Special Report: Colorectal cancer is starting younger — and growing obesity rates may be the reason.

Last year, the American Cancer Society found the disease was occurring among people in their 20s and 30s at a rate of one to two per cent higher than in the mid-1990s.

Colorectal, or bowel cancer, strikes most commonly from age 50 — the age when Australian adults start receiving their ‘at home’ faecal testing kits.

But the US research suggests that people born in 1990 and later now have double the risk of colon cancer of those born around 1950.

A study by the JAMA Network suggested that obesity is associated with an increased risk of early-onset colon cancer, although warned that further research is needed to confirm the link.

Australian government figures show that bowel cancer is still an older person’s phenomenon however, starting to affect obese adults from around age 45 onwards.

This is concerning as local data shows that 28 per cent of adults in this country counted as obese in 2015, compared to just 8 per cent a decade earlier.

A quarter of children were also deemed to be overweight or obese in 2015.

A report by the Australian Institute of Health and Welfare last year into weight and chronic disease did highlight the obesity-bowel cancer relationship however, labelling the cancer as one of 22 diseases associated with the condition.

It found that overweight and obesity contributed 12.8 per cent of bowel cancer’s total burden on Australian society (financial and ill health) and this was almost three times higher for men (18 per cent) than for women (6.4 per cent).

Rhythm Biosciences chief Trevor Lockett, previously a long-time researcher into gut health with CSIRO, says the problem for younger people is not necessarily colon cancer per se, but rather the impact of their diets, lifestyles and overweight status today on their bowel cancer risk tomorrow.

“There can be a 10 to 15 year lag between events that initiate the cancer cascade and the appearance of bowel cancer in individuals.”

“It’s a disease that has a big environmental component to it as cancer risk can be substantially influenced by the foods we are eating and our exercise habits. And clinical symptoms that things might be going awry are pretty subtle, only becoming more apparent as the disease progresses.”

“There is a real need for pre-symptomatic screening as we become older to maximise our chances of detecting disease early.”

Early intervention is key

Dr Lockett’s company Rhythm Biosciences (ASX:RHY), which listed on the ASX almost one year ago, is developing a blood test called ColoSTAT to improve the way colon cancer is diagnosed.

The test uses antibodies to measure the levels of proteins in the blood that vary in the presence or absence of colorectal cancer.

It offers an alternative to the ‘poo-and-post’ faecal test adults receive in the mail when they turn 50 and must send off after taking it.

The process can turn many people off and potentially decrease uptake of screening initiatives.

Dr Lockett says the combination of rising obesity rates and the potential for younger people to develop colon cancer shows that the need for effective, yet simple testing is increasing.

“The survival rate for colon cancer is highly dependent on how advanced the cancer is at time of diagnosis – essentially, how soon you catch it.”

“If we can simplify and streamline the diagnostic process and intervene early, we can improve treatment outcomes and cut down on the costs associated with treating the disease in the long term.”

Rhythm remains on track to complete delivery of its key reagent development program, or the antibodies and proteins whose interactions underpin its ColoSTAT test, by the end of this year.


Rhythm Biosciences is a Stockhead advertiser.

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