Abstract
The burden of follow-up studies using total colonoscopy for patients with colorectal adenoma has been growing due to an increase in morbidity for colorectal neoplasia. We are therefore proposing a new follow-up scheme to address this problem. This scheme classifies patients into two categories according to the findings of colonoscopy following a positive result of fecal occult blood test (FOBT). One of them includes patients with mildly or moderately atypical protruding-type adenoma with a diameter of less than 5 mm (Group A). The other includes patients with severely atypical or surfaced-type adenoma (Group B). The former group was followed up with rounds of total colonoscopy every five years combined with annual FOBT. and the latter was checked every one to three years with total colonoscopy. Patients in Group A and B participated in a mass screening in 1997 and underwent total colonoscopy as a diagnostic examination. For comparison, we identified patients with adenoma who participated in a mass screening in 1996 and underwent a diagnostic examination as well (Group C). They were followed up with rounds of total colonoscopy every one to three years, irrespective of the size of their lesions. We tracked those groups up to the year 2002 and compared the intervening time before the next colonoscopy, compliance with the examination, and the extent of colorectal lesions that required therapeutic interventions (carcinoma, adenoma with a diameter of more than 5 mm or with severely atypical change). There were no significant differences between three groups in the compliance of patients with the follow-up study (80.9% in Group A, 85.3% in Group B and 83.0% in Group C). The intervening period of Group A (31.1 months) was significantly longer than that of the other two groups (21.2 months in Group B and 18.7 months in Group C). The hazard ratio for detecting lesions that required therapy was 0.41 for Group A vs. Group C and 1.45 for Group B vs. Group C. These findings indicate that our new scheme can identify patients with low potentiality for further colorectal adenoma and can decrease the burden borne by the patient. It can also enable physicians to pay more attention to patients who required more cautious follow-up studies.
