Sa1036 FOLLOW-UP COLONOSCOPY IN COLORECTAL CANCER SCREENING REMAINS EFFECTIVE AMONG ELDERLY INDIVIDUALS WHO SHOW POSITIVE FIT RESULTS

Abstract

Both American College of Physicians and U.S. Preventive Services Task Force recommend for people aged 75 and over to consider stopping the screening for colorectal cancer (CRC). But in Japan, there is no guideline about the ages of CRC screening, a lot of people over 75 years are receiving fecal immunochemical test (FIT) for mass screening for CRC, and consequently, a good number of elderly people undergo a follow-up exam, colonoscopy (CS). Because CS has possible severe complications, the follow-up CS among elderly people should contribute to CRC screening no less than among younger people. We investigated the efficacy of the follow-up CS among individuals over 75 years old, by comparing the results of the follow-up CS with those among younger individuals. This retrospective study was carried out in a single center. A total of 1336 subjects (657 men; 679 women) who underwent CS based on the positive result of FIT were enrolled. After dividing them into two groups, over 75 years (group A, 589 subjects) and 75 years or less (group B, 747), the detection rate of CRC, the rate of invasive CRC, treatment methods, CRC sites, and the detection rate of any neoplasm (CRC or adenoma) were determined. χ2 test was used for statistical analysis. The detection rate of CRC showed no significant difference between group A and B (8.8%, 52 out of 589 subjects; 7.5%, 56 out of 747, respectively). However, the rate of invasive CRC was significantly higher in group A than B (69%, 36 out of 52 CRC subjects; 41%, 23 out of 56, respectively, P < 0.005). As a result, 58% in group A needed surgery, on the other hand, 34% in group B underwent surgery (P < 0.015), and the others were endoscopically treated. CRCs were more frequently detected in the right side colon in group A than B (59%, 32 out of total 54 CRC lesions; 28%, 17 out of 61, respectively, P < 0.005). There was no significant difference in the total neoplasm detection rate between group A and B (53%, 312 out of 589 subjects; 55%, 411 out of 747, respectively). Individuals over 75 years who underwent the follow-up colonoscopy showed no significant difference in the detection rates of CRC or neoplasm compared with the younger individuals. However, CRCs detected in the individuals over 75 years were more deeply invasive and were more frequently seen and predominant especially in the right side colon than the younger individuals, where CRC is thought to be more difficult in early detection without any symptoms than in the left side. Taken together, we believe that CRC screening after the age of 75, using FIT and the follow-up CS, may have some efficacy.