INTERVAL CANCERS IN COLORECTAL CANCER SCREENING , JAPAN －Cancer registry and Screening –
METHODS: We collated the data from 170,231 individual screenings for colorectal cancer conducted between Apr. 1st ,2004 and Mar. 31st ,2009 with the FUKUI Cancer Registry, to measure sensitivity and specificity and to identify the colorectal cancers diagnosed outside cases of the screening program with fecal occult blood test. Interval cancers are defined the false negative cases that diagnosed outside of the screening program within two years after screening examination.
RESULTS: The 64 interval cancers and 300 screening cases were detected, so sensitivity and specificity were 0.82 and 0.95 respectively. Mean age of interval cancer; 71.5 years-old is significantly higher than that of screening cases; 67.1. StageⅣ cancers were 17.2% in interval cancers and 6.6% in screening cases. There were no histological difference between interval cancers and screening cases. The 5-year relative survival rates for colorectal cancer were calculated 91.2% as screening cases and 88.3% as interval cancers. Hazard ratio of interval cancers is 2.47.
CONCLUSIONS: Mortality of colorectal cancer is not significantly decreasing in Fukui prefecture. One reason why that the annual rate of StageⅣcancer has remained almost unchanged. Mass screening system seems to be effective for early diagnosis and treatment of colorectal cancer. So we must continue to observe further trends in mortality for colorectal cancer, and to improve public participation in mass screening examinations. Furthermore, we must do the effort to decrease the interval cancers. This data is useful for cancer control planning of local government.