Colorectal cancer on the rise among young Americans

Based on the latest SEER statistics from the National Cancer Institute, there were an estimated 1,177,556 people living with colorectal cancer in the United States in 2013. Colon and rectum cancer represents 8 percent of all new cancer cases in the U.S., and about 4 percent of men and women will be diagnosed with colon and rectum cancer during their lifetime.

The number of new cases of colon and rectum cancer was 41.0 per 100,000 men and women per year. The number of deaths was 15.1 per 100,000 men and women per year. [1]

While colon cancer is generally a concern for people older than 50, it has been in decline since 1974. For adults in their 20s and 30s, disease rates increased 1 to 2 percent every year from the mid-1980s through 2013, according to a new analysis of almost 500,000 people, published by researchers at the American Cancer Society.

Rectal cancer rates have increased even faster — rising about 3 percent every year from 1974 to 2013 in adults in their 20s. From the 1980s to 2013, rectal cancer rates for people in their 30s has increased 3 percent every year. [2]

“Trends in young people are a bellwether for the future disease burden,” said ACS researcher and lead author Rebecca Siegel. “Our finding that colorectal cancer risk for millennials has escalated back to the level of those born in the late 1800s is very sobering.”

Colorectal cancer starts in the colon or the rectum. These cancers can also be named colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.

Most colorectal cancers begin as a growth on the inner lining of the colon or rectum called a polyp. Some types of polyps can change into cancer over the course of several years, but not all polyps become cancer. The chance of changing into cancer depends on the kind of polyp. The two main types of polyps are:

• Adenomatous polyps (adenomas): These polyps sometimes change into cancer. Because of this, adenomas are called a pre-cancerous condition.
• Hyperplastic polyps and inflammatory polyps: These polyps are more common, but in general they are not pre-cancerous.

Dysplasia, another pre-cancerous condition, is an area in a polyp or in the lining of the colon or rectum where the cells look abnormal (but not like true cancer cells).

If cancer forms in a polyp, it can eventually begin to grow into the wall of the colon or rectum.

Many of the symptoms of colon cancer can also be caused by something that isn’t cancer, such as infection, hemorrhoids, irritable bowel syndrome, or inflammatory bowel disease. In most cases, people who have these symptoms do not have cancer.

Also, the relationship excess body weight and the risk of colorectal cancer is well established. Weight gain during adulthood can be regarded as an indicator of dynamic metabolic processes or adverse diet-lifestyle characteristics that might influence disease risk that maybe not adequately reflected by static obesity measures such as single point weight assessments. [3]

“It is not surprising that the timing of the obesity epidemic parallels the rise in [colorectal cancer] because many behaviors thought to drive weight gain, such as unhealthy dietary patterns and sedentary lifestyles, independently increase [colorectal cancer] risk,” Seigel said.