Benefit of PSA test, prostate cancer screening falls for older men

17 November 2005. The benefits of prostate cancer screening decline with age because of the long natural history of prostate cancer and competing causes of death among older men, says H. Ballentine Carter, in the journal Urology.

Carter and his team developed a computerized mathematical model of prostate cancer detection in men aged 40 to 90 years and simulated prostate cancer screening in 1000 populations of 1,000,000 men each.

The age at the final prostate-specific antigen test in the model was varied to simulate the discontinuation of screening from age 50 to 80 years. The model outputs were the number of men treated, the number of prostate cancer deaths prevented by treatment, and person-years of life saved.

The relationship between treatments required to prevent a death was not constant but widened with age. Compared with screening to age 65 years, screening to age 75 and 80 years required twice and three times, respectively, the number of treatments per person-year of life saved.

For every 1,000 men screened at the age of 60 years, 85 cancers would be treated and 14.7 deaths prevented. In contrast, for every 1,000 men aged 65, 75, and 80 years at the time of final screening, 102, 149, and 177 cancers would be treated, respectively, and 16.9, 21.3, and 22.9 deaths would be prevented.

Although increasingly more prostate cancers are found in a group of aging men, treating these cancers saves proportionally fewer lives and fewer years of life than treating prostate cancer in men younger than 65 years of age.

Twice as many prostate cancers would be treated for each life-year saved if screening were stopped at 75 years of age rather than at 65 years of age, increasing to three times as many where screening were continued until 80 years of age.

"Our results have helped to quantify the declining treatment benefit as the patient age at screening and treatment for prostate cancer increases," Carter said. "We believe that men older than 70 years should be carefully counseled about the declining benefits of prostate cancer detection with screening."