Condition category
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
Regular colorectal cancer (CRC) screening is recommended for people older than 50 years old because they have a higher risk of developing this disease. However, a significant proportion of this population do not comply with this recommendation. The researchers have developed a web-based decision aid (DA) to help people to make an informed decision about undergoing CRC screening. It includes information about the disease, as well as two screening procedures: fecal occult blood test (FOBT) and colonoscopy (their characteristics, potential benefits and harms). The DA is available on the following link: The aim of this study is to find out whether this DA can help people to make informed decisions about CRC screening.

Who can participate?
People between 50-69 years old who have no history of CRC or current symptoms, and who have never had been screened for CRC

What does the study involve?
Participants are randomly allocated to either individually review the DA accompanied by a researcher, or to not review the DA. The main outcome assessed is decisional conflict, that is, participants' uncertainty about undergoing CRC screening or not. The study also assesses their knowledge about CRC and the screening procedures, their intention to be screened, and the importance that they attributed to different characteristics of the screening procedures.

What are the possible benefits and risks of participating?
Regarding potential benefits, those allocated to the intervention group have access to evidence-based information about colorectal cancer screening. There are no risks of potential physical or psychological harm for participating in the trial.

Where is the study run from?
1. Primary care center of Santa Ursula (Tenerife)
2. Primary care center of Ofra (Tenerife)

When is the study starting and how long is it expected to run for?
January 2016 to March 2017

Who is funding the study?
Carlos III Health Institute (Spain)

Who is the main contact?
Amado Rivero-Santana

Trial website

Contact information



Primary contact

Mr Amado Rivero-Santana


Contact details

Camino Candelaria
El Chorrillo
El Rosario
Santa Cruz de Tenerife

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effectiveness of a decision aid for promoting colorectal cancer screening in Spain: a randomized trial


Study hypothesis

Reviewing a decision aid about colorectal cancer screening will improve participants' decisional conflict about undergoing the procedure.

Ethics approval

Scientific and Ethics Committee of the Hospital Universitario Nuestra Señora de la Candelaria (Tenerife, Spain), January 2016, file number: 2013/21

Study design

Interventional randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type


Patient information sheet


Colorectal cancer


The study took place in two primary care centers: one located in an area where a public screening program was available, and other in which that program was not available at the moment of the study.

Participants were randomly allocated to the intervention (web-based decision aid) or usual care. Computerized randomization was carried out centrally by an independent researcher. Allocation was not blinded for patients and researchers.

The decision aid (DA) included information about colorectal cancer and two screening procedures: fecal occult blood test (FOBT) and colonoscopy (their characteristics, potential benefits and harms). It is available on the following link:

Each intervention participant reviewed the DA accompanied by a researcher in her/his primary care center. Outcome measures were assessed by questionnaires immediately after reviewing the DA.

Participants in the control group did not review the DA and just completed the questionnaires assessing the outcome measures.

Intervention type



Drug names

Primary outcome measure

Decisional conflict, measured with the Decisional Conflict Scale (DCS) immediately after reviewing the DA in the intervention group, and at the baseline assessment in the control group

Secondary outcome measures

1. Knowledge of the disease and the screening procedures, assessed using 12 items questionnaire
2. Intention to undergo screening (yes/no)
3. Concordance between participants' values about the characteristics of the screening procedures (importance attributed in a 1-5 Likert scale) and their intention to be screened
All assessments were performed immediately after reviewing the DA in the intervention group (except for knowledge, which was also measured before the aplication of the DA), and at the baseline assessment in the control group

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Age 50-69
2. Having no CRC history or current symptoms
3. Having no family antecedents of CRC
4. Not been screened previously

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

Cognitive impairment that hinders understanding of the study aims, information provided in the DA, or filling out the questionnaires

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Primary care center of Santa Ursula (Tenerife)

Trial participating centre

Primary care center of Ofra (Tenerife)

Sponsor information


Carlos III Health Institute (Spanish Ministry of Economy, Industry and Competitiveness)

Sponsor details

C/ Sinesio Delgado
4 (entrada por Avda. Monforte de Lemos

Sponsor type




Funder type


Funder name

Instituto de Salud Carlos III

Alternative name(s)

Institute of Health Carlos III, Carlos III Health Institute, ISCIII

Funding Body Type

government organisation

Funding Body Subtype

National government



Results and Publications

Publication and dissemination plan

An article reporting the study results is currently under review in the journal BMC Medical Informatics and Decision Making.

IPD sharing statement
The datasets generated during and/or analysed during the current study are/will be available upon request from Lilisbeth Perestelo-Pérez ( The trialists will share all of the individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures and appendices). Other documents available: study protocol, statistical analysis plan, informed consent form, analytic code. The data will be available immediately following publication (no end date). The data will be available for researchers who provide a methodologically sound proposal to achieve aims in the approved proposal. Proposals should be directed to Dr Lilisbeth Perestelo-Perez ( To gain access, data requestors will need to sign a data access agreement.

Intention to publish date


Participant level data

Available on request

Basic results (scientific)

Publication list

2019 results in: (added 14/01/2019)

Publication citations

Additional files

Editorial Notes

16/07/2019: Total final enrolment added. 14/01/2019: Publication reference added.