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| Journal of the New Zealand Medical Association,
20-June-2003, Vol 116 No 1176
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Prostate cancer screening: knowledge, experiences and
attitudes of men aged 40–79 years
Bruce Arroll, Salil Pandit and Stephen Buetow
Prostate cancer is the most common cause of cancer-related
death in men (3.8%) behind lung cancer (6.1%) and bowel cancer
(4%).1 In terms of new cancers it is the most
commonly diagnosed, with 2439 cases reported in 1998. In the same year 1247 new
cases of large-bowel cancer and 967 cases of lung cancer were reported. The
number of deaths from prostate cancer was 502. This was in the absence of
agreement about treatment for clinically localised prostate cancer. A USA study
of urologists and radiation oncologists found that urologists would choose
radical prostatectomy as their treatment option. Meanwhile, 72% of the
oncologists considered surgery and external beam radiotherapy to be equivalent
treatments.2
Some observational studies show benefit from diagnosing
prostate cancer early. However, this does not, in itself, justify
screening.3 Randomized controlled trials are
required to assess screening because diagnostic tests in low prevalence settings
yield large numbers of false-positive results, each of which requires invasive
investigation.4 The harms from surgical
treatment are well documented. In one study 8.4% of men experienced incontinence
and 41.9% erectile dysfunction after radical prostatectomy for clinically
localised prostate cancer.5 Moreover, although
one published trial claims benefit from screening for prostate
cancer,6 no published randomized controlled
trials have yet found a mortality benefit for screening. In the absence of
sufficient evidence to screen, the Cancer Society of New Zealand’s
recommendation of not screening for prostate cancer should
stand.7 A New Zealand editorial noted that
different USA institutions had different recommendations for screening for
prostate cancer.8 It further commented that two
thirds of the men undergoing an ultrasound and biopsy of the prostate will not
have the disease and many will die with their prostate cancer, not of it. The
purpose of this study was to explore the knowledge, experiences and attitudes of
men aged 40–79 years regarding screening for prostate cancer.
MethodsParticipants were randomly
selected from the Auckland 2000 telephone directory and phoned in the summer of
2000/2001 or 2001/2002. The caller asked if any men present were aged between 40
and 79. If more than one were present, the person whose birthday was first in
the calendar year was chosen for the interview. He had the study explained to
him and, on giving verbal consent, was administered a structured interview. It
comprised 38 questions on knowledge, experiences and attitudes concerning issues
around prostate cancer. The questions were taken from other studies and
generated by the authors to answer relevant research questions. This study had
received ethical approval from the Auckland Ethics Committee. Results were
analysed using descriptive statistics and chi-square tests, performed on SPSS
v11.
ResultsThe response rate was 77% (120/156).
Where the denominator does not add up to 120 in the following results, this is
due to missing responses.
Table 1 shows the demographic characteristics of the
group.
Table 1. Demographics of study participants (n =
120)
Table 2 shows their knowledge of prostate cancer. Table 3
shows experiences and Table 4 documents attitudes.
Table 2. Knowledge of prostate cancer and screening
among study participants
*percentage of
responses
Table 3. Experiences regarding prostate cancer and
screening among study participants
DRE = digital rectal examination; PSA = prostate
specific antigen test; *responses rather than respondents
Table 4. Attitudes to prostate cancer and screening
among study participants
Ownership of health insurance was associated with having
both a prostate specific antigen (PSA) test and a digital rectal examination
(DRE), p = 0.020. Ownership of health insurance was more likely to be associated
with concern about getting prostate cancer (p <0.0001) and with having ever
been offered a test for prostate cancer (p <0.0001). A history of tertiary
education was associated with having ever been offered a test for prostate
cancer (p <0.001). Marginally non-significant was an association between an
annual gross income of $50 000 or more and concern about getting prostate cancer
(p = 0.059 one-sided).
DiscussionOf the men interviewed, 94%
(103/110) said that having routine health examinations was important and 81%
(91/113) stated that screening asymptomatic men for prostate cancer was
necessary. Fifty two per cent (60/116) of respondents indicated that the Cancer
Society recommends routine screening; only 2% knew that it does not recommend
screening for prostate cancer. Fifty five per cent (60/110) had been offered a
test for prostate cancer. Seventy five per cent of those offered the test
(45/60) reported that their doctor encouraged them to have a prostate-cancer
screening test despite the fact that the Cancer Society does not recommend this.
