Preventive Checkups Open Door to Cancer Screening

SACRAMENTO, Calif., March 26 -- Health-plan patients who take advantage of periodic routine physicals are more likely to be screened for colorectal cancer, and for breast or prostate cancer, found researchers here.

Of patients who received a prepaid health exam in 2002 to 2003, colon cancer screening was three times higher compared with patients who did not have a checkup, Joshua Fenton, M.D., of the University of California, Davis here, and colleagues reported in the March 26 issue of the Archives of Internal Medicine.

Breast cancer screening for women was slightly greater among the checkup patients, while PSA testing for eligible men was almost three times greater.

These findings emerged from a retrospective cohort study to determine the association between preventive checkups and cancer testing in a population-based sample of 64,288 enrollees in a Washington State health plan (Group Health Cooperative). Participants were 52 to 78 years old and eligible for colorectal, breast, or prostate cancer screening.

Tests included completion of any colorectal cancer testing (fecal occult blood testing, sigmoidoscopy, colonoscopy, or barium enema), screening mammography, and PSA testing.

Overall, more than half (52.4%) of the enrollees received a checkup during the study period.

After adjusting for demographics, comorbidity, number of outpatient visits, 57.2% of checkup patients received colorectal screening versus 17.2% of patients who did not get checkups (adjusted relative incidence 3.47(95% CI, 3.34-3.59).

Among women who had preventive health exams, 74.1% had mammograms versus 55.9% of women without regular checkups (adjusted relative incidence 1.23, CI 1.20-1.25, P

Among eligible men, 58.8% given a checkup completed PSA testing, compared with 21.1% who did not (relative incidence 3.06 (CI 2.95-3.18).

The associations were particularly strong for colorectal cancer and prostate cancer, for which the health plan provides no centralized screening program, which it does for mammography, the authors wrote.

Although patients and physicians believe that preventive health exams are of proven value, there has been relatively little empirical support for the efficacy of the preventive health exam in health promotion or disease prevention, the researchers said.

The study, they said, provides timely confirmation and quantification of this association in population-based cohorts with confirmed eligibility for screening.

In discussing study limitations, the researchers wrote that they did not determine the presence of cancer symptoms in the study group and some colon cancer and PSA tests may have been done for diagnostic purposes rather than for screening.

If such symptoms led some enrollees to seek a "preventive" examination, and if physicians responded by ordering tests to diagnose cancer, then the results might overstate the impact of the preventive visit on cancer screening.

In addition, they said, misclassification of some covariates (benign prostatic hyperplasia diagnoses, for example) may have allowed residual confounding.

Unmeasured differences between patients who do and do not receive checkups may partly explain the observed differences in cancer screening. However, the investigators noted that they adjusted for the use of baseline preventive services to account for attitudes that may have predisposed patients to seek cancer screening and independently to adhere to physicians' recommendations.

Finally, they said, these findings may not be generalizable to uninsured populations or fee-for-service settings.

In similar populations, however, the preventive health exams may serve as a clinically important forum for the promotion of evidence-based colorectal cancer and breast cancer screening and of prostate cancer screening, which is not universally recommended, the investigators concluded.

"Experimental studies could confirm the efficacy of the preventive health examination in health promotion, elucidate the ideal content of preventive health examination, and guide the development of interventions to help physicians make the most of preventive health examinations," the researchers concluded.