Australia ranks poorly in global CRC audit

Australia and New Zealand have one of the world’s highest overall incidence rates of colorectal cancer, according to the latest global audit.

The review of 185 countries’ GLOBOCAN records found Australia and New Zealand had an overall incidence rate of 33.2 new cases per 100,000 person-years, when grouped by region.

For context, Northern Europe bore the greatest burden of 20 assessed regions, with 33.6 new cases per 100,000 person-years, while South Central Asia had the lowest at just 5.5.

It comes despite Australia’s overall downward trend in colorectal cancer rates, due to effective screening programs and the “removal of precancerous lesions in older adults, as well as changes in lifestyle factors, including the declines of smoking prevalence”, the paper, linked here and published in Gut, read.

Part of the problem may lie in increasing incidence among adults under 50, likely driven by the “progressive adoption of a more westernised diet” and “rising rates of overweight and obesity”, it suggested.

Unhealthy diet, constituting high amounts of red and processed meat, sugary drinks and low fruit, vegetable and dietary fibre intake, along with high alcohol consumption; physical inactivity; and excess body weight are known modifiable risk factors for colorectal cancer and many of these have increased since the 1950s, the authors noted.

“However, prospective data linking these and other suspected risk factors with early-onset CRC are currently lacking and further high-quality studies are needed,” they conceded.

While Australia and New Zealand had one of the worst incidence rates, they came mid-pack for mortality.

Overall, the countries recorded 9.5 deaths per 100,000 person-years in 2020, where Central Eastern Europe had 14.5 and South Central Asia had 3.2.

“Numerous studies have shown incidence and mortality rates in high-incidence transitioned [high Human Development Index] countries have stabilised or are in decline”, with the largest decreases seen in countries with longstanding programs, the authors wrote.

“While many countries offer screening at 50 years of age, participation remains low in many settings, despite well-organised programs.

“To this effect, countries should focus on the implementation and uptake of guideline-recommended screening programs,” they said.

There was further discussion about lowering the screening age, given the increasing incidence among younger adults.

Already, the American Cancer Society and US Preventive Services Task Force has dropped the recommended age of average risk screening from 50 to 45, though “recommendations are commonly based on modelling due to lack of empirical evidence”.

“The impact of implementing [a] younger screening age should be closely monitored to assess if it should be introduced in other countries”, the authors wrote, concerned that lowering the age might divert resources and screening capacity from “older adults who are at higher risk”.

“Determining the associated risk factors within this age group that would enable primary prevention strategies should be a priority,” they wrote.

This will be critical in coming years, as global incidence and mortality rates are set to grow from nearly 2 million new CRC cases and 930,000 deaths in 2020, to 3.2 million and 1.6 million in 2040, with most cases expected to occur in high Human Development Index countries like Australia.

Improved screening and symptom awareness could also help limit the impending CRC burden, the authors suggested.

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