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Men's estimates of prostate cancer risk and self-reported rates of screening

Jeanette E Ward, Ann-Maree Hughes, Geoffrey H L Hirst and Lorraine Winchester

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Abstract - Introduction - Methods - Results - Discussion - Acknowledgements - References - Authors' details

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Abstract

 Objective: To determine rates of prostate cancer screening and predictors of men's participation in this screening in the light of national recommendations against prostate cancer screening.
Design: Community-based study (computer-assisted telephone survey).
Setting: Central Sydney Area Health Service.
Participants: Randomly selected men aged 40-80 years.
Results: 340 men participated (65% response rate). While the true lifetime (0-74 years) risk of developing or dying from prostate cancer is reported to be one in 18 (6%) and one in 65 (1.5%), respectively, 37% of respondents thought that at least one in five men (20%) would develop prostate cancer before the age of 75 years and 11% that one in five (20%) would die from it. Twenty-two per cent of men aged 50 years or over had been screened for prostate cancer within the previous 12 months. Ever worrying about prostate cancer and bothersome urinary symptoms independently predicted the probability of screening within the previous year. Sociodemographic characteristics such as age, occupation and country of birth were not associated with screening.
Conclusions: Public health initiatives to discourage prostate cancer screening should focus particularly on men with bothersome urinary symptoms and those who worry about prostate cancer. Accurate information about the low risks of dying from prostate cancer needs to be communicated, and the speculative nature of current evidence in support of screening as a means of reducing this risk should be emphasised.

MJA 1997; 167: 250-253  

Introduction

 Despite repeated advice to the contrary, screening for prostate cancer is being requested by patients and conducted by doctors. Advice against screening has come from a policy statement for health professionals released in 1995 by the Australian Cancer Society,1 and a 1996 report of a multidisciplinary committee convened by the Australian Health Technology Advisory Committee on the basis that the evidence did not meet accepted criteria for benefits, risks and costs.2 In addition, the National Health and Medical Research Council (NHMRC) evidence-based guidelines for the management of men with uncomplicated lower urinary tract symptoms (LUTS)3 state that there is no evidence that prostate specific antigen (PSA) tests are required for men with uncomplicated LUTS as men with these symptoms are at no greater risk of prostate cancer than asymptomatic men.4

Data indicating that screening is occurring come from the Department of Veterans' Affairs,5 as well as surveys of urologists6 and general practitioners (unpublished data). In describing this "conundrum", Horner identified a pressing need for research to support educational programs for men, focusing on "strategies to combat uninformed patient demand".7 While the Australian Health Technology Advisory Committee guidelines advocate national action involving the NHMRC,2 the need for health services to intervene actively at a local level to discourage prostate cancer screening has also been recognised in New South Wales.8

In the absence of more recent data, we used the opportunity of a large population-based study about men's health to determine the prevalence and predictors of participation in screening for prostate cancer in the area defined by the Central Sydney Area Health Service.  

Methods

The study was approved by the Royal Prince Alfred Hospital Ethics Review Committee.  

Community sampling

 Two thousand names, addresses and telephone numbers within the 35 postcodes constituting the Central Sydney area were randomly selected from the Electronic White Pages.9 To maximise participation rates, each household received a one-page letter outlining the Men's Health Study and anticipating telephone contact, supported by a media release to further publicise the study. The initial sample size of 2000 was estimated to be sufficient to provide between 250-350 completed surveys given an estimated prevalence of 38%10 of eligible male respondents in contacted households and a conservative consent rate.  

Computer-assisted telephone interview survey

 A market research company with computer-assisted telephone interview facilities contacted all 2000 households between 26 November and 12 December 1996 on weekdays between 1500 and 2100. Where the first contact was unsuccessful, a further five attempts were made at different times and on different days. Men aged between 40 and 80 years residing in the household and fluent in English were eligible to participate. If there was more than one man in the household meeting these criteria, the one with the most recent birthday was asked to participate.

Due to the sensitive nature of the survey, all telephone interviewers were mature females with previous experience in conducting health-related surveys. A briefing session for interviewers was conducted to address potential difficulties with medical jargon, to ensure sensitivity towards the issues and to standardise the interviews.  

Survey instrument

 At the beginning of the interview, respondents were asked standard sociodemographic questions, as well as whether they had ever been diagnosed with a urological condition and questions modified from the International Prostate Symptom Score11 to assess the presence of and degree of "bother" attributable to urinary symptoms.

