The researchers investigated whether there is a shift from left-sided toward right-sided colorectal cancer sites over time.
They also determined whether such a trend could be confirmed among hospitalized patients.
The findings of the study were published in the August issue of the Diseases of the Colon & Rectum.
Inpatient files of the Department of Veterans Affairs and the Surveillance, Epidemiology, and End Result database of the National Cancer Institute were analyzed. These were used to study the time trends of colorectal cancer in the United States during the past 3 decades.
| Increase in proximal colon cancer proportion over past 3 decades.
| Diseases of the Colon & Rectum |
Any cancer location in the rectum, sigmoid, or descending colon was defined as left-sided colorectum.
For the period between 1970 and 2000, the data from the Department of Veterans Affairs revealed a statistically significant 16% increase in the proportion of proximal lesions in white males and females. There was also a 22% increase among black males.
For the period between 1973 and 1997, the data from the Surveillance, Epidemiology, and End Result revealed a 6% increase in the proportion of proximal colon cancers among whites and blacks of both genders.
Dr Claudia Cucino, of the New Mexico Veterans Affairs Health Care System and the University of New Mexico, Albuquerque, concluded on behalf of her group, "The epidemiologic data confirm a rightward shift in the colonic distribution of cancer."