Hemoccult tests are insensitive for upper gastrointestinal cancer

BACKGROUND: Fecal occult blood (Hemoccult) screening followed by colonoscopy has been shown to reduce colon cancer mortality, but uncertainty remains about the utility of upper endoscopy in further evaluation of patients with positive Hemoccult testing. This study addressed the risk of upper gastrointestinal cancer in patients whose Hemoccult test results are positive.

POPULATION STUDIED: The researchers used a cohort of 61,933 people aged 45 to 75 years in a defined region of Denmark who were followed from 1985 through 2000. They excluded patients with known colorectal neoplasia and distant metastases. The results from this population are likely to apply to the usual US family practice, although the researchers did not provide information about age distribution, dietary habits, alcohol or tobacco history, cancer history, or ethnicity, factors that may influence the development of upper gastrointestinal cancers.

STUDY DESIGN AND VALIDITY: Subjects were drawn from the screening arm of a population-based randomized trial of colon cancer screening. A total of 30,967 patients were offered the screening. After education about diet and medications, subjects were given nonrehydrated fecal occult blood tests biennially. Patients with positive Hemoccult tests were interviewed and examined, and underwent colonoscopy or double-contrast enema; those with carcinoma and/or adenoma were enrolled in a surveillance program. Upper endoscopy and other studies were performed only if warranted by symptoms. The county databases, supplemented by death certificates, the Danish National Register of Patients, and the National Cancer Register, were used to obtain information about malignant disease. Upper gastrointestinal cancers were defined as cancer of the esophagus, stomach, small intestine, and biliary and pancreatic systems. The sensitivity and positive predictive values of Hemoccult testing were calculated using all upper gastrointestinal cancers developing within 2 years.

OUTCOMES MEASURED: The primary outcomes were the sensitivity and positive predictive value of the Hemoccult test with respect to upper gastrointestinal cancer. Cost, patient and physician satisfaction, and impact on quality of life were not addressed.

RESULTS: From 1985 through 2000, 473 patients were diagnosed with upper gastrointestinal cancer in the overall study population, 199 of whom had upper gastrointestinal cancer diagnosed within 2 years of a negative fecal occult test. The sensitivity and positive predictive value of fecal occult blood for upper gastrointestinal cancers diagnosed within 2 years of a positive test were 4.8% and 0.57%, respectively. The presence of symptoms or anemia did not improve the performance of fecal occult blood as a screening test for upper gastrointestinal cancers.