Abstract
Objectives
Participation in screening should be the outcome of an informed decision. We evaluated whether invitees in the first Dutch colorectal cancer (CRC) screening programme were adequately informed after having received a detailed information leaflet.
Methods
A total of 20,623 subjects aged 50–75 years were invited to the fecal occult blood test (FOBT) screening programme. All received a detailed information leaflet by mail between May 2006 and January 2007. After two weeks, a reminder letter was sent to all invitees, accompanied by a survey on CRC and screening.
Results
The survey was completed by 9594 invitees (47%). Almost all responders (99%) found the leaflet clear and readable. Almost all indicated that CRC can be treated better if found early (99%). Only 20% of the responders answered all knowledge-related answers correctly. Almost half of the responders (47%) believed that a negative FOBT excludes the presence of CRC. Older age and having a positive family member for CRC were correctly identified as risk factors by 80%.
Conclusion
This study demonstrates that although an information leaflet was reported as being clear and readable, the information provided in it was not always understood well. This suggests that other educational options should be investigated in order to improve general knowledge of CRC in screening invitees.
INTRODUCTION
Colorectal cancer (CRC) has a known high incidence in the western world and it is predicted that the incidence will increase in the future. 1–4 CRC is known to have a long asymptomatic phase, which makes early detection difficult, while early lesions are far better treatable and lead to better prognoses. 5,6 Many countries have now initiated population-based screening programmes. An important dilemma in screening for CRC is the relatively low participation rate compared with screening programmes for breast cancer or cervical cancer. 7–11
There are multiple possible reasons for low participation. For this study we focused on knowledge as an important factor for low participation. In order to participate in a screening programme, invitees should be provided with adequate information. For an individual to make an informed choice to participate in or decline screening, the potential benefits, limitations and consequences of screening should be clearly communicated. 12 Previous research has shown that high levels of knowledge are positively associated with participation and that a common reason for non-participation in a screening programme is lack of awareness. 13,14 An earlier study reported low levels of knowledge throughout Europe and especially in the Netherlands. 15 Proper education, particularly through patient decision aids, may contribute to a better understanding of CRC. 16
For the first screening programme in the Netherlands a detailed information leaflet was developed, providing information for all the screening invitees. The leaflet contained information on CRC and on the benefits and consequences of screening. This study was undertaken to evaluate whether participants of the CRC screening programme were adequately informed after having received the detailed information leaflet.
METHODS
A total of 20,623 subjects aged 50–75 years were invited to the first Dutch CRC screening programme between May 2006 and January 2007 from two regions in the Netherlands (Amsterdam and Nijmegen) representative of the average Dutch population. Detailed information and the results of this randomized study are reported elsewhere. 17 A screening package was sent by mail to all those invited for screening. The package consisted of an information leaflet, an invitation letter and a fecal occult blood test (FOBT).
The 18-page leaflet contained detailed information on CRC screening and the offered screening test. Table 1 provides translated excerpts from the leaflet on specific issues. The information provided in the leaflet was similar to leaflets designed of other European screening trials. The primary messages highlighted in the leaflet were the screening programme itself, the purpose, benefits and limitations of screening, the risk factors associated with CRC, and instructions on how to use the FOBT. A linguistic expert was involved to make the leaflet clear and readable for the level of understanding in an average Dutch population. The leaflet was provided in the Dutch language only.
Overview of the information given in the leaflet and the questions asked two weeks after the initial invitation
Academic Medical Centre, University of Amsterdam, the Netherlands. First Dutch colorectal cancer (CRC) screening programme performed between May 2006 and January 2007
*The information as provided verbatim in the leaflet translated from Dutch
The leaflet emphasized that participants with bowel complaints or recent rectal blood loss should consult their general practitioner and were advised not to perform the FOBT.
Two weeks after the initial invitation a reminder letter was sent. The reminder letter was accompanied by a two-page survey. This survey contained 36 statements designed for this screening programme. For the development of the survey, a qualitative interview took place to learn more about the views of potential screening invitees. A total of 32 individuals aged between 52 and 73 years completed a 20-minute interview, in which issues regarding screening, CRC and the FOBT were explored. The interviews were recorded, fully transcribed and entered into a database. A number of items were identified by the literature search and the interviews and corresponded with the information provided in the leaflet. These statements were converted into statements for the survey. The invitee could fill in to either ‘agree’ or ‘not agree’ with each the statement or fill in ‘not applicable’.
