The ten-year rule revisited: accuracy of clinicians' estimates of life expectancy in patients with localized prostate cancer.

OBJECTIVES

To determine the accuracy of clinicians' predictions of life expectancy in patients with localized prostate cancer, when provided with information about age and comorbidity, and to determine whether life expectancy estimates predict the choice of initial treatment.

METHODS

A survey was sent by facsimile to 191 Canadian urologists and radiation oncologists asking them to estimate the life expectancy and choose the initial therapy (radical prostatectomy, radiation, or watchful waiting) for 18 patient scenarios: two prostate cancer scenarios, each with three ages and three levels of comorbidity.

RESULTS

Life expectancy estimates were accurate within 1 year of the projections of a Markov model for 31% of the clinicians' responses and accurate within 3 years for 67% of the responses. The average prediction error ranged from 2.4 to 5.2 years. The life expectancy was correctly estimated as being greater than or less than 10 years in 82% of responses. Ten years was the minimal life expectancy for recommending surgery and within the range (5 to 15 years) in which radiation was recommended.

CONCLUSIONS

Clinicians can use age and comorbidity to predict the life expectancy of patients with localized prostate cancer with a modest degree of overall accuracy, but with sufficient accuracy to use the "10-year rule." Life expectancy estimates are strongly associated with treatment choice. The appropriateness of the 10-year rule remains to be determined.