We then asked respondents five questions about prostate cancer.

1. "Have you ever worried that you might have prostate cancer?" Those answering "yes" were asked "For what reasons?".

2. "Have you had any test to detect prostate cancer in the last 12 months?" Those answering "yes" were asked to name the test(s).

3. "Have you heard of any tests for prostate cancer?"

4. "Out of 100 Australian men, how many or what percentage do you think will get prostate cancer before the age of 75?" If the respondent was unable to quantify his response, the interviewer was instructed to establish a range by saying "Would it be more or less than 1%? Less than 5%? Between 5% and 9%? More than 10% or more than 20%?" until an answer was given.

5. "Out of 100 Australian men, how many or what percentage do you think will die from prostate cancer before the age of 75?" If necessary, an answer to this question was prompted in the same way as Question 4. For Questions 4 and 5, interviewers were unaware of the correct answers. Questions 4 and 5 were modelled on previous research. 12  

Data analysis

 Data were analysed using SAS13 and Epi Info.14 We used chi-squared tests to examine associations between knowledge of prostate cancer screening tests and eight respondent characteristics: age (40-49, 50-59, 60-69, 70-80 years); country of birth (Australia v. other); socioeconomic status based on occupation (manager/ administrator and professional/para-professional combined v. all other categories [tradesperson/clerk/salesperson and personal service worker/plant and machine operator/driver and labourer]);15 education (up to and including Intermediate or School Certificate [Year 10] v. Leaving or Higher School Certificate [Year 11 or 12] and beyond); moderate or severe "bother" from urinary symptoms (a score equal to or greater than six from a possible range of 0-18); ever worrying about prostate cancer (yes v. no); estimate of risk of developing prostate cancer (correct or lower estimate v. overestimate); and estimate of risk of death from prostate cancer (correct or lower estimate v. overestimate). Jelfs et al. report a lifetime risk of developing prostate cancer of one in 18 (6%).16 We considered an estimate of 10% or greater to be an overestimate of incidence risk. Using the Jelfs data,16 we calculated the lifetime risk of dying of prostate cancer as one in 65 (1.5%). We considered an estimate of 5% or greater as an overestimate of mortality risk. For the sample of men 50 years and over, we used chi-squared tests to determine associations between the outcome variable -- having had either a prostate specific antigen test, a digital rectal examination, or both, within the previous 12 months -- and these eight variables as well as knowledge of prostate cancer tests. Logistic regression analysis was performed, using significant univariate variables and any plausible non-significant variable.  

Results

  

Response rate and characteristics of the sample

 Of 2000 randomly selected households, 1481 (74%) were ineligible. Of the remaining 519 households with an eligible male resident, 340 agreed (65% response rate). Men who refused were significantly older than those who participated (t27.49 = 4.19; P < 0.01). Compared with 1991 Census data12 (Box 1), the sample under-represented older men. No respondent indicated a past history of prostate cancer.  

Respondents' worry about prostate cancer, estimates of risk and knowledge of tests

 Ninety-nine men (29%) indicated they had ever worried about prostate cancer. The three most frequently cited reasons were: presence of urinary symptoms (36 men [11%]), age (26 men [8%]), and media publicity (24 men [7%]).

Of the sample, 216 men (63%) overestimated lifetime risk of developing prostate cancer (Box 2). Respondents were significantly more likely to overestimate the risk of death from prostate cancer than the risk of developing it (McNemar's test, 10.800; df = 1; P = 0.001). Ever having worried about prostate cancer was not associated with correctly estimating the risk of developing it or the risk of dying from it. Of the total sample, 237 (70%) and 228 (67%) required no prompting to estimate lifetime risk of developing or dying from prostate cancer, respectively.


 

One hundred and seventy-two men (51%) reported they had heard of one or more tests for prostate cancer. Respondents who had heard of any test were more likely to be managers or professionals than to have other occupations (chi-squared = 4.04; df = 1; P = 0.044) or were educated to Year 12 or beyond (chi-squared = 5.49; df = 1; P = 0.019). Knowledge of tests was unrelated to age, country of birth, perception of risk, "bother" from urinary symptoms or anxiety.  

