The effect of information about the benefits and harms of mammography on women’s decision-making: study protocol for a randomized controlled trial

Abstract

BackgroundThe decision to participate or not in breast cancer screening is complex due to the trade-off between the expected benefit of breast cancer mortality reduction and the major harm of overdiagnosis. It seems ethically necessary to inform women so that they can actively participate in decision-making and make an informed choice based on their values and preferences.The objective of this study is to assess the effects of receiving information about the benefits and harms of screening on decision-making, in women approaching the age of invitation to mammography screening.MethodsA two-stage, randomized controlled trial (RCT). In the first stage, 40 Basic Health Areas (BHAs) will be selected and randomized to intervention or control. In the second stage, women within each BHA will be randomly selected (n = 400). Four breast cancer screening programs (BCSPs) of the Spanish public health system, three in Catalonia and one in the Canary Islands will participate in the study. Women in the intervention arm will receive a leaflet with detailed information on the benefits and harms of screening using mammography. Women in the control arm will receive a standard leaflet that does not mention harms and recommends accepting the invitation to participate in the biennial examinations of the BCSP.The primary outcome is informed choice, a dichotomous variable that combines knowledge, attitudes, and intentions. Secondary outcomes include decisional conflict; confidence in the decision made; anxiety about screening participation; worry about breast cancer; anticipated regret; time perspective; perceived importance of benefits/harms of screening; perceived risk of breast cancer; and leaflet acceptability. Primary and secondary outcomes are assessed 2–3 weeks after the intervention.DiscussionThis is the first RCT that assesses the effect of informing about the benefits and harms of breast cancer screening in Spain in women facing the decision to be screened using mammography. It aims to assess the impact of information on several decisional outcomes and to contribute to paving the road towards shared decision-making in breast cancer screening in our country.Trial registrationClinicalTrials.gov registry, ID: NCT03046004. Retrospectively registered on 4 February 2017. Trial name: InforMa study.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-017-2161-7) contains supplementary material, which is available to authorized users.

Effect of information about the benefits and harms of mammography on women’s decision making: The InforMa randomised controlled trial

“…The study was designed as a parallel two-stage randomised 1:1 controlled trial (RCT). In the first stage, elementary territorial units of the healthcare system named Basic Health Areas (BHAs) were stratified by socioeconomic level [14] and 40 of them were selected and randomised to intervention or control using computer-generated blocks of size two. In the second stage, random samples of 30 to 50 women within each BHA were obtained.…”

“…The study was approved by the Ethics Committees of the Arnau de Vilanova University Hospital in Lleida (approval number 19/2014), Parc de Salut Mar in Barcelona (2014/5998/I), Bellvitge University Hospital in Hospitalet (PR349/14), and by the Scientific and Ethics Committee of Nuestra Señora de la Candelaria University Hospital in Tenerife (Canary Islands, Spain). The published protocol describes with detail the study design and methods [14] (the trial study protocol approved by the Ethics Committee are included in S1 and S2 Files). The InforMa study was registered with the ClinicalTrials.gov registry, number NCT03046004.…”

“…Secondary outcomes (eg, decisional conflict, worry about breast cancer, time perspective, opinions about the DA, and participation in the BCSP) have been fully detailed in the protocol [14]. Decision conflict was assessed using the Decisional Conflict Scale (10-item low literacy version) by O’Connor [24, 25].…”

“…We performed the statistical analysis as planned in the protocol [14]. Primary and secondary outcomes in the two study groups were compared using the chi-square test for categorical variables and the Student’s t for quantitative variables.…”

Validación del instrumento Informed Choice para medir la decisión informada de mamografía en mujeres chilenas usuarias de atención primaria

“…Su disponibilidad en idioma español posibilita su uso en otros países de la región y de la comunidad hispanoparlante, contribuyendo al área de la detección temprana del cáncer de mama, prioridad en el control de cáncer y sus inequidades asociadas a nivel local y global 17 . Contar con un instrumento adaptado lingüística y culturalmente y validado en sus propiedades psicométricas 18 es fundamental tanto para la evaluación diagnóstica del proceso de toma de decisiones para el cribado de cáncer de mama, como para la evaluación de intervenciones que apunten a promover una decisión informada con relación a este examen 19 .…”