The study is the first to find significant differences in the cost-effectiveness of current screening techniques among blacks, whites, Asians and Latinos, and suggests that current recommendations on screening for cancer of the colon and rectum (known as colorectal cancer) be modified to adapt to these ethnic differences. The study appears in the March issue of Gastroenterology.

Dr. Charles Theuer, assistant professor of surgery and a practicing cancer surgeon at UCI Medical Center, Hoda Anton-Culver, chief of UCI's division of epidemiology, and colleagues found that colorectal screening, detection and treatment programs would be more effective if started earlier among blacks, whites and Asians. Currently, the American Cancer Society recommends colorectal cancer screening to begin at age 50 for people of "average" risk.

Colorectal cancer is diagnosed in about 131,000 Americans every year; at the same time, about 55,000 people die from the disease. It is the second-highest cause of death from cancer in the nation. If detected early by screening methods such as a flexible sigmoidoscope or laboratory tests for blood in the stool, it usually can be treated successfully.

"While nearly all colon cancer could be treated if everyone was screened at an early age, not enough cases are found at early ages for public health agencies and health-care providers to devote the labor and costs necessary for early screening," Theuer said. "The recommendations of screening at age 50 may be effective for the population as a whole. But our study shows large variations in the way cancer develops among ethnic groups, suggesting that we need to change the timing and techniques of screening and tailor them to each group."

The researchers, using the large NIH Surveillance, Epidemiology and End Results (SEER) database and California cancer registries, found that colorectal cancer rates were highest among blacks and lowest among Latinos when adjusted for age. While screening at age 50 among all groups more than justified the costs of screening and treatment, the researchers predicted that earlier screening among certain groups would result in more cancer treatments and lives saved which would more than justify the costs of beginning the screening at an earlier age.

Specifically, screening programs (which include lab analysis of stool blood, sigmoidoscopy and full colonoscopy) that began at age 42 among blacks, age 44 among whites and age 46 among Asians were more effective, the researchers found. Latinos, who had the lowest prevalence of colorectal cancer when adjusted for age, could be screened effectively at age 50, in accordance with current recommendations, the study suggests.

"Incidence rates of colorectal cancer among blacks and other ethnic groups have always been known to be high," Anton-Culver said. "Our study shows that Americans are not at all homogeneous when it comes to cancer rates, and we need to adjust our health recommendations to accommodate this diversity."

Anton-Culver warns that public health officials and physicians should continue to encourage more screening for colorectal cancer, regardless of ethnic background. "Lower rates among Asians and Latinos should not indicate that those groups do not need screening. These rates may be due to higher immigrant populations whose cancer rates may change as they adopt more Western diets and lifestyles."

Theuer's and Anton-Culver's colleagues in the study included Judith Wagner of the Congressional Budget Office, Washington, D.C., and Thomas Taylor, Dr. Wendy Brewster, David Tran and Christine McLaren of UCI. The research was supported by a grant from the National Cancer Institute and from the V Foundation, Cary, N.C.