We found that screening rates have changed over time. Between 2003 and 2005, colorectal endoscopy screening rose, Pap testing was stable, PSA testing dropped, and as previously reported, mammography dropped.22
The lowest screening rates were found for persons without a usual source of care, those who had no physician contact in the past year, and the uninsured. The patterns of disparities we found in 2005 were consistent with those found in previous years of the NHIS.18
A review of other studies shows that factors associated with disparities have remained similar over recent years.7,18,23-25
However, it is important to note that, after adjustment for the other variables studied, race/ethnicity and immigration status did not yield significant differences in test usage for distinct racial-ethnic groups. It was the factors more directly related to the individual's interaction with the health care system that resulted in significant disparities.
The only cancer site for which screening increased in 2005 was colorectal, and this was due to an increase in use of endoscopy. Even when test rates increased, people without insurance or physician contact were not screened. These patterns of disparities are most clearly illustrated by colorectal endoscopy use in 2005, after the period of rapid uptake (). The tables show that, among the uninsured, 2005 endoscopy rates were 6.5% for women and 14.1% for men. Rates were similarly low for those who did not see or talk to a physician within the past year. Even for women and men who saw a doctor within the past year, screening rates were conspicuously low, 7.3% and 8.0%, respectively.
Though use of all the modalities was strongly influenced by contact with a physician, its effect on PSA use was particularly striking. Forty-five percent of men who saw or talked to a doctor in the past 12 months reported a PSA test; in contrast, among men who did not report physician contact, only 9.8% reported the test.
As the nation considers changes to health care, it is critical to rely on scientific evidence of the effectiveness of clinical guideline dissemination. There are three essential components to the successful delivery of cancer screening: coverage, guidelines, and tracking systems.26
Few health plans in the United States had all three in place in 2000. Group and staff model HMO plans were far more likely than other types of plans to have any system at all for screening delivery.26
Successful cancer screening systems require the alignment of plans and clinician efforts at the practice level.27
By accomplishing that, and by adhering to cancer screening guidelines and a tracking system, Veterans Affairs medical centers had higher screening rates than surrounding communities in 2004.28
The greatest benefit from screening would come from extending such a delivery system to people who have never been screened for cancer according to the guidelines. Now, more than ever, we need to bring proven delivery strategies to those individuals.29
Two large public health efforts are doing that. CDC's Breast and Cervical Cancer Program has increased mammography and Pap testing rates, but it appears to be underfunded.30,31
NCI's Cancer Collaborative Project with the Health Resources Services Administration (HRSA) is enhancing primary care services in underserved areas to include cancer screening referrals, follow-up, and treatment.32
Even so, evidence-based cancer screening coverage of underserved populations remains incomplete.
Study limitations include the use of self-reported data and exclusion of institutionalized and non-civilian populations. In addition, American Indian, Alaska Native, Asian American and Pacific Islander samples were too small to analyze separately and were included in a “non-Hispanic other” group. We report on receipt of endoscopy within 3 years, but screening guidelines indicate an interval of 5 years for sigmoidoscopy and 10 years for screening colonoscopy. Therefore, we underestimate the percentage of the population that is “up to date” for colorectal screening using current guidelines. Other studies have suggested that about 50% of the eligible population is currently in compliance with colorectal screening guidelines.12,16,33-35
Survey questions are not always identical from year to year, a limitation that was especially problematic for our analysis of endoscopy. Another change in data collection in 2005 reduced the number of missing responses and slightly altered recent screening rates.