Colorectal Cancer Trends In Young Adults In Great Britain, 1975-2012

ORMISTON-SMITH N. ¹

Purpose
Colorectal cancer is less common in younger age groups, although a recent US study showed that the incidence of colorectal cancer is increasing in adults aged 20 to 49 years old (1).  By the end of the 1990s colorectal cancer incidence rates overall in Great Britain (GB) started to fall, but have since risen, particularly over the last decade (2). This may be associated with the introduction of the national bowel screening programme.

Methods
Trends in colorectal cancer (C18-20) incidence were analysed by age group to determine if there are differences to the overall trend or if similar trends were being seen as in the US.  Annual European age standardised incidence rates (ASR) for GB were calculated.  ASR trends between 1975 and 2012 were investigated using Joinpoint Regression Program for 20-34, 35-49, 50-74 and 75+ year olds.  A log linear regression model was used to calculate the annual percentage change (APC) between data points and test for significant differences in linear trends. 

Results
ASR increased significantly in 20-34 year olds since 1995 by 6% (5.4-7.1%) annually in GB.  In those aged 35-49 years the APC was 1.2% (0.4-2%) since 2002.

Conclusion
There has been a significant increase in the incidence of colorectal cancer in younger adults aged 20-49 years in GB similar to the trend in US.  It is predicted that as obesity in children increases colorectal cancer will continue to increase in younger adults.  Awareness of the increasing burden in younger age groups is important to ensure early detection and the importance of prevention measures early in life.

1. Bailey et al. Increasing disparities in the age-related incidences of colon and rectal cancers in the United States, 1975-2010 (doi:10.1001/jamasurg.2014.1756, 2015)
2. Cancer Research UK, http://www.cancerresearchuk.org/content/bowel-cancer-incidence-statistics. Accessed January 2016