Rates of colorectal cancer in younger adults in Australia have stabilised amid an alarming increasing trend overseas, a new study has revealed.

But researchers from the University of Sydney who conducted the population-based study of more than 7 million people say that while the Australian data is encouraging, the impact of obesity and diabetes among children and young people might yet be realised in more colorectal cancer (CRC) cases among younger adults down the track.

They say that doctors need to be vigilant for symptoms among people under 50 years who are too young to participate in the National Bowel Cancer Screening Program.

Drawing on data from the NSW Central Cancer Registry, the study found that 32,178 people, were diagnosed with CRC between 1 January 2001 and 31 December 2008 – 6% of those patients were younger than 50.

Among the younger cases, the incidence rate was 13.7 per 100,000 in 2001 and 11.8/100,000 in 2008, a non-statistically significant change.  Among older people the incidence went from 79 to 83/100,000.

According to the study findings, the risk factors for early onset CRC included low socio-economic status, living in metropolitan areas and being born overseas.