In a recent analysis of US data, one in seven colorectal patients was younger than 50 years old, the recommended age to begin screening.

Younger patients were more likely to be diagnosed with advanced stage disease; however, they received more aggressive therapy and lived longer without a cancer recurrence, suggesting some compensation for their later diagnosis.

Published early online in CANCER, a peer-reviewed journal of the American Cancer Society, the findings raise questions concerning how younger adults' risk of developing colorectal cancer should be assessed, and whether or not they should be screened.

Colorectal cancer has traditionally been considered a disease of the elderly, but the proportion of cases in younger individuals is increasing.

To assess the treatment patterns and outcomes of these patients, a team led by Samantha Hendren, MD, MPH, of the University of Michigan, conducted a population-based retrospective study of the nationally representative Surveillance, Epidemiology, and End Results registry, looking specifically at information on patients diagnosed with colorectal cancer in the United States from 1998 to 2011.

Of 258,024 colorectal patients, 37,847 (nearly 15 percent) were younger than 50 years old, the age at which screening begins in the US.

(To put this in context, breast cancer screening often begins at age 40, and less than 5 percent of invasive breast cancers occur in women under that age.)

Young colorectal patients were more likely to be diagnosed with regional or distant disease, which are both more dangerous than localised disease.

Among colorectal cancer patients with distant metastasis, those who were younger were more likely to receive surgical therapy for their primary tumour (72 percent versus 63 percent of older patients).

Also, radiation therapy was used more often in younger than in older rectal cancer patients (53 percent versus 48 percent).

Overall, colorectal cancer patients who were younger than 50 years old lived slightly longer without a cancer recurrence, even though they tended to have more advanced disease when they were diagnosed.

The 5-year cancer-specific survival for younger patients was 95.1 percent versus 91.9 percent for patients 50 and older for localised disease, 76 percent versus 70.3 percent for regional disease, and 21.3 percent versus 14.1 percent for distant disease, respectively.

"This study is really a wake-up call to the medical community that a relatively large number of colorectal cancers are occurring in people under 50.

In a practical sense, this means that we should look out for warning signs of colorectal cancer such as anaemia, a dramatic change in the size or frequency of bowel movements, and dark blood or blood mixed with the stool in bowel movements," said Dr Hendren.

"Also, people with a positive family history for colorectal cancer (in first-degree relatives such as parents or siblings) and some others who are at higher risk should begin screening earlier than 50.

This is already recommended, but we don't think this is happening consistently, and this is something we need to optimise."

Source: Wiley