Should we be screening for colorectal cancer earlier?

By Kate Bass, B.Sc.Nov 7 2014

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in men and women. Last year it was estimated that there had been around 143,000 new cases of CRC and 51,000 deaths due to CRC in the United States. The introduction of bowel screening for the over 50s has seen annual decreases in the overall incidence of CRC since 1998, giving cause for optimism.

However, recent research shows that although the incidence of CRC is falling in people aged ≥50 years, it is increasing among 20–49 year-olds (below the age at which screening is recommended). Furthermore, it suggests that these patients are more likely to present with advanced disease, which is more difficult to treat.

A team of researchers at the MD Anderson Cancer Center, Houston, led by Christina Bailey, analyzed US incidences of CRC by age using data in the Surveillance, Epidemiology and End Results (SEER) registry. The analysis included data for all patients diagnosed with colon or rectal cancer in the US between 1975 and 2010 (a total of 393,241 patients).

The team found that the overall CRC incidence fell by 0.92% between 1975 and 2010. The decline in incidence was most pronounced in those aged ≥75 years (1.15%). Similarly, CRC incidence fell by 0.97% in those aged 50–74 years. The authors estimated that the incidence of CRC in people over 50 years will decrease by 23% by 2020 and by 41% by 2030.

However, CRC incidence rose by 1.99% in 20–35 year-olds, and by 0.41% in 35–49 year-olds. The authors estimated that by 2020 and 2030, the incidence rate of colon cancer in 20 to 34 years old will increase by 38% and 90%, respectively. They predicted even greater rises in the incidence of rectal cancers (50% by 2020 and 124% by 2030).

The team concluded:

The increasing incidence of CRC among young adults is concerning and highlights the need to investigate potential causes and external influences such as lack of screening and behavioural factors.

This research highlights the need for action to stem the increasing incidence of CRC in younger people. Future investigations should focus on determining why this increase is occurring and identifying the most appropriate CRC screening and prevention strategies for people aged 20–49 years.