Fecal Occult Blood Testing: Best Option for Colorectal Cancer Screening in Asia?
Authors: S. P. Sharma
Journal: JNCI Journal of the National Cancer Institute (2008)

F ecal occult blood testing (FOBT) is the most cost-effective method of colorectal cancer screening in at least some Asian countries, according to a new study from the Chinese University of Hong Kong. The study, which compared FOBT to two other screening methods, flexible sigmoidoscopy and colonoscopy, highlights the increasing concern about colorectal cancer in a region where incidence of the disease has risen markedly in the past few decades. Colorectal cancer is now the second most common malignancy in many Asian countries, and in some places the incidence, distribution, and mortality rates of the disease are similar to those of the West. This increase may be due to rapidly changing lifestyles and diets. Forthcoming new regional guidelines on colorectal cancer screening reflect the sense of urgency that some experts feel about the upward trends. But in some countries in the region, colorectal cancer incidence remains low, provoking debate on whether screening should be a priority for all. The new study, published in April in Alimentary Pharmacology and Therapeutics , evaluated the cost-effectiveness of screening with FOBT annually, sigmoidoscopy every 5 years, or colonoscopy every 10 years in a hypothetical population of 100,000 people aged between 50 and 80 years who were at average risk for colorectal cancer. Using the mathematical Markov model, the authors factored in the prevalence of the disease, the cost of screening procedures, compliance rates, and the cost of treatment. Assuming 90% compliance, and compared with no screening, FOBT required an extra $6,222 to save an additional lifeyear; sigmoidoscopy, $8,044; and colonoscopy, $7,211. At lower levels of compliance (50% and 30%), FOBT still remained more cost-effective. The researchers acknowledge that their findings differ from those of some studies in Western countries that have shown colonoscopy to be the most costeffective screening method. “Our re sults may seem to be in conflict with the others, but we have some distinct differences in the study that are important to know,” said Joseph J.Y. Sung , M.D., Ph.D., an author of the study and a professor of medicine at the Chinese University of Hong Kong. “We based our assumptions on data from Asian countries [with a high incidence] like China, Japan, Korea, Taiwan, and we decided to screen from 50 years to 80 years instead of screening until death,” he said. “The most important thing is that our model also incorporated the cost of new chemotherapy regimens for different stages of advanced [colorectal cancer] in the cost analysis.” The last decade in Asia has seen improvement in colorectal cancer survival rates due mainly to advances in chemotherapy, such as the use of oxaliplatinand irinotecan-based therapy and targeted therapies. The Asian findings are consistent with the experience in at least one country outside the region. In Israel, the averagerisk population is screened with FOBT, and, according to Gad Rennert, M.D., Ph.D., head of the country’s breast and colorectal cancer detection program, the test has a high detection rate and is costeffective. Rennert noted that Israel uses an immunochemical test that has a higher sensitivity than the guaiac-based test used in the Asian study. Had data from i m m u n o c h e m i s t r y entered the model, he said, the result would have been even more dramatic.