Table 2 Summary of BOOST pACP program according to the Template intervention description and replication (TiDieR) checklist

1.

BRIEF NAME (name or a phrase that describes the intervention)

BOOST pACP (Benefits of Obtaining Ownership Systematically Together in paediatric advance care planning) program

2.

WHY (any rationale, theory, or goal of the elements essential to the intervention)

A more positive attitude and improved self-efficacy towards communicating about ACP themes between adolescents and their parent(s) may result in an intention to talk more about ACP themes. This in turn may lead to improved parent-adolescent communication.

3.

WHAT Materials (any physical or informational materials used in the intervention, including those provided to participants or used in intervention delivery or in training of intervention providers)

The BOOST pACP program includes 8 supporting materials:

1. Training program and accompanying PowerPoint presentations used for the 2.5-day training of the ACP facilitators

2. A manual for trained ACP facilitators who will perform the ACP conversations with adolescents and parent(s), including a description of steps to follow during and between the structured ACP conversation sessions.

3. Preparation booklets for both the adolescent and parent(s), including information about the program, why ACP is relevant and questions to trigger the thinking process about ACP themes.

4. A video in which two families talk about their personal situation and experienced effects of the ACP program.

5. Conversation cards to structure the ACP conversation sessions with the adolescent covering the following ACP themes: 1) Who am I?; 2) How do I experience my illness? 3) Talking with others; 4) Help and comfort; 5) Worries and fears; 6) What care do you want?; 7) Expectations for the future; 8) About dying. Adolescents are asked to divide the themes into two categories: “I would like to talk about this theme with my parent(s)” and “at the moment I do not feel the need to talk about this theme with my parent(s)”

6. Conversation cards to structure the ACP conversation session with parent(s) covering the following ACP themes: 1) Talking with your child; 2) Parenthood; 3) Help and comfort; 4) Worries and fears; 5) Care and treatment; 6) Expectations for the future; 7) About dying

7. A summary sheet that will be filled out by the parent(s) and adolescent together in session 3 to stimulate conversation about ACP themes.

8. Conversation cards that can be used as a game of quartet at home. Families will receive these cards at the end of session 3.

4.

WHAT Procedures (each of the procedures, activities, and/or processes used in the intervention, including any enabling or support activities)

The BOOST program entails 10 program components that can be carried out via 17 activities:

As part of “Facilitator training (including manual)” component (1)

Activity 1: Selection of two external facilitators

Activity 2: Preparation of facilitators for the training

Activity 3: Two-and-a-half-day training program for facilitators

Activity 4: Intervision sessions (discussing challenges in case studies) approximately every 4 months for facilitators (2–5 h)

As part of “Preparation booklets” component (2)

Activity 5: Data collectors give preparation booklets to the families that are assigned to the intervention group

Activity 6: Adolescent and parent(s) read their preparation booklet before conversation session 1 takes place

As part of “Video” component (3)

Activity 7: The facilitator introduces the videos that will be shown in conversation session 1.

Activity 8: Adolescent and parent(s) watch the video during conversation session 1.

Activity 9: The facilitator asks whether the adolescent and parent(s) recognize any aspect from the video.

As part of “Conversation session 1” (4)

Activity 10: The facilitator guides the conversation session and introduces the conversation cards to the adolescent and parent(s):

As part of “Conversation session 2a” (5)

Activity 11: The facilitator guides the conversation session with the adolescent alone and uses conversation cards to discuss ACP themes.

As part of “Conversation session 2b” (6)

Activity 12: The facilitator guides the conversation session with the parent(s) alone and uses conversation cards to discuss ACP themes.

As part of “Conversation session 3” (7)

Activity 13: The facilitator guides the conversation session with the adolescent and parent(s) and allows them to discuss ACP themes.

As part of “Summary sheet” (8)

Activity 14: The facilitator introduces and explains the summary sheet. The facilitator asks whether the family would like the information they write down to be shared with the paediatric oncologist.

As part of “Conversation cards that can be used as a game of quartet at home” (9)

Activity 15: The facilitator explains the purpose of the quartet game and that the cards can facilitate communicating on ACP themes together at home in a playful way.

As part of “Transfer of information to a treating paediatric oncologist” (10)

Activity 16: In case the family gave permission, the facilitator makes an appointment with the paediatric oncologist that the family indicated.

Activity 17: The facilitator gives a summary of the conversations with the family to the paediatric oncologist and asks whether the paediatric oncologist can add the summary sheet to the electronic dossier of the patient.

5.

WHO PROVIDED (intervention provider, their expertise, background and any specific training given)

External facilitators are hired by the research team to perform the BOOST pACP program, more specifically to facilitate the structured ACP conversations with the families. Facilitators (psychologists) will receive a 2.5 day training and ongoing 4-monthly intervision to respond to different scenarios and situations (such as strategies when there is little response, dealing with resistance, and emotional feelings of the participants).

6.

HOW (modes of delivery)

All ACP conversation sessions are provided face-to-face (at home or at the hospital) or online by video call, depending on the family’s preference. The transfer of information with the paediatric oncologist/ medical team will take place by (video) call or in real life.

7.

WHERE (the type(s) of location(s) where the intervention occurred, including any necessary infrastructure or relevant features)

The conversation sessions can take place either at the home address of the family, in the hospital or online by video call (because of the COVID-19 measures).

8.

WHEN and HOW MUCH (the number of times the intervention was delivered and over what period of time including the number of sessions, their schedule, and their duration, intensity or dose)

The intervention period per family is three months (from receiving the preparation booklets to the transfer of information with the paediatric oncologist). Each conversation session will take approximately 60 min. There will be at least one week in between the conversation sessions, due to the importance of time to reflect on ACP themes and potentially discuss certain ACP themes at home if participants want to. The intervision sessions for the facilitators will take maximally five hours and will be planned every 4 months.

9.

TAILORING (if the intervention was planned to be personalized, titrated or adapted, then describe what, why, when, and how)

Within the conversation sessions, participants have freedom and flexibility in choosing certain ACP themes to discuss and the facilitator will clarify that participants are not obligated to talk about all ACP themes. The conversation sessions are structured in the sense that per topic, there is a key question and two follow-up questions that will be asked always. Apart from that, facilitators can ask other questions or decide to zoom in on the participant’s story whenever they want.

Families can choose the mode of delivery of the conversation sessions (face-to-face at home or in the hospital or online by video call). Furthermore, the facilitator will ask paediatric oncologists how they would like to organize the transfer of information (if family permitted sharing a summary of the conversations with healthcare professionals).

10

FIDELITY - HOW WELL (planned)

As part of the process evaluation, we will record audio recordings of all structured ACP sessions 1, 2a, 2b and 3 from eight dyads in total (after consent) to evaluate fidelity. We will use a fidelity checklist that is based on the steps described in the manual of the facilitators.