The recently revised National Comprehensive Cancer Network guidelines for the management of prostate cancer emphasize the importance of life expectancy in estimating individual patient risk of prostate cancer mortality — particularly for those patients with low- and very low-risk disease.
Kim et al. have now published a methodology that should allow physicians, when counseling newly diagnosed patients, to more effectively communicate the risk for death from prostate cancer as compared to the risk of death from competing causes through an estimate of the patients’ lifetime risks of prostate cancer-specific mortality.
The process uses a special form of actuarial life table (“double decrement” life tables) to calculate age-specific mortality rates using data from the Social Security Administration life tables and Gleason score-specific mortality rates reported from a pre-PSA cohort study. The new life tables provide life expectancy and risk for prostate cancer death based on age at diagnosis, Gleason score, and other factors.
The authors offer the following example: A 60-year-old prostate cancer patient with a Gleason score of 7 has an overall life expectancy 10.2 years based on the pre-PSA cohort data. His risk for prostate cancer-specific death during these 10.2 expected years of life is 49 percent. However, if it is assumed that early detection as a consequence of PSA testing introduces a 10-year “lead-time bias,” the patient’s risk for death from prostate cancer decreases to 26 percent. Furthermore, if the patient was in the bottom (poorest) quartile for overall health and his disease was detected by prostate examination, the risk for death from prostate cancer was 32 percent.
The authors have developed a Web-based tool that allows online performance of these computions. Unfortunately, however, this tool is not as user-friendly as we believe it needs to be, and most patients would find it difficult to apply in its present form. We hope that this online tool can be improved because it offers a potentially very useful way to estimate lifetime risk of prostate cancer mortality — particularly for those with low- and very low-risk disease who are considering active surveillance as an appropriate form of management for their disease.
Editorial addition: Since posting the above material early this morning, we have been advised by Roswell Park Cancer Center that they are very conscious of the need to improve the above-mentioned Web page and are working hard to be able to offer a significantly more user-friendly version of their lifetime risk estimator as soon as possible. We will keep readers informed of relevant developments.