Incidence of colorectal carcinoma in the US - An update of trends by gender, race, age, subsite, and stage, 1975-1994

BACKGROUND. Colon carcinoma incidence rates have risen sharply over the sec ond half of this century, particularly among males and blacks. In the late 1970s, incidence rates among whites began to decline for distant disease. A pproximately 10 years later regional disease rates began to fall. The decli ne in incidence rates among whites largely has been attributed to more wide spread colorectal carcinoma screening. However, similar trends by stage in blacks have not been observed. METHODS. The incidence of colorectal carcinoma was evaluated by race, gende r, age, and stage of disease for each subsite using data from > 220,000 cas es diagnosed between 1975 and 1994 in the U. S. Surveillance, Epidemiology, and End Results program. RESULTS. Recent data have continued to show a decrease in incidence rates o f total colorectal carcinoma in whites since the mid-1980s, particularly fo r the distal colon and rectum. Overall, proximal colon carcinoma rates were higher than distal colon or rectal carcinoma rates throughout the study pe riod. Proximal colon carcinoma rates in blacks were considerably higher tha n in whites and continued to increase, whereas rates in whites showed signs of declining. The age-specific and stage-specific bends for proximal colon carcinoma in blacks were not consistent with the possibility of earlier di sease detection through screening. CONCLUSIONS. Etiologic studies are necessary to understand the large increa ses in the incidence of proximal colon carcinoma among blacks. (C) 1999 Ame rican Cancer Society.