Increasing colorectal cancer incidence in individuals aged < 50 years-a population-based study

Data on the incidence of colorectal cancer (CRC) is conflicting, and it is unknown if the incidence is constant, declining, or increasing. Proximal colon cancer is considered to be more common among older individuals, but recent data have shown that rectal cancer and distal colon cancer have been increasing in the younger population. The aim of this study was to determine the trends regarding CRC incidence and tumour location in Sweden.

CRC statistics from the National Board of Health and Welfare 1995-2015 were used. CRC incidence rates by age group (< 50 years, 50-79 years, ≥ 80 years), sex, and tumour localisation (proximal colon, distal colon, or rectum) were calculated and analysed using Poisson regression.

The age-standardised incidence of CRC increased in Sweden during the study period. This increase was significant (P < 0.0001) for colon cancer during the study period for all age groups regardless of tumour localisation. The greatest increase (27-52% per decade) in the colon cancer incidence rate was seen among men and women < 50 years of age. The incidence rate for rectal cancer increased for men < 50 years (P < 0.0001), decreased for both men and women aged ≥ 80 years (P < 0.005), and did not change for the remaining groups.

The CRC incidence in Sweden, in particular colon cancer, is increasing regardless of tumour localisation for individuals < 50 years of age. This paper supports the implementation of population-based colorectal cancer screening. A diagnostic workup should be performed in symptomatic individuals < 50 years of age.