Rates and predictors of prostate cancer screening within the previous 12 months

 Of the total sample, 52 men (15%) had had at least one prostate cancer screening test within the previous 12 months (Box 3). Almost all tests (97%) were reported by men 50 years or older, yielding an annual screening rate of 22% for this older group. For the subsample of 186 men aged 50 years or over, univariate analyses revealed only two variables to be significantly associated with having had a prostate cancer screening test within the past year: moderate or severe "bother" from urinary symptoms (chi-squared = 13.41; df = 1; P < 0.001), and "ever worrying" about prostate cancer (chi-squared = 18.38; df = 1; P < 0.001).


 

Knowledge of available tests and other sociodemographic variables were not associated with having had a test within the past year. However, as age was a potential confounder, it was included with the two significant univariate associations in the logistic regression analysis. After adjustment, "bother" and "anxiety" remained independent predictors (Box 4).


 

Discussion

 Just over one in five of the men in our study 50 years or over had had a prostate cancer screening test within the previous 12 months, a rate almost double that given in an earlier report of national claims data.5 Screening was significantly more likely among those who had ever worried about prostate cancer or were bothered by urinary symptoms. In contrast to research in other countries demonstrating that economic and ethnic factors influence participation in prostate cancer screening,17,18 our study showed no association between screening and men's occupation, education or country of birth.

As a priority for public campaigns, men who experience uncomplicated LUTS -- nocturia, frequency, dribbling, urgency, hesitancy or reduced stream -- in the absence of haematuria need to be reassured that there is no empirical evidence of a relationship between such symptoms and early prostate cancer.3 Men's anxiety about prostate cancer may also be explained, in part, by their overestimation of the actual risks of prostate cancer. More than a third of respondents thought that at least one in five men would develop prostate cancer before the age of 74 years, and 11% thought that one in five would actually die from this disease before that age. Reasons for consistent overestimation of risk remain speculative but might reflect extensive media coverage of prostate cancer, possibly fuelled by commercial interests, which increases men's anxiety, and, in turn, raises their perception of risk.19 In contrast, McCormick20 has argued that informed public participation in screening should be founded on clear messages about absolute risk, the evidence from rigorous randomised trials for reduction in risk, the costs and adverse outcomes. Our study is the first to quantify a considerable gap between men's perceptions of risk and the actual risk. When provided with impartial information on an individual basis about the risks and unknown benefits of prostate cancer screening, men are less inclined to have a screening test.21

Given our collective failure to convey accurate health risk information to the public about risks for other cancers,9 risk reduction22 or screening,23 a systematic approach to the development, implementation and evaluation of a public health initiative to discourage prostate cancer screening is required. The recent release of the guidelines for the management of uncomplicated LUTS in men3 provides a focus for such an initiative. Our study suggests that men who are anxious about prostate cancer or have bothersome urinary symptoms represent priority target groups for educational messages via general practice, men's service and recreation clubs, mass media and peak groups such as the Council of the Ageing and the Consumers' Health Forum.

Because of the limitations of our study, we also recommend that a dedicated survey about prostate cancer be conducted which examines in depth men's knowledge of indolent and aggressive cancer types, their health beliefs and attitudes towards early detection, their awareness of the speculative and controversial nature of screening, and their knowledge of treatment options and their effectiveness. Men's recall of the recommendations of their GP in either promoting or discouraging prostate cancer screening could also be ascertained. As female partners represent a key source of health information for men,24 a concurrent survey of partners of men in these age groups is also recommended.  

Acknowledgements

 The Men's Health Study was conducted for the NHMRC Working Party developing guidelines for the management of lower urinary tract symptoms in men with funds from the Commonwealth Department of Health and Family Services. We thank members of the Working Party for comments on survey protocols; the men who participated in the computer-assisted telephone interview and the Hunter Valley Research Foundation for diligent administration of the survey; Jo Williams and the Central Sydney Area Health Service Public Relations Unit for assisting with the media release; and Neil Donnelly for statistical advice.  

