Although the absolute risk of bowel cancer in adults younger than 50 years is low relative to older adults, disease trends in young age groups are a key indicator of recent changes in risk factor exposures and often foreshadow the future cancer burden, according to Rebecca Siegel, MPH, a cancer epidemiologist, and Scientific Director of Surveillance Research at the American Cancer Society.[iv]A 2019 global study of seven high-income countries[vii] found in the decade up to 2014, Australia’s second deadliest cancer was rising in people under age 50. Published in the Lancet Gastroenterology and Hepatology, the research showed the number of Australians aged under 50 diagnosed with colon and rectal cancer increased significantly each year, by 2.9% and 2.6% respectively.
Currently, one in 10 Australians diagnosed with bowel cancer (and 5% of the people who die from this disease) are under the age of 50.
A 2020 Gold Coast study published in the ANZ Journal of Surgery[viii] found 21.5% of colonoscopies performed on patients under age 50 identified pathologies (adenomas); 1.9% of the patients were diagnosed with bowel cancer. All patients experienced symptoms, having cancer stage III (36.4%) or IV (45.5%) at diagnosis.
Of the top 10 cancers, bowel cancer is the only cancer in the 45-49 cohort to show an increase in mortality rates from 2008 to 2018, which is projected to continue through 2021, according to a Bowel Cancer Australia report[ix] authored by social demographer Bernard Salt AM in 2020.
The report revealed rising rates of bowel cancer among Generation Xers, particularly from age 45, noting a 72% spike in bowel cancer detection rates in individuals between the ages of 49 and 50. Of the cancers diagnosed, 45% were already at an advanced stage.
In Australia, the 45- to 50-year-old age group accounted for 615 diagnoses and 119 deaths from bowel cancer in 2019. Including people aged 45-49 in the National Bowel Cancer Screening Program (NBCSP) would expand the eligible population from around 6.7 million to 8.4 million.[x]
45 is the new 50, so how much longer must Australians wait for screening guidelines to catch-up?
Today a 45-year-old has the same bowel cancer risk a 50-year-old had 10 years ago, according to US Preventive Services Task Force (USPSTF) member Dr Alex Krist.[xi] The task force is a volunteer panel of doctors that regularly reviews evidence and issues advice on medical tests and treatments.
In May this year, the USPSTF published a report in JAMA[xii] recommending screening for all adults aged 45 to 75, and selective screening in adults aged 76 to 85.Although there are no randomised controlled trials specifically looking at the benefit of bowel cancer screening for the 45 to 50-year-old age group, studies and modelling looking at the 45 to 74-year-old age group provide some support for extending screening programs to include younger people.
Bowel Cancer Australia has been advocating lowering the screening age since 2018, in response to emerging evidence of rising rates of bowel cancer in people under age 50.
Adults born in the 1990s have twice the risk of colon cancer and four times the risk of rectal cancer than those born in the 1950s, according to US data.[xvi]
Cost-benefit modelling used to develop the 2017 NHMRC endorsed guidelines shows it is cost effective to lower the age of bowel cancer screening in Australia, for those aged 45-74; but the modelling suggests it would be associated with a less favourable incremental benefits-to-harms trade-off than screening from 50 to 74 years and would increase colonoscopy demand.
If we are to drive progress toward reducing bowel cancer incidence and mortality, Australia needs to start screening people from age 45, while also increasing participation rates among those aged 50 and over.
When detected in the earliest stage almost 99% of bowel cancer cases can be successfully treated.[xvii]
It took 14 years to fully implement the NBCSP, providing a faecal immunochemical test (FIT) to people aged 50-74 every two years (which only occurred in 2020).
If not for Bowel Cancer Australia’s advocacy, Australians would still be waiting until 2034 for a fully implemented program, as foreshadowed in the 2012-13 Federal Budget.
During the 12 years it took to update medical guidelines (2005-2017), nearly 15,000 people under age 50 were diagnosed with bowel cancer and 3,000 died.
If a 45-year-old today has the same bowel cancer risk a 50-year-old had 10 years ago, can we afford to wait another 12 years before medical guidelines address young-onset bowel cancer?
We must act now.
[i] Siegel RL, Torre LA, Soerjomataram I, et al Global patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185.
[ii] Feletto E, Yu XQ, Lew JB, St John DJB, Jenkins MA, Macrae FA, Mahady SE, Canfell K. Trends in Colon and Rectal Cancer Incidence in Australia from 1982 to 2014: Analysis of Data on Over 375,000 Cases. Cancer Epidemiol Biomarkers Prev. 2019 Jan;28(1):83-90. doi: 10.1158/1055-9965.EPI-18-0523. Epub 2018 Dec 7. PMID: 30530848.
[iii] Young, J.P., Win, A.K., Rosty, C., Flight, I., Roder, D., Young, G.P., Frank, O., Suthers, G.K., Hewett, P.J., Ruszkiewicz, A., Hauben, E., Adelstein, B.-A., Parry, S., Townsend, A., Hardingham, J.E. and Price, T.J. (2015), Early-onset colorectal cancer. J Gastroenterol Hepatol, 30: 6-13. https://doi.org/10.1111/jgh.12792
[iv] Siegel RL, Torre LA, Soerjomataram I, et al Global patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185.
[v] Siegel RL, Torre LA, Soerjomataram I, et al Global patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185.
[vi] Siegel RL, Torre LA, Soerjomataram I, et al Global patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185
[vii] Marzieh Araghi, Isabelle Soerjomataram, Aude Bardot, Jacques Ferlay, Citadel J Cabasag, David S Morrison, Prithwish De, Hanna Tervonen, Paul M Walsh, Oliver Bucher, Gerda Engholm, Christopher Jackson, Carol McClure, Ryan R Woods, Nathalie Saint-Jacques et al. Changes in colorectal cancer incidence in seven high-income countries: a population-based study. The Lancet Gastroenterology & Hepatology. 2019. doi: https://doi.org/10.1016/S2468-1253(19)30147-5
[viii] Kim, J., Dobson, B., Ng Liet Hing, C., Cooper, M., Lu, C.T., Nolan, G. and Von Papen, M. (2020), Increasing rate of colorectal cancer in younger patients: a review of colonoscopy findings in patients under 50 at a tertiary institution. ANZ Journal of Surgery, 90: 2484-2489. https://doi.org/10.1111/ans.16060
[xii] US Preventive Services Task Force. Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;325(19):1965–1977. doi:10.1001/jama.2021.6238
[xiii] Siegel RL, Torre LA, Soerjomataram I, et alGlobal patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185.
[xiv] Siegel RL, Torre LA, Soerjomataram I, et al Global patterns and trends in colorectal cancer incidence in young adults Gut 2019;68:2179-2185.
[xv] Schreuders EH, Ruco A, Rabeneck L, et al Colorectal cancer screening: a global overview of existing programmes Gut 2015;64:1637-1649.
[xvi] Rebecca L. Siegel, Stacey A. Fedewa, William F. Anderson, Kimberly D. Miller, Jiemin Ma, Philip S. Rosenberg, Ahmedin Jemal, Colorectal Cancer Incidence Patterns in the United States, 1974–2013, JNCI: Journal of the National Cancer Institute, Volume 109, Issue 8, August 2017, djw322. https://doi.org/10.1093/jnci/djw322