Screening men aged 80 and older for prostate cancer using a PSA test is common practice in many regions across the United States, but its frequency is highly variable. Nationally, nearly 20% of men aged 80 and older had a screening PSA test in 2003, yet clinical practice in some regions is essentially not to screen any man in this category (<2%), whereas in others, nearly 40% are screened. As the map shows (), regions with high screening rates are found across the entire United States, but low and high screening regions often directly abut one another, such as in Temple and Austin, Texas, or Flint and Lansing, Michigan.
The implication of this study is that there appeared to be little consensus in clinical practice on PSA testing of men aged 80 and older across regions before the age-based recommendation to stop screening was released. Yet low (near zero) screening rates in some regions, indicating some consensus within those HRRs, was surprising. In fact, the overall screening rate in this national sample of men was lower than reported in surveys and in the Department of Veterans Affairs (VA) system.4-7
Although survey data may lead to overestimation of screening rates,26
the regional differences in Medicare and the difference between Medicare and the VA findings (both calculated using claims) raise important questions about how different locations or payers influence screening rates; after all, screening is a clinical decision that is supposed to be highly individualized to a person’s health status and preferences.19
Any efforts to implement the USPSTF guidelines to cease screening at age 75 will need to take into consideration the baseline clinical practice in the local care system where intervention is proposed. The data from the current study show that this guideline may be controversial in high screening regions and possibly irrelevant in low screening ones.
With such large differences across regions, whether attributes of the regional delivery system are related to PSA screening at advanced age was asked. It was hypothesized that regions with high PSA screening rates would also have high use of testing and procedures in general for beneficiaries aged 80 and older, but it was found that all categories of usage except major procedures were higher in high screening regions. This exception of major procedures is difficult to explain but may suggest that these procedures, which entail higher risk, are handled differently from other types of care at advanced age. A surprisingly strong positive association was found between screening PSA and technologically aggressive end-of-life care in men aged 80 and older, considering that hospital-based and clinic-based processes were being compared. Higher rates of PSA screening in men aged 80 and older were also found in regions characterized by fragmentation of physician care and lower likelihood of using a primary care physician as the predominant provider. These associations taken together paint a picture in which very old men cared for in systems where advanced disease is treated aggressively and primary care providers have a less central role in care may be more likely to have a screening PSA test.
An alternative hypothesis to explain the regional variation is that the patients or doctors are in some way different across regions. Underlying health status could systematically vary across regions, a testable hypothesis that would be modeled best by incorporating functional status. Patient preferences for screening could also be different. Certainly enthusiasm for screening is high in the general public,27
but physicians appeared to initiate PSA screening more than patients. In a study of men who reported being screened, men aged 80 and older indicated the physician initiated testing 90% of the time.28
Physician attitudes are therefore likely to be important. Although attitudes may have changed, in 1995 primary care physicians highly favored PSA screening even in men aged 80 and older.28
In addition, practice in their region influences physician use of discretionary care.29
Further investigation of physician attitudes may be warranted, including how their normative behavior develops within a region or practice setting.
Much is already known about how to influence the process of prostate cancer screening decisions from clinical trials aimed at improving engagement of patients and provision of balanced information. Randomized trials using a standardized process of shared decision-making—the application of decision aids—have led to lower preference for screening and lower rates in the general population.30-34
The current literature suggests that men are not well informed, with 35% who had a PSA test reporting that they were unaware that they were screened, 69% reporting that the physician discussed only pros of screening and not cons, and other survey data showing poor knowledge of risks and benefits.35-41
To the authors’ knowledge, there are no published studies of decision aids that address the question of when to stop PSA screening, although it has been done for mammography.42
In the context of widely varying PSA screening rates in men aged 80 and older and consensus that many of these men would be exposed to more harm than benefit by screening, one path forward would be to institute better mechanisms for ensuring informed patient choice.
Several important limitations of this study need to be mentioned. These data are cross-sectional and do not support any causal relationships. The goal in comparing PSA screening with other clinical practices was to look for system-level factors worthy of future research. For example, further studies with a prospective design would be necessary to test the hypothesis that better-engaged and -informed men aged 80 and older would opt for PSA screening less frequently. As mentioned earlier, important relevant domains such as patient preferences and physician attitudes cannot be assessed. Future studies using a prospective design would also be needed to test whether an individual’s use of primary care independent of regional practices influences PSA screening. Claims data also have limitations in the accuracy of diagnosis, and hence there may be some contamination of the sample by men with prostate cancer. There is no reason to suspect this contamination would be different across regions, and it is likely that the broad exclusion criteria of prostate diagnoses, procedures, and symptoms led to conservative estimates of screening.
The 20-fold variation in the percentage of men aged 80 and older who receive PSA screening suggests that routine clinical practice patterns had not converged in spite of growing expert consensus in the early 2000s. With less than one-quarter of men in this age range likely to survive 10 years, screening rates in excess of that rate suggest that many men are being exposed to a test that poses more risk for harm than benefit. Whether efforts to inform patients better, strengthen primary care, or benchmark physician performance could reduce that exposure are questions that warrant further investigation. As we face rapidly increasing numbers of people aged 80 and older, the ability to apply current evidence in treatment of a population with limited life expectancy needs to be improved such that high quality is maintained while effective care is still delivered.