Two articles in the October issue of the Canadian Urological Association Journal address the issue of how good (or bad) physicians are at actually assessing the life expectancies of individual patients and the correlated issue of how one then determines whether to test specific individuals for prostate cancer risk (or treat them if you find cancer).
The initial paper by Leung et al. reports on a study conducted among about 100 Canadian physicians. The study was designed to try and identify the accuracy with which physicians could accurately project the life expectancies of seven different patients (not specifically patients with prostate cancer). Since the full details of the paper are available on line, you can read it for yourself if you want to. The bottom line was that
- Respondents generally underestimated the life expectancies of the patients described.
- The sex, level of training, workplace, and specialty of the respondents seemed to have no significant impact on the accuracy of their predictions.
- Respondents’ estimates of life expectancy were within 1 year of actual life expectancy only 15.9 percent of the time.
- Respondents were inaccurate in relation to actual survival 67.4 percent of the time, on average.
- Respondents were able to estimate which patients would live for more or less than 10 years 68.3 percent of the time.
Leung and his colleagues conclude that, “Physicians do poorly at predicting life expectancy and tend to underestimate how long patients have left to live.” This is not a new finding, but the authors go on to point out that this degree of inaccuracy does raise all sorts of questions about whether physicians need to refine screening and treatment criteria, find some other way to address such criteria, or just get rid of the criteria altogether.
To be fair to physicians, accurate assessment of the life expectancy of an individual man or woman is extraordinarily difficult. If it wasn’t, you can be quite sure that those in the health and life insurance business would have worked out how to do it well by now!
The problem, as it applies specifically to prostate cancer, is that without an accurate assessment of the life expectancy of an individual patient, how does one make good decisions about when a specific man no longer really need to go on getting PSA tests, or whether he really needs to be treated if he is diagnosed with low- or intermediate-risk prostate cancer?
In an associated editorial in the same journal, Siemens accurately observes that
The “layers of uncertainty” … that have resulted from this knowledge gap have complicated our ability to communicate and support our patients, especially those who are considering PSA testing or contemplating their preferred management for localized disease.