,30 requiring that the advertisements are factually true
and provide balanced information about benefit and harm.31
But there are limits to what physicians should expect from governmental
intervention. The public's enthusiasm for cancer screening and resistance
to do less stems in large part from messages the medical establishment itself
has promulgated. Unfortunately, these messages have helped create an environment
that hinders discourse on the prudent use of existing tests and is ripe for
the premature diffusion of new ones. The challenge now is to balance messages
and reduce the public's risk for overtesting and overtreatment.
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Not Available 21 CFR §202.1.