Colon Cancer Incidence Rises Dramatically For Young People in Their 20s and 30s

MedicalResearch.com Interview with:
Rebecca L. Siegel, MPH

Surveillance and Health Services Research
American Cancer Society
Atlanta, GA 

MedicalResearch.com: What are the main findings?

Response: It was known that colorectal cancer incidence rates are declining rapidly in people 50 years and older, but curiously increasing in people younger than 50 years. For a more comprehensive understanding of incidence patterns, we examined CRC incidence trends by 5-year age group and year of birth using age-period cohort analysis. This modeling technique helps enhance the understanding of disease trends by disentangling factors that influence all ages (period effects) from those that vary by generation (birth cohort effects).

In incidence data for almost 500,000  colorectal cancer patients during 1974-2013, we found both period and cohort effects. However, the period effects were dwarfed by the cohort effects. The age-specific risk of colorectal cancer declined during the first half of the 20thcentury, but has increased for subsequent generations since around 1950, such that those born in 1990 have twice the risk of colon cancer and 4 times the risk of rectal cancer compared to people born in 1950. Said another way, someone in their 20s today is 4 times more likely to be diagnosed with rectal cancer than someone who was in their 20s in 1970. The risk for contemporary generations has escalated back to that of people born circa 1890.

MedicalResearch.com: What are the main findings?

Response: We also found that incidence rates are not only increasing for people younger than 50, but also for those 50-54 years, who are currently recommended to be screened. Because of declining rates in ages 55-59 years coinciding with increasing rates for those ages 50-54 years, the risk of disease today for people in their early 50s is the same as it is for people in their late 50s, whereas two decades ago the risk for people in their early 50s was just half that of people in their late 50s. For example, in 1990 the incidence rate for rectal cancer was about 30 (per 100,00) for ages 55-59 years and 15 for ages 50-54 years, but in 2013 it was 25 for both age groups.

MedicalResearch.com: What should readers take away from your report?

Response: It is important for the general public and primary care physicians to be aware that the risk of  colorectal cancer is rising for young adults, with the largest increases for those in their 20s and 30s. Even young patients with symptoms consistent with  colorectal cancer (e.g., bleeding from the rectum or in the stool, abdominal cramping, changes in bowel habits or bowel shape, unexplained weight loss, etc.) should be followed up in a timely manner to rule out cancer. Young patients are 60% more likely than older patients to be diagnosed with distant stage disease because of delayed follow-up and obstacles to care because of no health insurance.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: Future research should focus on different etiologies and carcinogenic mechanisms between proximal tumors and distal/rectal tumors, which are driving this increase.

No disclosures.

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Citation:

Colorectal Cancer Incidence Patterns in the United States, 1974–2013
Rebecca L. Siegel, Stacey A. Fedewa, William F. Anderson, Kimberly D. Miller
Jiemin Ma, Philip S. Rosenberg, Ahmedin Jemal
J Natl Cancer Inst (2017) 109 (8): djw322.

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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