Colorectal cancer (CRC), also known as bowel cancer, is cancer in any part of the large bowel (colon or rectum). It’s the second most common cancer in Australia and accounts for around 10% of all cancer deaths nationally. Outcomes of CRC are largely dependent on the stage at which it is diagnosed.

Research has found that faecal occult blood testing (FOBT), a method of screening, increases the identification of early-stage CRC and reduces risk of death from the disease.

Australian guidelines have recommended screening using FOBT for asymptomatic people aged 50 years and over at least every two years however CRC screening tests were not freely available until 2006.

In 2006, the National Bowel Cancer Screening Program (NBCSP) was launched. This involved a one-off FOBT being mailed to all people turning 55 and 65 years. From 2008, this expanded to include people turning 50. There are few data ascertaining the effects on CRC incidence related to opportunistic screening that might have taken place prior to the NBCSP.

Researchers present data on the relationship between CRC screening history and the incidence in Australia.

Study participants were part of the 45 and Up Study in NSW. Information was gathered from self-administered questionnaires. Participants were asked if they had ever been screened for CRC and, if so, which test they had undergone and their most recent year of testing. Cancer incidence was ascertained from the NSW Central Cancer Registry.

The results found that having ever been screened before the beginning of the study was associated with a 44% reduced risk of developing CRC during the study follow up when compared to those who had never been screened.

Reduction rates were 40% for ever having had FOBT and 50% for endoscopic screening procedures – both compared to never having undergone CRC screening. The reduction in risk was most pronounced for rectal cancer.

Implications

The results of this study show a lower risk of CRC in people with a history of screening compared to those who had never undergone screening. This suggests a benefit for following current bowel cancer screening guidelines.

Last Reviewed: 26/11/2019

Norman Swan Medical Communications



References

Steffen, A et al. (2014). Colorectal cancer screening and subsequent incidence of colorectal cancer: results from the 45 and Up Study. MJA 201 (9) doi: 10.5694/mja14.00197.

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