In a poster to be presented at the upcoming annual meeting of the American Society for Clinical Oncology (ASCO) on Sunday, June 3, Allen et al. have compared the PSA levels of previously tested American men to the PSA levels of American men whose PSA level had never previously been assayed.
The data were collected from participants in a recent cohort of the population-based National Health and Nutrition Examination Survey or NHANES study, which accumulates a wide range of health-related information and blood specimens from a nationally representative sample of the entire U.S. population.
In the current study, Allen et al. were able to collect a variety of relevant data as well as blood samples from 3,980 men, all aged between 40 and 69 years of age and surveyed between 2003 and 2008:
- 2,078 men had had at least one prior PSA test (“screened” patients)
- 1,902 men had never had a prior PSA test (“unscreened” patients)
The men were stratified by age group (40-49 years; 50-59 years; and 60-69 years), and their PSA values by age group are shown in the table immediately below:
Allen et al. were able to use the accumulated data to demonstrate the following:
- Increasing age was associated with a higher probability of a prior PSA test.
- Only 25 percent of men in the 40-49 year age group had had a prior PSA test.
- 56 percent of men in the 50-59 year age group had had a prior PSA test.
- 72 percent of men in the 60-69 year age group had had a prior PSA test.
- Screening rates were higher among
- Men with a known family history of prostate cancer (68 vs. 50 percent) compared to those with no family history
- Men with health insurance coverage (58 vs. 21 percent) compared to no health insurance coverage
- Caucasians (59 vs. 44 percent) compared to non-Caucasians
- No significant differences were observed in the relative PSA values of screened vs. unscreened men when stratified by age, by family history, by race/ethnicity, or by health insurance status.
- Very few men under age 60 years had a PSA level > 10 ng/ml.
These data are inherently interesting, but it is difficult to know exactly what to make of them other than to say that they confirm that the PSA test is not exactly a definitive test for risk of clinically significant prostate cancer in population-based cohorts of individuals.
It does seem highly likely, based on these data, that many men never get an initial PSA test until they qualify for health insurance under Medicare — given that only 21 percent of men without health insurance had had a prior PSA test and that 72 percent of men in the 60-69 year age group had had a prior PSA test (compared to much lower percentages in the younger age groups).