Table 4 EMPOWER study outcomes

Empowerment

Empowerment Scale for Women with Breast Cancer

30 items and 3 factors. Factors include ‘intrapersonal factor’ (14 items), ‘interactional factor’ (8 items), and ‘behavioral factor’ (8 items). 5-point Likert scale. High score indicates higher empowerment.

Goodness of fit of the final research model was very appropriate as shown by χ²/df = 1.86, TLI = 0.90, CFI = 0.92, SRMR = 0.06, and RMSEA = 0.05. Criterion validity was evaluated by total correlation with the Cancer Empowerment Questionnaire 0.78. Cronbach’s alpha for total items was 0.93, and test-retest reliability was 0.69 [29].

Self-efficacy

Korean version of the Cancer Survivors’ Self-Efficacy Scale

10 items and 2 factors. Factors include ‘Self-efficacy for managing health problems’ (5 items) and ‘self-efficacy for seeking help and support’ (5 items). 10-point Likert scale. Higher score indicates higher self-efficacy.

Construct validity was evaluated with general self-efficacy (0.511), anxiety (−0.596), depression (− 0.554) and health-related quality of life (0.586). Cronbach’s alpha of total scale and subscales was 0.86–0.92 [30].

mental adjustment

The Mini-Mental Adjustment to Cancer

29 item and 4 factors. Factors include Helpless-Hopeless (HH), Anxious Preoccupation (AP) Positive Attitude (PA), Cognitive Avoidance (CA), and Fighting Spirit (FS).

Construct validity was evaluated with each of anxiety and depression subscales of HADS, AP (0.63, and 0.58), HH (0.54, and 0.59), FS (−0.30, and − 0.37), and PA (− 0.19, and − 0.23). Cronbach’s alpha was 0.50–0.86 and test–retest reliability was 0.68–0.88 [32].

Anxiety and depression

Hospital Anxiety and Depression Scale

14 item and 2 subscales. Subscales are ‘an anxiety (HADS-A)’ and ‘a depression (HADS-D)’.

4-point Likert scale. Higher score indicates greater anxiety or depression.

Construct validity of HADS-D was evaluated with Beck Depression Inventory 0.80, and HADS-A with Self-Rating Anxiety Scale was 0.79. Items of the HADS-A and corrected item total score was 0.55 and HADS-D was 0.47. Cronbach’s alpha for total items was 0.89 and 0.86 [35].

HRQOL

36-Item Short-Form Survey

36 items, 8 subscales and 2 domains. Domains include ‘physical component’ and ‘mental component’. Each subscale is scored 0 to 100. Higher score indicates better functioning and well-being.

The SF-36 has been validated in South Korea. Cronbach’s alpha was 0.89 for physical component, 0.87 for mental component, and 0.93 for total score [37].