We’ve made incredible progress in preventing colorectal cancer, primary through the use of effective screening and prevention strategies, particularly colonoscopy. The incidence of colon cancer in the United States is 30% lower now, compared to 10 years ago, and continues to decrease 2-3% every year. This is quite remarkable. Screening adults age 50 and older is effective. But what we are now seeing is an increasing rate of colon cancer among younger adults. That is, adults who fall outside the typical screening recommendations.
A recent study, published in the Journal Cancer1, showed that 1 in 7 (15%) of all colon cancers diagnosed between 1998 and 2011 occurred in individuals below the age of 50. This is a trend we are observing in clinical practice, and is substantiated by these data. The current study utilized data from the Surveillance, Epidemiology, and End Results (SEER) database, which is the definitive source for cancer incidence and survival data. These are real numbers, and they are troubling. Not only are we seeing more cancer in individuals below the age of 50, but the cancers are more advanced. This is because they are found after symptoms develop, not during an asymptomatic screening exam.
An earlier study2 in 2015 showed that colon cancer (all stages) is decreasing in adults age 50 years and older, but increasing in adults age 20-34 and 35-49.
The question is how to reverse this trend. At this time, screening is not recommended for average-risk individuals below the age of 50. The American College of Gastroenterology does recommend screening African Americans at age 45, though this is not endorsed by all guidelines. Family history is an important risk factor for colon cancer, and individuals with a family history of colon cancer or colon polyps should begin screening at an earlier age (typically, age 40 or younger, depending on the family history).
Otherwise, we need to pay particular attention to symptoms, particularly blood in the stool, and seek evaluation for any such changes. Ultimately, we may need to re-evaluate the current screening guidelines should these trends continue.
Christopher McGowan, MD, MSCR
1. Abdelsattar, Z. M., Wong, S. L., Regenbogen, S. E., Jomaa, D. M., Hardiman, K. M. and Hendren, S. (2016), Colorectal cancer outcomes and treatment patterns in patients too young for average-risk screening. Cancer. doi: 10.1002/cncr.29716
2. Bailey CE, Hu CY, You YN, et al. Increasing disparities in the age-related incidences of colon and rectal cancers in the United States, 1975–2010. JAMA Surg. 2015;150:17-22.