Potential years of life lost due to prostate cancer in the USA: 1972-2006

An analysis published by Kamel et al. in the Journal of Urology earlier this year offers an estimate of the potential years of life lost (PYLL) due to prostate cancer in seven 5-year periods between 1972 and 2006. (Prostate cancer was the most prevalent of several forms of urogenital cancer addressed in this report.)

Before providing the actual data, we should be clear about what is meant by PYLL.

PYLL is a mathematical estimate of the cumulative number of potential years of life that have been lost due to premature death as a result of a specific cause within a specific population. Estimates of PYLL are based on relatively sophisticated computations (and the authors provide details of the equations used in their computations). From a basic viewpoint, however, readers should understand that the authors made the assumption that the average life expectancy in the USA for the time period from 1972 to 2006 was 75 years. (The actual average life expectancies in 1972 and 2006 were 70.2 and 78.2 years respectively.) Thus, for the purposes of this study, PYLL due to prostate cancer in the USA was being estimated in terms of years of life lost relative to the average lifetime of 75 years.

Kamel et al. give the following data for prostate cancer:

You will observe that the estimated PYLL appears to have peaked in the period between 1987 and 1996, correlating with the approximate introduction and early widespread use of the PSA test. It can be argued that the introduction of the PSA test facilitated the diagnosis of large numbers of men with progressive forms prostate cancer who, today, can reasonably be expected to get diagnosed much earlier in the course of their disease. It is harder to make a specific determination about why the PYLL dropped over the period 1997 to 2006. Potential reasons certainly include earlier diagnosis (as a consequence of PSA testing) and better treatment (due to improvements in surgical technique and in the capabilities of radiation therapy in its various forms).

The bottom line is that the PYLL for prostate cancer in 2006 was about the same as it was in 1972.

To offer some additional context for the data given above, it may be useful to be able to compare the PYLL due to prostate cancer to the PYLL due to another exclusively male form of urogenital cancer — testicular cancer, for which PYLL have dropped significantly over the same time period because of improvements in the efficacy of chemotherapy (to which Lance Armstrong can personally attest):

In this case, clearly, there was an initial, rapid drop in PYLL between 1972 and 1986 followed by a slower, steady drop from 1987 to 2006. The overall decline in PYLL for testicular cancer over the 35-year time frame has been about 58 percent.

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