This suggests a need to inform doctors regarding screening practice. All but one
of the men who reported an offer of prostate cancer screening accepted it. Forty
four per cent of them (26/59) recalled no discussion with their doctor about the
advantages and disadvantages of having the test. This is a matter of concern
given the high proportion of men who believe that screening for prostate cancer
is worthwhile, and the high morbidity from surgery. However, most were satisfied
with the information they received about the benefits and harms of screening.
Ownership of health insurance increased the likelihood of having a DRE and PSA
test. Having a digital examination probably represents more thorough practice
(although not recommended for screening, it is recommended when looking for
clinically presenting prostate cancer) suggesting that the inverse care law
applies to those with health insurance; they were more concerned about getting
prostate cancer and more likely to be offered a screening test for this
disease.9
The strength of this study was that it involved a random
selection of men in the Auckland telephone directory. However, this source
favours the 97% of households with telephones in the Auckland urban
area10 and may therefore have missed some men
with the lowest incomes. Our sample comprised mainly New Zealand European men
(89% compared with 67% in the Auckland urban area and 80% in all of New
Zealand).10 Forty four per cent (52/117) of the
participants had a tertiary qualification; the expected percentage in the
Auckland urban area for men aged at least 15 is 36%. The response rate of 77%
may not be a true reflection of the actual response rate. The interviewer had a
concern that, in order to terminate the call, the person answering the telephone
might have used the excuse that no one in the defined age group was at home.
Reports of past screening behaviour and, in particular, what the doctor did
indicate only what participants could recall rather than necessarily what took
place.
In telephone interviews with men in Western
Australia11 and New
Mexico,12 56% and 48% respectively said that
they had been tested for prostate cancer. These statistics are similar to the
55% (60/110) offered a test in this study. Another study, conducted in New South
Wales, Australia, found that 44% had ever been screened for prostate
cancer.13 Ninety per cent of the New Mexico men
stated that prostate cancer screening was important compared with 81% (91/113)
in our study.
In the Western Australian study, almost two in every five of
the men who reported testing for prostate cancer said they received minimal
pre-test counselling or written information.11
In a USA study of men aged 45 to 70 years with no history of prostate cancer and
presenting to a university-based family medicine clinic most could not identify
the principal advantages and disadvantages of PSA
screening.14
An Australian survey found that 68% of general practitioners
considered a combination of DRE and PSA effective for prostate cancer
screening.15 A New Zealand survey found that
40% of general practitioners believed that all men aged 50 years or over should
be screened using DRE, PSA or both.16 However,
regardless of their beliefs in these tests, over 80% of these doctors screened
at least some of these patients with these tests. A study in the USA likewise
found that most family physicians screened for prostate cancer using a PSA test
in men older than 50 years.2 Another study of
primary care physicians in Missouri found that the majority believed that PSA
testing for prostate cancer was a useful
procedure.17 These findings suggest that
misconceptions about prostate cancer screening exist, and that they are an issue
in a number of countries. There are implications for both doctors and
patients.
Three in every five men (72/120) in our study reported
concern about getting prostate cancer. When diagnosed with prostate cancer a
high proportion of men are asymptomatic.18
Other men might not be sure whether they have symptoms because some are not well
defined. It is understandable, therefore, that patients and doctors should feel
a need to screen for the disease. However, our findings indicate that many men
and their doctors are unaware of the current evidence on screening for prostate
cancer. Men with positive tests are likely to be exposed to potentially harmful
and costly diagnostic and therapeutic interventions without knowing whether or
not treatment for screen-detected prostate cancer is effective. It is difficult
for groups such as the Cancer Society to get their message across to the public
unless scientific evidence informs the media publicity surrounding prostate
cancer in high-profile men. In our study, media sources accounted for 38%
(56/148) of the responses describing where participants learnt about treatment.
We would suggest a campaign to alert the public to the fact that it is unknown
whether treatment for screen-detected prostate cancer is effective and that
individuals should discuss this issue with their doctor. Our findings suggest
that doctors need appropriate information to deal with such questions. It should
include the complications of diagnostic procedures and treatment.
Author information:
Bruce Arroll, Associate Professor; Salil Pandit, Medical Student; Stephen
Buetow, Senior Research Fellow, Department of General Practice and Primary
Health Care, University of Auckland, Auckland
Acknowledgements: We
thank the Health Research Council for funding the summer studentship for Salil
Pandit.
Correspondence:
Associate Professor Bruce Arroll, Department of General Practice and Primary
Health Care, University of Auckland, Private Bag 92019, Auckland. Fax: (09) 373
7006; email: b.arroll@auckland.ac.nz
References:
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