Table 2 Measures of Secondary Outcomes, Sample Characteristics, and Baseline Covariates

QOL

Other dimensions of quality of life will be measured by the EORTC QLQ-C30 subscales (global QOL; physical, social, role, cognitive functioning; physical symptoms) [33].

Distress

The 21-item Depression Anxiety Stress Scale [37]. Assesses anxiety, depression and stress over the previous week; total distress score will be used.

The total scale score of the 17-item Post-traumatic Stress Scale-Self-Report (PSS-SR) will be used to measure cancer-specific distress [38]. Items measure symptoms experienced over the past week, rated on a 4-point scale (0 = not at all to 4 = almost always), and anchored to cancer diagnosis as the stressor. Higher scores indicate higher cancer-specific distress

Fear of Progression

The English-version of the 12-item Fear of Progression Questionnaire short form measures levels of anxiety regarding cancer progressing on a five-point Likert scale from 1 (‘never’) to 5 (‘very often’) [39].

Unmet needs

34-item Supportive Care Needs Survey – Short Form [40]. Measures perceived psychosocial, information, physical/activity of daily living, patient care and sexuality needs.

Cost utility

The EuroQol 5 dimensions 5 level (EQ-5D-5L) is a generic preference-based measure [41]. Based on Australian-specific algorithms ranging from − 0.281 to 1, utility scores will be converted into quality adjusted life years (QALYs) required for cost-utility analysis.

Socio-demographic characteristics

Age, marital status, sexual orientation, children, occupational status, annual gross income, educational attainment level, area of residence/postcode, ethnicity.

Medical characteristics (To be assessed via self-report and confirmed via hospital chart review where available)

Date of MBC diagnosis, date of previous BC diagnosis (if applicable), tumour type (hormone status, site of progression), treatments received or planned (surgery, chemotherapy, radiotherapy, hormonal therapy, other), other health conditions, number of prescription medications (to calculate comorbidity index: Rx-Risk score [42], and other support-services accessed (including psychology).

Social support

The Medical Outcome Study Social Support Survey yields a total-scale score and four subscales: emotional/informational, tangible, affectionate, and positive social interactions [43].

Intervention adherence

Number of visits, session duration, number of modules completed, pages viewed, and worksheets completed [35].

Services Australia-reported health service use and costs

Medicare Benefits Schedule (MBS) data will be accessed to determine the number and costs of primary care visits, medical consultations, treatments, investigations, and out-of-hospital visits; Pharmaceutical Benefits Scheme (PBS) data to estimate quantity and costs of pharmaceuticals.

Public-hospital costing data (For South Australian recruitment site only)

Centralised costing data in public hospitals (Australian Refined Diagnosis Related Groups (AR-DRGs) will be accessed for determining the number and costs of public hospital inpatient episodes. While this only covers public health sector costs and is not available for participants who self-refer this limitation will apply equally to both groups, due to randomisation.