Colorectal cancer among Asian Americans

Abstract

The Asian ethnic subgroups that migrated to the USA are experiencing an increase in colorectal cancer (CRC) rates. This is in contrast to the decline in invasive CRC incidence reported for non-Hispanic whites in the USA, which has been widely attributed to an increase in screening rates. Studies have shown that at least some of the Asian ethnic subgroups are less likely to undergo screening. A number of lifestyle-related factors have been associated with CRC. Indeed, the evidence for a causal link between certain types of dietary factors (e.g., dietary fiber, folate, calcium, vitamin D, red meat, processed meats), alcohol, medications, obesity and physical inactivity and CRC is stronger than for any other common types of cancer. However, it has been suggested that differences in the distribution of known/suspected lifestyle risk factors account for only a portion of the excess risk in Asian Americans for CRC and that other factors, possibly including genetic susceptibility (in particular, gene-environment interactions), are important contributors to the observed disparities in incidence. Based on the available evidence, it is unlikely that risk factors for CRC in Asians differ markedly from those in non-Hispanic whites and other ethnic/racial groups. Further research is warranted to better understand the relationship between genetic and environmental factors that increase the CRC risk of Asians when they migrate to the USA. Most importantly, utilization of screening services should be further promoted to reduce the incidence of this disease in Asian Americans.