On average, the trials lasted six years, entailing volunteers who took either aspirin or a dummy lookalike pill called a placebo. The doses ranged up to 1200 mg. Out of 14,033 patients whose health could be traced 18 years or so since the trial, 391 had colorectal cancer, the investigators found. Taking aspirin reduced the risk of cancer by 24 per cent and the risk of dying from it by 35 per cent. The results were consistent across all four trials – and there was no increase in benefits beyond a dose of 75 mg. Where the reduction was most remarkable was in cases of proximal colon cancer. These occur in the upper colon and are thus liable to be missed in lower-intestine scans for polyps, the precursor of tumours. The authors say their study had limits, as the original trials were not designed to look at aspects of colorectal cancer, nor was data available for any deaths from aspirin’s side effects. Also, aspirin’s benefit may have been somewhat over-estimated, they said. This was because the original trials took place before colon screening for polyps became a routine practice in those countries. Even so, the evidence has now swung the scales in favour of low-dosage aspirin for a disease that claims 600,000 deaths worldwide each year, they said.
Colorectal cancer screening knowledge, attitudes and behavioural intention among Indigenous Western Australians
Endoscopic screening is often carried out without a prior FOBT examination. “We saw quite clearly that the greater proportions of men and women who were screened, the greater the reductions in mortality,” Prof Autier will say. “Reduced death rates from CRC were not noticeable in countries where screening was low, even though healthcare services in those countries were similar to those in countries where screening was more widespread.” In Austria, where 61% of all those studied reported having undertaken a FOBT, deaths from CRC dropped by 39% for men and 47% for women during the period. In Greece, however, where only 8% of males had had an endoscopic examination as opposed to 35% in Austria, death rates from CRC rose during the period by 30% for men and 2% for women. Overall, in all the European countries studied, 73% of the decrease in CRC mortality over ten years in males, and 82% in females, could be explained by their having had one or more endoscopic examination of the large bowel over the last ten years. “The evidence could not be clearer,” Prof Autier says, “and it is therefore very disappointing that national differences in the availability of CRC screening programmes are still so pronounced.” The researchers believe that the large differences in screening rates between different European countries are due to a number of factors. “First, many countries still do not have a national CRC screening programme. Second, the acceptability of screening methods is often low, sometimes due to cultural differences between countries. There is also the question of the availability of qualified personnel. In some countries, there are insufficient gastroenterologists available to perform endoscopy. Even with FOBT screening, an endoscopy is needed if the test is positive,” says Prof Autier. Since the main goal of CRC screening is to remove polyps in the bowel, the risk of over-diagnosis is low, unlike that seen in breast and prostate cancer screening. “The risk of bowel perforation with endoscopy, while not non-existent, is very low and so far no trial has reported rates of perforation that could compromise the feasibility of screening on either practical or ethical grounds,” Prof Autier says. The researchers now intend to gather further data on screening and to include those from the USA, Canada, and Australia. “There are signs that CRC screening can reduce the incidence of this cancer as well as mortality from it, in exactly the same way as is happening with cervical cancer screening. We would also like to investigate the cost-effectiveness of CRC screening, since we believe that it has the potential to bring about economic gains associated with averted CRC cases and deaths, and hence to more than pay for its initial cost,” says Prof Autier.
additional resources http://medicalxpress.com/news/2013-09-colorectal-cancer-screening.html
Colorectal cancer screening works
Perceptions of personal susceptibility to, and perceived severity of the disease, belief in ones ability to undertake a preventive action (perceived self-efficacy), the potential benefits of, and perceived barriers to undertaking this behaviour, all influence an individuals decision to partake in a preventive action. Attitudes are also influenced by demographic and other structural or socio-psychological factors. This model purports that a cue to action must occur to trigger a behavioural change; this may result from a doctors recommendation, media advertisement or an intervention. Several studies have used health belief theories to understand and identify factors associated with screening compliance [ 28 – 31 ]. By taking a similar approach, this study aimed to elucidate factors that may be associated with CRC screening intention. We present findings from a baseline survey that was conducted as part of an intervention study to assess the current knowledge, attitudes and behavioural intentions of Indigenous Western Australians in relation to bowel cancer and screening with FOBT. This information is critical for identifying specific areas for intervention, and focus for health promotion and education, to improve uptake of CRC screening and reduce disparities in bowel cancer outcomes for Indigenous Australians. Methods Study participants and data collection Participants were recruited from two regional and one metropolitan site in Western Australia through community and family networks of health professionals known to the researchers. Recruitment occurred between November 2009-March 2010 with assistance from Aboriginal staff employed in Aboriginal-specific health services. Eligibility criteria included self-identification as Aboriginal or Torres Strait Islander, aged 35 years or more, and the provision of written informed consent prior to participation. Questionnaires were administered at face-to-face interviews and participants received $20 to compensate for time and travel expenses. An Indigenous reference group assisted with all aspects of the study. The Western Australian Aboriginal Human Information and Ethics Committee (250 08/09) and the Curtin University Research Ethics Committee (CIH 11-2009) approved the study. Questionnaire Survey development The questionnaire measured respondents knowledge, attitudes, beliefs and behaviours related to the prevention, early detection and treatment of bowel cancer. The instrument was adapted and further developed from surveys identified in relevant literature, as no existing validated questionnaire was found that examined these elements in Indigenous Australians for any cancer screening modality.