The Centers for Disease Control and Prevention conducted a National Health Interview Survey and found only 50 percent of men and women 50 and older had received screening in 2005. Although this was an improvement over the 43 percent of screened individuals reported in 2000, it is still far from optimal, investigators say.

"Colorectal cancer is one of the leading cancer killers in the United States, behind only lung cancer. Screening has been shown to significantly reduce mortality from colorectal cancer, but a lot of people are still not getting screened," said Jean A. Shapiro, Ph.D., an epidemiologist at the Centers for Disease Control and Prevention (CDC).

Shapiro says a major problem appears to be insurance coverage. Among people without health insurance, researchers found the rate of colorectal cancer screening was 24.1 percent compared to over 50 percent of insured Americans, depending on the type of insurance. Among patients without a usual source of health care, the screening rate was 24.7 percent compared to 51.9 percent of patients with a usual source of health care.

"If we can increase the number of people who have health care coverage, we should be able to increase colorectal cancer screening rates," said Shapiro.

Shapiro says the increase in colorectal cancer screening rates observed from 2000 to 2005 may have been due in part to increased media coverage of the importance of colonoscopy as a measure to prevent cancer and detect it early, including a broadcast of Katie Couric, then co-host of NBC's Today show, undergoing a colonoscopy. However, Shapiro adds, the increase was probably also due to the fact that in 2001, Medicare expanded its coverage for colonoscopy screenings to a wider range of patients.

"Health care access and insurance are important," Shapiro said.

Beyond health insurance, researchers at the CDC reported the following factors influenced the use of colorectal cancer screening tests:

• Education: 37 percent of people with less than a high school education received screening vs. 60.7 percent of college graduates.
• Household income: 37.4 percent of people earning less than $20,000 in annual household income received screening vs. 58.5 percent of people earning $75,000 or more.
• Frequency of physician contact: 19.5 percent of patients who had not seen a physician in the past year had received screening vs. 52.5 percent of patients who had seen their physician two to five times in the previous year.

Approximately 50 percent of patients who did not receive testing said they had "never thought about it," while about 20 percent said their "doctor did not order it," researchers found.

"Many doctors are aware, but some may still need to be educated about the importance of colorectal cancer screening," said Shapiro.

These data were derived from the CDC's 2005 National Health Interview Survey which interviewed 30,873 adults in a demographically representative sample of Americans. Interviews were conducted in person with a 68 percent response rate. For the current analysis, Shapiro and colleagues focused on 13,480 patients who were age 50 and older.

Note: If no author is given, the source is cited instead.

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