CRC is the third most commonly diagnosed cancer in Australia. In 2015 there were 15604 new cases (8573 males and 7031 females) It is estimated that in 2019 there will be 16398 cases newly diagnosed. The risk of an individual being diagnosed by their 85th birthday is 1 in 14. In 2016 it was the most common cause of cancer death in Australia. Despite the increasing numbers the survival figures from CRC has improved. Between 1986 -1990 and 2011-2015, five year relative survival from CRC improved from 52% to 70%.
Screening is recommended for a disease that is common and associated with serious morbidity and mortality, has a screening test that is sufficiently accurate for detecting early stage disease and is acceptable to patients, and where treatment after the detection by the screening process shows a better outcome than those treated after usual diagnosis. Screening is for those without any symptoms or risk factors as opposed to surveillance which is for those with risk factors. In the general non risk population the incidence of CRC is 1% and adenomatous polyps is 25% at age 50. However it should be noted that 19 out of 20 adenomatous polyps do not develop into cancer. About 75% of all new cases of CRC are in those that have no known predisposing factors for the disease.
Currently screening consists of faecal occult blood testing. This is made available free of charge to all Australians from the age of 50 years and every 2 years after that till the age of 74 years.
The screening test made available is an immunochemical based test (FIT) that requires a sample from 2 different stool specimens and does not require any change to diet or medication prior to the test being taken. This test uses globulin antibodies to detect blood. Previously the Guaiac based test that was used had a strict diet and medications to avoid hence making it more difficult to comply with. A stool DNA test (Cologaurd) is available in the USA which looks for both DNA changes and blood in stool. It is claimed that it can detect 92% of cancers but only 42% of precancerous polyps. It has a 13% false positive rate. This test did get FDA approval in 2014 in the USA and plans are to introduce this for screening. A study in The New England Journal of Medicine compared Cologaurd with FIT looking primarily at sensitivity for advance neoplasia. Findings are shown below:
At this stage it is not available in Australia and not recommended over the current FIT due to the lower specificity rate .
Currently with the FIT test about 1 in 14 people undergoing the test will test positive. Studies have shown that those patients testing positive going on to have a colonoscopy;
However the problem with any screening program is the level of participation. Data from AIHW National Bowel Cancer Screening Programme showed the little change in the participation rate between 2007/8 and 2015/16 with rates of 43.5% and 40.9% respectively. Female participation was higher than males and persons aged 65-69 (51%) were more likely to participate than those from 50-54 years (32%).
Currently the consensus in Australia is that from the age of 50 and every 2 years till the age of 74 undergo a FIT test.
Dr Shevy Perera, MBChB, BHB, FRACS
Dr Dayashan (Shevy) Perera is an Expert Colorectal Surgeon specialising in laparoscopic minimally invasive (“keyhole”) surgery. He has performed over 2,000 laparoscopic bowel resections, making him one of the most experienced laparoscopic Colorectal Surgeons in Australia.
Dr Perera has been in practice for 15+ years and is actively involved in training new surgical registrars. He was Director of Surgical Training for the Southern Surgical Network from 2002-2008 and the Treasurer of the Medical Staff Council at St George Public Hospital from 2008-2012. He is currently the Supervisor of Colorectal Fellowship Training at St George Public Hospital.
Dr Perera’s main interests include advanced laparoscopic colorectal surgery and hernia surgery. He also an accredited robotic surgeon, using the cutting edge da vinci robot on patients when indicated.