Roon, A.H.C. van

Cost-effectiveness of one versus two sample faecal immunochemical testing for colorectal cancer screening (Article)

2013-05-01T00:00:00Z

Objective The sensitivity and specificity of a single faecal immunochemical test (FIT) are limited. The performance of FIT screening can be improved by increasing the screening frequency or by providing more than one sample in each screening round. This study aimed to evaluate if two-sample FIT screening is cost-effective compared with one-sample FIT. Design The MISCANecolon microsimulation model was used to estimate costs and benefits of strategies with either one or two-sample FIT screening. The FIT cut-off level varied between 50 and 200 ng haemoglobin/ml, and the screening schedule was varied with respect to age range and interval. In addition, different definitions for positivity of the two-sample FIT were considered: at least one positive sample, two positive samples, or the mean of both samples being positive. Results Within an exemplary screening strategy, biennial FIT from the age of 55-75 years, one-sample FIT provided 76.0-97.0 life-years gained (LYG) per 1000 individuals, at a cost of $259000-264000 (range reflects different FIT cut-off levels). Two-sample FIT screening with at least one sample being positive provided 7.3-12.4 additional LYG compared with one-sample FIT at an extra cost of $50000-59 000. However, when all screening intervals and age ranges were considered, intensifying screening with one-sample FIT provided equal or more LYG at lower costs compared with two-sample FIT. Conclusion If attendance to screening does not differ between strategies it is recommended to increase the number of screening rounds with one-sample FIT screening, before considering increasing the number of FIT samples provided per screening round.

What influences the decision to participate in colorectal cancer screening with faecal occult blood testing and sigmoidoscopy? (Article)

2013-04-08T00:00:00Z

Introduction: Uptake is an important determinant of the effectiveness of population-based screening. Uptake of colorectal cancer (CRC) screening generally remains sub-optimal. Aim: To determine factors influencing the decision whether to participate or not among individuals invited for faecal occult blood test (FOBT) or flexible sigmoidoscopy (FS) screening. Methods: A questionnaire was sent to a stratified random sample of individuals aged 50-74, previously invited for a randomised CRC screening trial offering FOBT or FS, and a reference group from the same population not previously invited (screening naïve group). The questionnaire assessed reasons for (non)-participation, individuals' characteristics associated with participation, knowledge, attitudes and level of informed choice. Results: The response rate was 75% (n = 341/452) for CRC screening participants, 21% (n = 676/3212) for non-participants and 38% (n = 192/500) for screening-naïve individuals. The main reasons for FOBT and FS participation were acquiring certainty about CRC presence and possible early CRC detection. Anticipated regret and positive attitudes towards CRC screening were strong predictors of actual participation and intention to participate in a next round. The main reason for non-participation in FOBT screening was lack of abdominal complaints. Non-participation in FS screening was additionally influenced by worries about burden. Eighty-one percent of participants and 12% of non-participants made an informed choice on participation. Conclusion: Only 12% of non-participants made an informed choice not to participate. These results imply that governments and/or organizations offering screening should focus on adequately informing and educating target populations about the harms and benefits of CRC screening. This may impact uptake of CRC screening.

Colorectal Cancer Screening by Means of Faecal Immunochemical Testing (FIT) (Doctoral Thesis)

2012-04-18T00:00:00Z

The term ‘screening’ is derived from the verb ‘to screen’ and means ‘to guard’ or ‘to filter’. The aim of a nationwide screening programme is to ‘filter’ an in principle healthy population in order to detect those with a disease or condition at an early stage, before the occurrence of any signs or symptoms. Actively looking for the early stages of a disease or condition is classified as secondary prevention. Additionally, primary prevention strategies intend to avoid the development of the disease and tertiary prevention aims to reduce the negative impact of established disease by restoring function and reducing disease-related complications. The development of a malignancy is a multistep process: at some point in time the first cancer cells develop and will start to divide in an uncontrolled way ultimately resulting in a tumour. Growth is local at first but then continues into the surrounding tissues and eventually metastasizes, ultimately leading to the individuals’ death. At some stage during this process, the individual generally seeks medical advice for their newly-developed symptoms. Subsequently, further investigations are carried out and the diagnosis of ‘cancer’ is made. Between the start of the uncontrolled division of the first cancer cells and manifestation of symptoms, there may be a moment at which the tumour is large enough to be detected by a screening test. The aim of screening is therefore to bring forward the time of diagnosis before the stage at which the first signs and symptoms of the disease come to light, the so-called lead time. Detection at an early stage is associated with less intensive treatment and a better outcome. Depending on the disease and test characteristics, screening may in some instances also detect the premalignant lesions that manifest themselves prior to the invasive stage.