References
  1. Australian Cancer Society. Prostate cancer screening: guidelines for health professionals. Cancer Forum 1995; 19: 47-50.
  2. Australian Health Technology Advisory Committee. Prostate cancer screening. Canberra: AGPS, 1996.
  3. NHMRC clinical practice guidelines. The management of uncomplicated lower urinary tract symptoms in men. Canberra: AGPS, 1996.
  4. Catalona W, Ritchie J, Ahmann F, et al. Comparison of digital rectal examination and serum prostate specific antigen in the early detection of prostate cancer: results of a multicenter clinical trial of 6,630 men. J Urol 1994; 151: 1283-1290.
  5. Parkes A, Killer G. Prostate-specific antigen -- is it already being used as a screening test? Med J Aust 1994; 161: 722.
  6. Urological Society of Australasia. Prostate screening, a personal choice: surgeons. Media release, 27 August 1996.
  7. Horner D. Prostate cancer: a challenge for health promotion. Health Promot J Aust 1996; 6: 3-7.
  8. Cancer Expert Working Group. Cancer control NSW goals and targets. North Sydney: NSW Health, August 1995.
  9. Oz On Disc. Sydney: Read Only Memory Pty Ltd, May 1996.
  10. Rissel C, Winchester L, Hodge W, et al. Health outcome indicators for Central Sydney. Sydney: Needs Assessment & Health Outcomes Unit, Central Sydney Area Health Service, August 1996.
  11. Cockett A, Aso Y, Denis L, et al. Recommendations of the International Consensus Committee. In: Proceedings of the International Consultation on Benign Prostatic Hyperplasia (BPH). Paris: SCI, June 1991: 279-281 (ISBN 2-905744-11-1).
  12. Clover K, Redman S, Boyle K, et al. Community knowledge of cancer. Health Promot Int 1991; 6: 93-101.
  13. SAS [computer program], version 6. 3rd ed. Cary, NC: SAS Institute, 1990.
  14. Dean AG, Dean JA, Burton AH, Dicker RC. Epi Info, version 5: a word processing database, and statistics program for epidemiology on microcomputers. Stone Mountain, Ga: USD Inc, 1990.
  15. Australian Bureau of Statistics. Australian standard classification of occupations. 1st ed. Canberra: AGPS, 1992.
  16. Jelfs P, Coates M, Giles G, et al. Cancer in Australia 1989-1990 (with projections to 1995). Canberra: Australian Institute of Health and Welfare, 1996 (Cancer Series No. 5).
  17. Schwartz K, Kau T, Severson R, Demers R. Prostate-specific antigen in a community screening program. J Fam Pract 1995; 41: 163-168.
  18. Williams R, Boles M, Johnson R. Use of prostate-specific antigen for prostate cancer screening in primary care practices. Arch Fam Med 1995; 4: 311-315.
  19. Wasson J. Prostate cancer fears and facts. In: Proceedings of the National Men's Health Conference; 10-11 August 1995. Canberra: AGPS, 1996: 69-72.
  20. McCormick J. Medical hubris and the public health: the ethical dimension. J Clin Epidemiol 1996; 49: 619-621.
  21. Wolf A, Nasser J, Wolf A, Schorling J. The impact of informed consent on patient interest in prostate-specific antigen screening. Arch Intern Med 1996; 156: 1333-1336.
  22. Hancock L, Sanson-Fisher RW, Redman S, et al. Knowledge of cancer risk reduction practices in rural towns of NSW. Aust N Z J Public Health 1996; 20: 529-537.
  23. Cockburn J, Redman S, Hill D, Henry E. Public understanding of medical screening. J Med Screen 1995; 2: 224-227.
  24. Norcross W, Ramirez C, Palinkas L. The influence of women on the health care-seeking behaviour of men. J Fam Pract 1996; 43: 475-480.
(Received 24 Feb, accepted 22 May 1997)

Subsequently cited in Prostate-specific antigen testing in Australia and association with prostate cancer incidence in New South Wales by David P Smith and Bruce K Armstrong, Med J Aust 1998; 169: 17-20  

Authors' details

Central Sydney Area Health Service, Needs Assessment & Health Outcomes Unit, Sydney, NSW.
Jeanette E Ward, PhD, FAFPHM, Director;
Ann-Maree Hughes, BEd, GradDipAppSci(Nursing), Research Assistant;
Lorraine Winchester, BSocSc(Hons), Data Manager.

Taylor Medical Centre, Brisbane, QLD.
Geoffrey H L Hirst, MB BS, FRACS, Urologist.
Reprints: Associate Professor J E Ward, Central Sydney Area Health Service, Needs Assessment & Health Outcomes Unit, PO Box 374, Camperdown, NSW 2050.
E-mail: jward AT nah.rpa.cs.nsw.gov.au

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