Bowel cancer is also the deadliest cancer for Australians aged 25-44.
A recent study in Austria published in the JAMA, looked at the prevalence of bowel cancer and precursor (pre-cancerous) lesions in adults under 50 without symptoms. Precursor lesions include serrated lesions, adenomas, and advanced adenomas.
Adenomas are a type of typically small and benign tumour that develop in the glandular tissue of different organs throughout the body, including the colon, breasts, kidneys, and various glands.
Adenomas in the colon can increase the risk of progression to bowel cancer.
There are two types of adenomas – non-advanced adenomas, and advanced adenomas that are ≥10mm with villous histology (finger like projections) or high-grade dysplasia (severely abnormal cells).
The study examined 296,170 Austrians who have received a screening colonoscopy from 2008 to 2018, including 11,103 people under the age of 50.
According to the study, from 1988 to 2018, the incidence of bowel cancer decreased for those aged 50 and over, decreased for females under 50, and increased for males under 50. From 2008 to 2018, the prevalence of serrated lesions and adenomas increased across all age groups, and the prevalence of advanced adenomas increased in people aged under 50 and decreased in those aged 50 and older.
According to the study findings, the researchers recommended bowel cancer screening should commence at age 40 for males and at age 50 for females.
In October 2023, the National Health and Medical Research Council (NHMRC) in Australia endorsed updated clinical practice guidelines for bowel cancer screening.
These guidelines recommend, for people at average risk of bowel cancer and without symptoms, screening using a faecal immunochemical test (FIT) every two years between ages 45-74.
The guidelines also state a healthcare professional may consider offering a faecal immunochemical test every two years to people aged 40-44 who request screening, after being fully informed of the benefits and potential harms of testing.