Are fecal immunochemical test characteristics influenced by sample return time a population-based colorectal cancer screening trial (Article)

2012-01-01T00:00:00Z

Objectives: Fecal immunochemical tests (FIT) are preferred over guaiac-based fecal occult blood testing as colorectal cancer (CRC) screening tool. However, hemoglobin (Hb) degradation over time may influence FIT outcome. We therefore evaluated the effect of sample return time on FIT performance characteristics in a population-based CRC screening trial. Methods: A representative random sample of the Dutch population (n=17,677), aged 50-74 years, was invited for FIT screening (OC-Sensor Micro; cutoff 50 ng Hb/ml). Sample return time was defined as the interval in days between fecal sampling and FIT laboratory delivery. Moreover, a random sample of positive FITs were selected to be stored at room temperature and re-tested every 3-4 days. Results: In total, 8,958 screenees fulfilled our inclusion criteria. The mean sample return time was 3 days (±3). Overall, 792 screenees (8.8%) had a positive test. Between the sample return time groups, the positivity rate (PR) varied between 7.7 and 9.0%. No statistically significant associations were found between PR or detection rate (DR) and the different sample return time groups (P value=0.84 and 0.76, respectively). For the laboratory experiment, 71 positive FITs were stored at room temperature and re-tested with standard intervals. The mean daily fecal Hb decrease was 5.88% per day (95% confidence interval 4.78-6.96%). None of the positive FITs became negative before 10 days after fecal sampling. Conclusions: This population-based CRC screening trial demonstrates that both the PR and DR of FITs do not decrease with prolonged sample return times up to 10 days. This means that a delay in sending the FIT back to the laboratory, of up to at least 1 week, does not necessitate repeat sampling in case of a negative test result. These data support the use of FIT-based screening as a reliable tool for nationwide CRC screening programs.

Advance notification letters increase adherence in colorectal cancer screening: A population-based randomized trial (Article)

2011-06-01T00:00:00Z

Objective: The population benefit of screening depends not only on the effectiveness of the test, but also on adherence, which, for colorectal cancer (CRC) screening remains low. An advance notification letter may increase adherence, however, no population-based randomized trials have been conducted to provide evidence of this. Method: In 2008, a representative sample of the Dutch population (aged 50-74. years) was randomized. All 2493 invitees in group A were sent an advance notification letter, followed two weeks later by a standard invitation. The 2507 invitees in group B only received the standard invitation. Non-respondents in both groups were sent a reminder 6. weeks after the invitation. Results: The advance notification letters resulted in a significantly higher adherence (64.4% versus 61.1%, p-value 0.019). Multivariate logistic regression analysis showed no significant interactions between group and age, sex, or socio-economic status. Cost analysis showed that the incremental cost per additional detected advanced neoplasia due to sending an advance notification letter was €957. Conclusion: This population-based randomized trial demonstrates that sending an advance notification letter significantly increases adherence by 3.3%. The incremental cost per additional detected advanced neoplasia is acceptable. We therefore recommend that such letters are incorporated within the standard CRC-screening invitation process.

Diagnostic Yield Improves With Collection of 2 Samples in Fecal Immunochemical Test Screening Without Affecting Attendance (Article)

2011-04-01T00:00:00Z

Background & Aims: The fecal immunochemical test (FIT) is superior to the guaiac-based fecal occult blood test in detecting neoplasia. There are not much data on the optimal number of FITs to perform. We conducted a population-based trial to determine attendance and diagnostic yield of 1- and 2-sample FIT screening. Methods: The study included 2 randomly selected groups of subjects aged 50-74 years (1-sample FIT, n = 5007; 2-sample FIT, n = 3197). The 2-sample group was instructed to collect fecal samples on 2 consecutive days. Subjects were referred for colonoscopy when at least 1 sample tested positive (≥50 ng hemoglobin/mL). Results: Attendance was 61.5% in the 1-sample group (2979 of 4845; 95% confidence interval, 60.1%-62.9%) and 61.3% in the 2-sample group (1875 of 3061; 95% confidence interval, 59.6%-63.0%; P = .84). In the 1-sample group 8.1% tested positive, and in the 2-sample group 12.8% had at least 1 positive test outcome and 5.0% had 2 positive test outcomes (P < .05). When the mean from both test results in the 2-sample group was used, 10.1% had a positive test outcome (P < .05). The detection rates for advanced neoplasia were 3.1% in the 1-sample group, 4.1% in the 2-sample group with at least 1 positive test outcome, 2.5% when both test results were positive, and 3.7% among subjects with the mean from both test results being positive. Conclusions: There is no difference in attendance for subjects offered 1- or 2-sample FIT screening. The results allow for the development of efficient FIT screening strategies that can be adapted for local colonoscopy capacities, rather than varying the cut-off value in a 1-sample strategy.

Immunochemical fecal occult blood test in a screening program for colorectal cancer [De immunochemische fecaaloccultbloedtest in een screeningsstudie naar colorectaal carcinoom] (Article)

2010-01-01T00:00:00Z

The Health Council of the Netherlands advised on a national screening program for colorectal cancer (CRC) in November last year. Studies have already shown that screening for CRC using the guaiac based fecal occult blood test (gFOBT) reduces mortality, and more recently, results have been published using the immunological FOBT (iFOBT). The gFOBT and iFOBT do not differ in their CRC-detection rate, however, more advanced adenomas are found using the iFOBT. While the iFOBT is a quantitative test, it offers the possibility of choosing different cut-off points. It appears that, both clinical and analytical, a cut-off point of 75 ng/ml can be used, if adequate capacity for colonoscopy is available.