Surveillance of High Risk Individuals with Family History using Guaiac Test (Hemoccult II)

Abstract

From 1979 to 1989 at Istituto Nazionale Tumori of Milan, 2,629 individuals at high risk for Family History of Large Bowel Cancer (first degree relatives) were screened by guaiac test combined with endoscopy. The test was positive in 95 patients (3.6%), 88 out of them (92%) and 545 H− (21.5%) accepted the endoscopic examinations. 27 colorectal cancers (21 H+, 6 H−) and 89 patients with adenomas (23 H+, 66 H−), mostly in the left side of bowel, were detected. During the follow-up (median 67 mths) 1,492 individuals (60%) were rescreened: 5 cancers and 50 pts. with adenomas were detected. Instead in the non responders group 3 cancers and 4 adenomas were diagnosed (median interval between cancer, adenoma in H-: 26 mths, 24 mths). The overall prevalence for cancers was 1.3% and 5.5% for adenomas. The sensitivity of the test for cancers and adenomas was calculated in about 77% and 29% with a specificity of 98%. The data confirm the opportunity to screen individuals at high risk for family history suggesting annual rescreening.