Effects of a Mindful Self-Compassion Intervention on Psychological Adjustment in Breast Cancer Survivors

Participants will receive an eight-week Mindful Self-Compassion (MSC) group program through live online videoconferencing, in addition to their usual medical and psychological care. The program consists of one 105-minute session per week, with mindfulness and self-compassion practices, writing, group discussions, and home-practice guidance.

An adapted eight-week Mindful Self-Compassion (MSC) group program for breast cancer survivors, delivered online through live videoconferencing in weekly 105-minute sessions. A licensed clinical psychologist with MSC-related training and group facilitation experience will lead the program, supported by a research staff member with clinical psychology training. The program retains core MSC content involving mindfulness, self-kindness, and common humanity. Activities include guided mindfulness and self-compassion practices, compassionate writing, group sharing, and exercises for responding to difficult emotions and relationships. Participants will receive home-practice guidance and be invited to record practice frequency, duration, and type. To reduce participation demands, sessions are shortened from the standard 150 minutes to 105 minutes, and the midprogram four-hour retreat is omitted.

• MSC

Participants in both groups will continue their existing medical and psychological care as clinically indicated. The study will not restrict necessary treatment or assign a standardized usual-care regimen. Additional psychological care, participation in mindfulness- or compassion-related programs, and major medical treatment changes will be documented.

Participants will continue their usual medical and psychological care without receiving the study's Mindful Self-Compassion (MSC) program during the controlled assessment period. After completing the three-month follow-up assessment (T2), participants will be offered the opportunity to attend the same eight-week MSC program. Their subsequent MSC participation will not be included in the primary controlled comparison.

Participants in both groups will continue their existing medical and psychological care as clinically indicated. The study will not restrict necessary treatment or assign a standardized usual-care regimen. Additional psychological care, participation in mindfulness- or compassion-related programs, and major medical treatment changes will be documented.

Psychological distress will be assessed using the 14-item Hospital Anxiety and Depression Scale (HADS). Each item is scored from 0 to 3. Anxiety and depression items will be combined into a total psychological distress score ranging from 0 to 42, with higher scores indicating greater psychological distress.

Posttraumatic growth will be assessed using a 10-item short form of the Posttraumatic Growth Inventory, with items referring to the breast cancer experience. The measure covers relating to others, new possibilities, personal strength, spiritual change, and appreciation of life. Each item is scored from 0 to 5. Total scores range from 0 to 50, with higher scores indicating greater posttraumatic growth.

Positive self-compassion will be assessed using the six positive-dimension items of the Self-Compassion Scale-Short Form (SCS-SF), covering self-kindness, common humanity, and mindfulness. Items are rated from 1 (almost never) to 5 (almost always). The six item scores will be averaged, yielding a score from 1 to 5. Higher scores indicate greater positive self-compassion. This dimension will be scored and analyzed separately from negative self-compassion.

Negative self-compassion will be assessed using the six negative-dimension items of the Self-Compassion Scale-Short Form (SCS-SF), covering self-judgment, isolation, and over-identification. Items are rated from 1 (almost never) to 5 (almost always). Raw item scores will be averaged without reverse scoring, yielding a score from 1 to 5. Higher scores indicate greater negative self-responding. This dimension will be scored and analyzed separately from positive self-compassion; no combined overall score will be calculated.

Intrusive rumination will be assessed using the 10-item intrusive rumination subscale of the Event Related Rumination Inventory (ERRI), referring to the breast cancer experience. Items assess involuntary, recurring thoughts about the experience and are rated from 0 (not at all) to 3 (often). The 10 item scores will be summed, yielding a subscale total from 0 to 30. Higher scores indicate more frequent intrusive rumination. This subscale will be analyzed separately from deliberate rumination.

Deliberate rumination will be assessed using the 10-item deliberate rumination subscale of the Event Related Rumination Inventory (ERRI), referring to the breast cancer experience. Items assess intentional reflection on the experience and its meaning and are rated from 0 (not at all) to 3 (often). The 10 item scores will be summed, yielding a subscale total from 0 to 30. Higher scores indicate more frequent deliberate rumination. This subscale will be analyzed separately from intrusive rumination.

Cognitive reappraisal will be assessed using the six-item cognitive reappraisal subscale of the Emotion Regulation Questionnaire (ERQ). Items assess the use of changes in thinking to regulate emotional responses and are rated from 1 (strongly disagree) to 7 (strongly agree). The six item scores will be averaged, yielding a subscale score from 1 to 7. Higher scores indicate more frequent use of cognitive reappraisal. This subscale will be analyzed separately from expressive suppression.

Expressive suppression will be assessed using the four-item expressive suppression subscale of the Emotion Regulation Questionnaire (ERQ). Items assess the tendency to inhibit the outward expression of emotions and are rated from 1 (strongly disagree) to 7 (strongly agree). The four item scores will be averaged, yielding a subscale score from 1 to 7. Higher scores indicate more frequent use of expressive suppression. This subscale will be analyzed separately from cognitive reappraisal.

Experiential avoidance will be assessed using the six-item Chinese version of the Acceptance and Action Questionnaire-II (AAQ-II). Instructions and item contexts refer to cancer- and treatment-related experiences. Items are rated from 1 (never true) to 7 (always true). All items are directly scored and summed, yielding a total from 6 to 42. Higher scores indicate greater experiential avoidance and lower psychological flexibility.