Population screening for colorectal cancer: the implications of an ageing population

Population screening for colorectal cancer (CRC) has recently commenced in the United Kingdom supported by the evidence of a number of randomised trials and pilot studies. Certain factors are known to influence screening cost-effectiveness (e.g. compliance), but it remains unclear whether an ageing population (i.e. demographic change) might also have an effect. The aim of this study was to simulate a population-based screening setting using a Markov model and assess the effect of increasing life expectancy on CRC screening cost-effectiveness. A Markov model was constructed that aimed, using a cohort simulation, to estimate the cost-effectiveness of CRC screening in an England and Wales population for two timescales: 2003 (early cohort) and 2033 (late cohort). Four model outcomes were calculated; screened and non-screened cohorts in 2003 and 2033. The screened cohort of men and women aged 60 years were offered biennial unhydrated faecal occult blood testing until the age of 69 years. Life expectancy was assumed to increase by 2.5 years per decade. There were 407 552 fewer people entering the model in the 2033 model due to a lower birth cohort, and population screening saw 30 345 fewer CRC-related deaths over the 50 years of the model. Screening the 2033 cohort cost £96 million with cost savings of £43 million in terms of detection and treatment and £28 million in palliative care costs. After 30 years of follow-up, the cost per life year saved was £1544. An identical screening programme in an early cohort (2003) saw a cost per life year saved of £1651. Population screening for CRC is costly but enables cost savings in certain areas and a considerable reduction in mortality from CRC. This Markov simulation suggests that the cost-effectiveness of population screening for CRC in the United Kingdom may actually be improved by rising life expectancies

Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.

Peer reviewedPublisher PD

Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation

NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αβ and γδ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1–6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12–US21; a genetic arrangement, which is suggestive of an ‘accordion’ expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family

Information needs and preferences of low and high literacy consumers for decisions about colorectal cancer screening: utilizing a linguistic model

Context The use of written decision aids (DAs) in clinical practice has proliferated. However, few DAs have been developed for low literacy users, despite this group having low knowledge about healthcare and lacking involvement in health decisions. Objective To explore the information needs and understanding of adults with varying literacy in relation to colorectal cancer screening, and to consider their responses to two versions of a decision aid. Participants Thirty-three men and women aged 45-74 years were recruited from Adult Basic Education classes (n = 17) and University Continuing Education programs (n = 16). Methods We used qualitative methods (in-depth, semi-structured interviews) to compare and contrast the views of adults with lower and higher literacy levels, to gain a better understanding of how people with lower literacy value and interpret specific DA content and components; and determine whether needs and preferences are specific to lower literacy groups or generic across the broad literacy spectrum. Results Regardless of literacy perspective, participants' interpretations of the DA were shaped by their prior knowledge and expectations, as well as their values and preferences. This influenced perceptions of the DAs role in supporting informed decision making. A linguistic theoretical model was applied to interpret the findings. This facilitated considerations beyond the traditional focus on the readability of materials. Conclusion Decision aids developers may find it useful to apply alternative approaches (linguistic) when creating DAs for consumers of varying literacy

Knowledge, Attitude and Intentions Related to Colorectal Cancer Screening Using Faecal Occult Blood Tests in a Rural Australian Population

A telephone survey with 604 men and women without history of colorectal cancer (CRC)(age 50-74 years) explored knowledge of, attitudes toward, and intention to screen for CRC using faecal occult blood tests (FOBT) in a rural Australian population. Overall, 53% intended to participate in and 86% would follow a doctor's recommendation for FOBT screening. In contrast, only 18% had ever had a FOBT, and fewer than 60% of those with high-risk family history had undergone appropriate screening for CRC. Prior use of FOBT (OR=3.2), high perceived susceptibility to CRC (OR=2.4), belief in the importance of screening despite the absence of symptoms (OR=2.1) were positively and older age (OR = 0.5) was negatively related to screening intention in multivariate logistic regression analysis. A doctor's recommendation improved screening intention among those who never tested for CRC before but believe in the importance of early treatment. This study highlights the lack of compliance with standard CRC screening recommendations in Australia and provides evidence for the importance of continued educational efforts, with the particular emphasis on older adults and the medical community