Studying bowel cancer incidence in Australia
A team of Cancer Council researchers and collaborators has found that the incidence of bowel cancer in Australia increased in Australians under the age of 50. Research shows, however, that screening people 50-74 is still the best approach to reducing the impact of bowel cancer.
Background
Bowel cancer is the third most commonly diagnosed cancer in Australia, with around 16,000 new diagnoses estimated in 2019. The number of people diagnosed with bowel cancer under the age of 50 has risen in Australia as well as a number of high-income countries.
As 90% of bowel cancers can be successfully treated if detected early, finding bowel cancer early can significantly improve the chance of surviving the disease.
Australia’s National Bowel Cancer Screening Program (NBCSP) aims to reduce deaths from bowel cancer through prevention and early detection of the disease. By 2020, the program will invite all eligible people aged 50 to 74 to screen for bowel cancer every two years using a free, simple stool test kit which they can complete at home.
The research
The study found that the incidence of bowel cancer (colon and rectal) has increased in Australians under the age of 50. The yearly incidence rates having increased in colon cancer by 9.3% from the mid-2000s and by 7.3% in rectal cancer since the early 1990s. Conversely, the study also found that bowel cancer incidence decreased in Australians aged 50 or over which could be partially due to the NBCSP.
A complementary study explored extending the NBCSP to people in their forties, late seventies and early eighties, compared with the current age group. Screening people aged 50-74 was found to offer the best, balanced approach to population bowel cancer screening for average risk Australians. It was concluded that though there might be incremental benefits of screening people outside of this age range, they did not outweigh the associated potential harms. However, people aged 45–49 years can access screening, after being fully informed of the benefits and potential harms of testing, through their general practitioners (GPs) during the lead-up to the first routine invitation by the NBCSP at age 50 years.
The impact
This study suggests that a number of factors could be associated with bowel cancer risk in Australians under 50, including obesity, alcohol consumption and red and processed meat intake. To reduce overall cancer risk, but especially for bowel cancer, all Australians are encouraged to reduce their intake of alcohol and red and processed meat and maintain a healthy weight.
This research also reinforces how important it is that people who can access the NBCSP take part in the program because, if detected early, a large proportion of bowel cancers can be cured.
Research team
Cancer Council NSW and collaborators
Colorectal cancer incidence trends study:
Dr Eleonora Feletto (pictured)
Dr Xue Qin Yu
Dr Jie-Bin Lew
Associate Professor James St John
Professor Mark Jenkins
Professor Finlay Macrae
Dr Suzanne Mahady
Professor Karen Canfell
NBCSP age extension study:
Dr Jie-Bin Lew
Associate Professor James St John
Professor Finlay Macrae
Professor Jon Emery
Dr Hooi Ee
Professor Mark Jenkins
Dr Emily He
Paul Grogan
Dr Michael Caruana
Dr Marjolein Greuter
Dr Veerle Coupe
Professor Karen Canfell