Adherence to adjuvant endocrine therapy in women with breast cancer is low. We conducted a 24-1 fractional factorial pilot optimization trial to test four intervention components supporting medication adherence [text messages, information leaflet, acceptance and commitment therapy (ACT), self-management website], in the preparation phase of the multiphase optimization strategy. Guided by the National Institute of Health Behavior Change Consortium fidelity framework, we investigated fidelity of design, training, delivery, receipt, and enactment of four intervention components. Women prescribed adjuvant endocrine therapy (n = 52) were randomized to one of eight experimental conditions comprised of combinations of the four intervention components (ISRCTN: 10487576). We assessed fidelity using self-report data (4 months post-randomization), trial data, ACT session observations, behavior change technique (BCT) coding, and interviews with participants (n = 20) and therapists (n = 6). Design: Each intervention component targeted unique behavior change techniques with some overlap. Training: All 10 therapists passed the competency assessment. Delivery: All leaflets (27/27) and website (26/26) details were sent, and ACT procedural fidelity was high (85.1%-94.3%). A median of 32.5/41 (range 11-41) text messages were delivered, but a system error prevented some messages being sent to 22 of 28 participants. Receipt: Most participants [63.0% (ACT, leaflet) to 71.4% (text messages)] read all or at least some of the intervention components they were randomized to receive. Enactment was reported most positively for ACT. All intervention components demonstrated adequate fidelity. We have provided an exemplar for assessing fidelity using the National Institute of Health Behavior Change Consortium framework in the preparation phase of multiphase optimization strategy.
Keywords: breast cancer; intervention fidelity; medication adherence; multiphase optimization strategy; optimization trial; process evaluation.
Most women with breast cancer are recommended hormone therapy. However, many women do not take it as prescribed. We developed four support programs consisting of text messages, an information leaflet, a therapy program, and a side-effect management website. Fifty-two women prescribed hormone therapy were allocated to receive different combinations of the support. Women completed a questionnaire after 4 months, and we looked at data from the study to assess whether the support was delivered and received as planned (fidelity). We also interviewed therapists and participants. We found that each type of support was distinct, with some overlap. The therapists could all deliver the therapy appropriately. Most of the support was delivered as planned, but a system error stopped some text messages from being sent. Most participants said they read “at least some of” or “all of” the support materials they were given. Participants spoke about using the therapy most often. Overall, we found that we could deliver the four types of support as planned. We will use the results to make improvements before running a larger trial to assess how effective each type of support is.
© The Author(s) 2024. Published by Oxford University Press on behalf of the Society of Behavioral Medicine.