Volk RJ, Cantor SB, Spann SJ, et al.: Preferences of husbands and wives for prostate cancer screening.

Predictors of interest in prostate-specific antigen screening and the impact of informed consent: what should we tell our patients?

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Volk RJ, Cantor SB, Spann SJ, et al.: Preferences of husbands and wives for prostate cancer screening. Arch Fam Med 1997;6:72-76.

Reviewed by

Henry Barry, MD, MS

Clinical question

When given the same information, do husbands and wives agree about being screened for prostate cancer?

Background

Whether to screen for prostate cancer is among the most controversial issues confronting family physicians. The issue is of sufficient uncertainty that many recommend obtaining informed consent (1,2), which has been shown to reduce the desire for screening and aggressive therapy. Patient preferences are therefore a major consideration in the decision to screen. In a previous cost-effectiveness analysis, the authors reported that screening for prostate cancer reduced a patient's quality-adjusted life expectancy by 8 months.(3) Their sensitivity analysis, in which a variety of values for patient preferences were entered into the model, showed that the screening decision was dependent on the quality of life (or utility) patients associate with different complications. This paper addresses the outcomes when both husbands' and wives' perspectives are considered.

Population studied

The authors studied 10 consecutive men and their wives presenting to a university-based family medicine clinic. The men were healthy 44 to 68 year olds.

Study design and validity

Cost-effectiveness analysis is a powerful method to evaluate the outcomes of decisions made under conditions of uncertainty. Several methods are used to estimate patient preferences for quality of life, also called "utilities": standard gamble, time trade-off, visual analog scales, and multi-attribute scales. The most valid method, standard gamble, is conceptually difficult for patients and physicians. The time trade-off method is more easily understood. In this study, the authors separated the couples and used the time trade-off method to obtain utilities for complications of prostate cancer treatment. They used these utilities to recalculate the cost-effectiveness model's outcomes for each patient and their spouse.

Outcomes measured

The primary outcome was the quality-adjusted life expectancy (QALE) when both husbands' and wives' preferences are used. The quality-adjusted life-expectancy is the number years a patient is expected to live, adjusted by a number from 0 to 1 which represents their quality of life, with 0 being death and 1 being an optimal state of health.

Results

When husbands' utilities are used, screening was associated with a QALE of 23.47 years, and not screening with a QALE of 24.14 years. When wives' utilities are used, the model calculated a QALE of 24.21 years for both screening and not screening. The model demonstrated that 7 of 10 men preferred the no screening strategy, while 9 of 10 women preferred to have their husbands screened. Women tended to assign a higher quality of life than their husbands to complications such as incontinence and impotence.

Recommendations for clinical practice

Husbands and wives may make different decisions about prostate cancer screening. The number of participants in this study is sufficient to raise questions, but further study into gender-specific differences is warranted. This study suggests that physicians need to consider who the family decision maker is, and highlights the value of informed consent in the decision to screen using PSA. Additionally, we should be prepared to arbitrate disagreement between husbands and wives!

References

1. Flood AB, Wennberg JE, Nease RF, Jr., Fowler FJ, Jr., Ding J, Hynes LM. The importance of patient preference in the decision to screen for prostate cancer. Prostate Patient Outcomes Research Team. J Gen Intern Med. 1996;11:342-9. 2. Wolf AM, Nasser JF, Wolf AM, Schorling JB. The impact of informed consent on patient interest in prostate-specific antigen screening. Arch Intern Med. 1996;156:1333-6. 3. Cantor SB, Spann SJ, Volk RJ, Cardenas MP, Warren MM. Prostate cancer screening: a decision analysis. J Fam Pract. 1995;41:33-41.

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TI - Predictors of interest in prostate-specific antigen screening and the
impact of informed consent: what should we tell our patients?

SO - Am J Med 1997;103(4):308-14

AU - Wolf AM; Philbrick JT; Schorling JB
AD - Department of Medicine, University of Virginia Health Sciences Center,
Charlottesville 22908, USA.
AB - PURPOSE: Screening for prostate cancer with the prostate-specific
antigen (PSA) remains highly controversial. We sought to discern
which patient factors predict interest in the PSA and how informed
consent impacts these predictors. PATIENTS AND METHODS: In a
randomized trial that found that informed consent decreases patient
interest in PSA screening, potential predictors of interest were
analyzed separately in the uninformed (n = 102) and informed (n =
103) cohorts to examine the effects of the informational interventio-
n. RESULTS: Univariate predictors of PSA screening interest (P <
0.05) among uninformed patients included perceived efficacy of
screening, perceived seriousness of an abnormal PSA, and willingness
to accept treatment risks. Among patients who had been informed about
PSA screening, univariate predictors included family history of
prostate cancer, perceived susceptibility to prostate cancer, age
(inverse association), and perceived efficacy, although informed
patients rated PSA efficacy significantly lower than uninformed
patients (P < 0.001). In multivariate logistic regression modeling
for the uninformed cohort, perceived screening efficacy (P < 0.001),
perceived seriousness (P < 0.05), and willingness to accept treatment
risks (P < 0.05) together were significant predictors of PSA
screening interest. Among informed patients, perceived efficacy (P <
0.001), perceived susceptibility (P = 0.01), and younger age (P =
0.01) together predicted interest in screening. CONCLUSIONS: In
contrast to uninformed patients, patients given information about PSA
screening and prostate cancer are more likely to be interested in
screening if they have a family history of prostate cancer, are
younger, or otherwise consider themselves susceptible to developing
prostate cancer. Uninformed patients are more likely to base their
screening interest on the perceived seriousness of prostate cancer
and on their willingness to accept treatment risks.