[Trends in the incidence of colorectal cancer at the Department of Côte-d'Or between 1976 and 1985]

Abstract

Colorectal cancer is the leading cause of cancer morbidity in France when both sexes are considered together. There are few available data on time trends, although such data would prove both necessary for planning screening programs and usefull to construct hypotheses on etiological factors. Data from the Registre des Tumeurs Digestives de Côte d'Or permitted to establish time trends for the different locations of colorectal cancer during the 1976-1985 period. Changes in incidence rates as based on the world reference population were studied using a log linear model as well as the Armitage test. Overall colon cancer rates have increased in both sexes. The mean annual increase of left colonic cancer was 3.1 p. 100 in men (p less than 0.05) and 4.0 p. 100 in women (NS), whereas rectal cancer decreased by 2.4 p. 100 in men and 3.3 p. 100 in women (NS). In men, left colonic cancer rates increased mainly in rural areas (+ 7.3 p. 100; p less than 0.05) whereas it increased mainly in urban areas in women (+ 6.0 p. 100; NS). In both sexes, the left colonic cancer increase was particularly noticeable in the 45-64 age group, which could indicate that the observed trend is likely to become more important in the next years. As for rectal cancer, the decrease was most important in the 65-74 age groups. That inversed trend for colon and rectum cancer has already been observed in other countries including the USA and Canada. As the trends we observed for right colon, left colon and rectal cancer differ, colorectal cancer etiology should be studied separately.