Annual Report on Colorectal Cancer

Colorectal cancer (CRC) incidence has been declining in the U.S. since about 1985, except for a slight increase in rates between 1995 and 1998, which has sometimes been attributed to the introduction of folic acid supplementation in flour. Now, the authors of an annual report on multiple cancers provide an update on incidence and mortality in CRC and use microsimulation modeling to interpret past trends and project future trends. The authors obtained information about invasive cancers from the National Cancer Institute, the Centers for Disease Control, and the North American Association of Central Cancer Registries. Here are highlights of the report.

• CRC incidence and mortality both declined markedly during 1997 to 2006; the average annual decline in CRC mortality was 2.7% during this interval.

• The fastest annual rates of decline in CRC incidence during 1997 to 2006 were seen in men and women aged 65 and older.

• Half of the 22% overall decline in CRC incidence during 1975 to 2000 was attributable to screening.

• 35% of the 26% overall decline in CRC mortality during 1975 to 2000 was attributable to changes in risk factors (e.g., a decline in smoking rates); 53% of the overall decline was attributed to screening, and 12% was attributed to improvements in treatment.

• If current trends in risk factors, screening, and treatment were to continue unchanged as of 2000, a 36% overall decline in CRC mortality could occur between 2000 and 2020; if these trends were to accelerate, a 50% overall decline in CRC mortality could occur by 2020.