Colorectal cancer rates rise most dramatically for adults in their 20s, a study finds

A team of researchers, including Rebecca L. Siegel, manager of surveillance information in the department of surveillance and health policy research at the American Cancer Society, conducted a study of colorectal cancer rates in people younger than 50. Siegel and her colleagues evaluated data collected on approximately 11,000 men and 9,800 women younger than 50 taken from 13 U.S. cancer registries that tracked information from 1992 through 2005. They found that colorectal cancer rates among the men increased 1.5 percent a year, with rates slightly higher -- at 1.6 percent a year -- for women younger than 50. Non-Hispanic white adults were especially at risk: rates rose 3.5 percent a year among men and 2.9 percent a year among women. This compares to overall annual rates across all categories of 2.8 percent and 2.2 percent among American men and women, respectively.

Moreover, the researchers found that every age category -- from 20 to 29, 30 to 39 and 40 to 49 -- experienced an increase. But surprisingly, for young adults between the ages of 20 and 29, rates were the highest: in this age category, rates rose 5.2 percent a year in men and 5.6 percent a year in women. As Siegel points out, in contrast to older populations, for which a drop in new diagnoses has been well established, the rates for younger adults are increasing fairly rapidly. In fact, of the American Cancer Society's estimated 41,000 new cases of rectal cancer this year, Siegel says that number will include approximately 15,000 people younger than 50.

“We aren't sure exactly what's going on," says Siegel. "But, clearly, I think the increased rates among younger adults, while low, are substantial and need some attention. For now we can say that there is obviously an obesity epidemic going on in the U.S., and so that probably has something to do with it. Also, there has been a change in dietary patterns over the past couple of decades, reflected in an increase in fast-food consumption and red meat consumption among young people. But whatever the cause,” she adds, “I would say clinicians should perhaps be more aware of the risks involved when younger people in their 20s and 30s come in with symptoms for what could be colorectal cancer. This current finding suggests that perhaps clinicians need to act on the risk a little bit more aggressively.”

Dr. Warren Enker, a colorectal surgeon and vice chairman of surgery at Beth Israel Medical Center in New York City, isn't surprised by the results of the study. "A dietary cause makes sense," he says. "If you take kids who are in an environment where the general caloric intake is higher, a sedentary lifestyle is more prevalent than it was 30 years ago and the type of food they're eating -- as regards red meat -- is higher, and then you put all of those things together, then there is no surprise that you have a rising incidence of colon cancer among younger people relative to others." However, other cancer colon specialists believe that additional research needs to be conducted to evaluate other potential factors that could influence colorectal cancer rates, such as smoking history and socioeconomic background.

News Release: Colorectal cancer rates rising for under 50 set  www.health.usnews.com   June 8, 2009