Major Finding: The incidence of colorectal cancer among those aged 40-44 years increased 50% between 1987 and 2006 (from 12 per 100,000 to 18 per 100,000).
Data Source: An analysis of data from the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) database.
Disclosures: Dr. Davis reported that he had no relevant financial relationships; senior author Dr. Jorge Marcet reported that he has significant financial relationships with GlaxoSmithKline and two surgical device manufacturers.
MINNEAPOLIS — An increase in the national incidence of colorectal cancer among individuals who are younger than age 50 years has prompted some experts to call for lowering the screening age to at least 40 years.
Although the colorectal cancer (CRC) incidence across all age groups has decreased 18%—from 55 per 100,000 in 1987 to 45 per 100,000 in 2006—the incidence among those aged 40-44 years increased 50% during that same period, from 12 per 100,000 to 18 per 100,000.
The findings are based on an analysis of data from the National Cancer Institute's SEER (Surveillance, Epidemiology, and End Results) database, which includes information on the incidence, prevalence, and survival from specific geographic areas representing 26% of the U.S. population.
“This has led us to the conclusion that the screening age for colorectal cancer for average-risk persons should be reduced to at least 40 years,” Dr. Donald Davis said at the meeting.
Currently, it is recommended that CRC screening begin at age 50 years for those with average risk.
The researchers looked at yearly data from 1987 to 2006 for five age groups, ranging from 0-4 years to older than 85 years.
They then examined data from 2002 to 2006 to determine the location of colorectal cancers and the incidence by age for CRC, colon cancer, and rectal cancer.
Overall, colon cancer dropped 17% and rectal cancer decreased 18%. People older than 50 years had a lower incidence of CRC in 2006 than in 1987.
However, those aged between 20 and 50 years had higher incidence in 2006 than in 1987.
Colon cancer increased 40% and rectal cancer increased 63% among those aged 40-44 years during this period.
Regarding the location of tumors, the highest percentage (approximately 30%) was in the rectum. More than half were located in the in the rectum or sigmoid.
For comparison, the researchers also looked at the change in cervical cancer incidence.
“We used cervical cancer because it is considered a successfully screened cancer,” said Dr. Donald Davis, a surgical resident at the University of South Florida in Tampa.
In the 1970s, the incidence of cervical cancer was approximately 15 per 100,000; today, it is about 8 per 100,000. Current recommendations are to begin screening women for cervical cancer by age 21.
The incidence of cervical cancer peaks among women aged 40-44 years (15 per 100,000), according to recent data. The incidence of CRC is equal to that of cervical cancer in this age group, Dr. Davis noted.
“However, after this age group, colo-rectal cancer exponentially increases while cervical cancer continues to decline,” he said.
The researchers were prompted to look for a national trend based on the results of an institutional review. They found that 100 patients younger than 50 years had been diagnosed with CRC in the past 7 years. “The results were not evenly distributed. There was an exponential increase among those aged 35-40 years,” said Dr. Davis.