The urgency of saving lives through bowel cancer screening

One in 12 Australians will develop colorectal cancer (CRC), and it is the second most common cause of cancer death. It is one of only three cancers for which organised population screening is recommended, and it is the first to include men.1

Population screening for CRC appears effective and cost-effective. A meta-analysis of three large international randomised controlled trials showed that relative risk of the bowel cancer-related death rate in the screened group was, on average, 0.85, and that biennial screening was associated with a 13%–17% lowering of the bowel cancer mortality rate.2 The main harm arises from false positives; only 5%–6% of positive tests indicate cancer, while 40%–50% reveal polyps.

Australia’s National Bowel Cancer Screening Program (NBCSP) was introduced in May 2006 using the most up-to-date faecal occult blood test technology, known as a faecal immunochemical test (FIT).3 Initially, screening kits were sent only to those turning 55 and 65 years of age during the invitation period. In 2008, the program was extended to include those turning 50 years of age.4

An independent cost-effectiveness analysis of the NBCSP estimated that a full biennial FIT screening program for all Australians aged 50–74 years could save 500 lives each year.5 This estimate is conservative, but still is a good return on a government’s public health investment. Even an evaluation of the current limited program shows that almost triple the numbers of cancers were detected at the earliest stage compared with those that were only detected when they became symptomatic (40% v 14%). This early stage A disease has an 88% 5-year survival rate compared with 7% for the most advanced disease. In addition, over a 3-year period of the program’s follow-up, colonoscopies detected 2900 adenomas and 9400 polyps, which can be treated to prevent progression to cancer and will eventually become apparent as a reduction in CRC incidence.

Despite this strong evidence of benefit, and the expenditure of $43.4 million to introduce the screening program in the first 3 years ($30 million a year from 2008–09 on screening for the three age groups, and then the allocation of $138.7 million in the 2011 federal Budget to continue the current program), there has been no plan announced to expand the NBCSP to cover everyone aged over 50 years or, crucially, to reoffer screening every 2 years. International studies have shown, just as for breast and cervical cancer screening, that to achieve the demonstrated benefit, people will ideally repeat the test regularly.2

Economically, this is a cost-effective program, and it is affordable. Modelling by the Cancer Institute NSW in 2007 showed that phasing in a full NBCSP would cost only marginally more than Australia already spends on treating CRC.2 The offsets are the $1 billion estimated 2011 cost of treating established CRC, which includes hospitalisation and paying for the newer high-cost targeted drugs (such as cetuximab).2,6 There is also currently a 10% annual increase in the use of colonoscopy, which, in the absence of full coverage of the NBCSP, has been the adopted screening test for individuals at or slightly above average risk. In Australia, where colonoscopy is not considered to be the ideal initial screening test on the grounds of uncertain cost-effectiveness, broad population acceptance and equity of access, colonoscopy is probably used too often in people at average or slightly above average risk, as highlighted by the community survey by Courtney and colleagues.7 The use of colonoscopy should decrease with a fully implemented FIT program.7

An analysis by Cancer Council Australia showed that even if the NBCSP were to be expanded only incrementally, the addition of people aged 60 and 70 years would only add $15 million to the cost per year. Evidence is also emerging overseas that CRC screening can actually save costs.8 Of those sent kits, only about 40% participate in the program, with a slightly lower participation for males compared with females. Currently, 6.6% of those who complete an FIT kit return a positive result, but unfortunately, only about half the patients with this result proceed to diagnostic evaluation by colonoscopy when best practice dictates that all should be fully evaluated.9 These suboptimal rates are likely to be improved by a full publicity program that seeks to increase awareness of the need for, and value of, bowel cancer screening. But because the current scope of the NBCSP is so limited, no such publicity has been undertaken, in contrast to screening for breast and cervical cancer. Failure to mount an appropriate program detracts seriously from the credibility of the NBCSP in the eyes of the public. This is even more of a challenge in population subgroups where language and cultural barriers add to the lack of knowledge of the program, as described by Javanparast and colleagues.10

Expansion of the NBCSP to cover all Australians over 50 years of age, to include repeated screening every 2 years and to be accompanied by a credible publicity program is affordable and represents a sound investment in the health of Australians.