In this analysis, we only include items in the survey related to knowledge about CRC and CRC screening. The analysis included one self-reported knowledge item, four knowledge-related items and three advice-related statements. The definition of ‘adequate knowledge’ for this study was defined as being able to answer the knowledge-related statements of the survey correctly (Table 1). All data collected were analyzed with SPSS version 14.0.2 (SPSS Inc, Chicago, IL, USA).
RESULTS
The overall participation rate for the FOBT screening was 53% (n = 10,993). The survey was completed by 9594 invitees (47%). Of these 9594 survey responders, a total of 8989 also returned their FOBT (94%). The mean age of responders was 62 years and 45% were men.
Almost all responders (99%) reported that they had understood the information leaflet as clear and readable. Table 1 contains the knowledge-related and advice-related items of the survey, the number of responses and the number of positive and negative answers.
The self-reported statement on knowledge resulted in 61% that stated they knew little about CRC as a disease. To test adequate knowledge we analysed how many individuals answered the four knowledge-related answers correctly (Table 1). Twenty percent of the responders answered all knowledge-related answers correctly. Eighty-seven percent answered three out of four statements correctly and 61% answered a minimum of two out of four statements correctly.
Most of the participants correctly answered that CRC can be treated better if found early (99%). Of all responders, 47% believed that a negative FOBT (no blood in the stool) excludes the presence of CRC. Age older than 50 years was correctly identified as a risk factor for CRC by 6278 of the responders (79%). A positive family history was also correctly identified as a risk factor by 6159 (80%). Of the 295 responders with a first-degree family member with CRC, 221 (75%) acknowledged that they had an increased risk for CRC.
The leaflet recommended invitees not to perform the FOBT in case of complaints, but to consult their general practitioner. Of all responders who reported a recent change in bowel habits (n = 1500) or rectal blood loss (n = 685), only 44 responders (2%) had consulted their general practitioner and almost all these invitees (96%), returned the FOBT in contrast with the advice.
DISCUSSION
In this study, 99% of the responders reported that the information in the leaflet provided in this screening programme was clear and readable. It can be reasonably expected that because almost all responders of the survey found the leaflet clear and readable they also read the leaflet. Only 20% of the responders answered all knowledge-related answers correctly. Most of these participants answered correctly that CRC is better treatable if found early, an observation that corresponds well with the fact that most (94%) in this study also participated in this FOBT screening programme. Nevertheless, a disturbing high proportion (47%) believed that a negative FOBT excluded the possibility of having CRC. The fact the FOBT detects only blood, and not cancer, increasing the likelihood of CRC, is apparently a difficult message. Poor understanding of the FOBT could be harmful. A false-negative result may convey in a false sense of health, which could lead to a delayed diagnosis of an underlying adenoma or early cancer. Reassurance of people with negative FOBT results may make them more resistant to general health recommendations because they interpret the test result from screening as showing that they are immune to the impact of unhealthy lifestyles: a phenomenon described as the ‘certificate of health’ effect. 18
A limitation of this study is that there is no general agreement on the definition of being adequately informed. 19 For this study, we focused on the level of knowledge and measured this by being able to answer four knowledge-related statements correctly. We cannot exclude that participants were able to verify the answers in the information leaflet or guessed the right answer. This could have generated an overestimation of correctly given answers. It is thus possible that the true number of responders understanding the meaning of these statements is even lower.
This study also showed that only a few responders adhered to the recommendation in the leaflet not to perform the FOBT and to consult their general practitioner in case of rectal blood loss. This may also point to a misinterpretation of the significance of the test result. However, it is also possible that other reasons may have been of influence, e.g. lack of time to consult a general practitioner.
CONCLUSION
Among those who returned the questionnaire, most of whom were individuals invited for a screening programme, there was misunderstanding about the fact that screening is for asymptomatic people and that there are limitations to the accuracy of FOBT, despite this information being provided within the information leaflet. Providing an information leaflet is not enough to communicate the benefits and harms of screening to those invited to a population based screening programme. Literature has shown that intensifying and extending the method of information supply for a FOBT screening programme contributes to higher levels of knowledge. 20,21 A recently published randomized trial also found that detailed risk and benefit information about FOBT screening contributes higher levels of informed choice. 22 A high participation rate should not be interpreted as proof of well-informed decision-making. We believe that our findings should encourage us and others responsible for screening to find better ways of informing screening invitees.
Footnotes
ACKNOWLEDGEMENTS
The authors thank the Comprehensive Cancer Centre Amsterdam and Kirsten McCaffery for their contributions to the study.