Decision Support Tool for Patients With Advanced Breast Cancer

The proportion of patients who agree with the acceptability of the COAST decision support tool is measured by the Acceptability of Intervention Measure (AIM). This tool consists of four items designed to monitor and evaluate the success of implementation efforts. Respondents can rate each item on a scale from 1 (completely disagree) to 5 (completely agree). Higher scores reflect greater agreement with the acceptability of the intervention.

Patients with a score of 4 or higher will be included in the numerator, while all patients who complete the measure will be included in the denominator. We will define COAST as "acceptable" if this proportion is greater than 70%.

The proportion of patients who agree with the appropriateness of the COAST decision support tool is measured using the Intervention Appropriateness Measure (IAM). This tool consists of four items designed to evaluate the suitability and relevance of an intervention. Respondents can rate each item on a scale from 1 (completely disagree) to 5 (completely agree).

Higher scores reflect greater agreement with the appropriateness of the intervention.

Patients with a score of 4 or higher will be included in the numerator, while all patients who complete the measure will be included in the denominator. We will define COAST as "appropriate" if this proportion is greater than 70%.

The proportion of healthcare providers who care for adult patients with metastatic breast cancer (MBC) and agree on the feasibility of the COAST decision support tool is measured using the Feasibility of Intervention Measure (FIM). This tool consists of four items designed to measure the feasibility or extent to which an intervention can be successfully used or carried out within a given setting. Respondents can rate each item on a scale from 1 (completely disagree) to 5 (completely agree). Higher scores reflect greater agreement with the feasibility of implementing the COAST tool.

Providers with a score of 4 or higher will be included in the numerator, while all providers who complete the measure will be included in the denominator. We will define COAST as "feasible" if this proportion is 70% or greater.

Mean change from baseline in patient decisional conflict will be assessed via Decisional Conflict Scale (DCS), which includes 5 subscales (uncertainty, informed, values clarity, support, effective decision). Each item is rated on a scale of 0 (strongly agree) to 4 (strongly disagree). Scores range from 0-100 with higher scores indicating more decisional conflict.

Mean change from baseline in patient-centered communication score will be assessed via Patient-Centered Communication (PCC) in cancer care. The purpose of the measure is to assess PCC in six core domains: 1) exchanging information, 2) making decisions, 3) fostering healing relationships, 4) enabling patient self-management, 5) managing uncertainty, and 6) responding to emotions. Respondents can rate each item on a scale, where higher scores indicate better patient-centered communication and greater perceived support from the healthcare team.

Mean Change from Baseline in patient self-efficacy for making decisions will be assessed via the Decisional Self-Efficacy Scale. The Scale measures self-confidence or belief in one's abilities in decision making, including shared decision-making. Respondents can rate each item on a scale from 0 (not at all confident) to 4 (very confident). A score of 0 means "extremely low self-efficacy" and a score of 100 means "extremely high self-efficacy".