Breast cancer is a serious and life-threatening health problem that is increasing all over the world and in Turkey. Although the survival rate increases with the improvement of the diagnosis and treatment processes for breast cancer, cancer patients experience some psychosocial problems both due to their treatment and the disease. Decreases in quality of life, psychological distress, especially depression and anxiety, post-traumatic stress disorder as well as sleep disorders, fatigue, fear of cancer recurrence could be common negative outcomes that experienced by the breast cancer patients. Although, cancer could be such a life-threatening disease, some patients report that they experience positive changes in their lives after the diagnosis of cancer. The concept of Post-Traumatic Growth (PTG) was first developed by Tedeschi and Calhoun (1995). PTG is a concept that refers positive psychological changes after struggling an stressful life event. According to the Functional-Descriptive model of Tedeschi and Calhoun, post-traumatic growth occurs in five areas; relating to others, personal strength, spiritual changes and appreciation of life. In this context, a group intervention program has been developed for PTG, which will bring the person to a better functionality than before the trauma to enhance the Post-Traumatic Growth level of women with breast cancer. The current research project will consist of three arms; therapy group, support group and wait-list. Online group therapy consists of eight sessions that continue approximately 90 minutes. In addition to an active treatment group for PTG, an online support group has been developed by the researchers to investigate the effectiveness of the therapy. Online support group also consists of eight sessions during approximately 90 minutes as in intervention program. Wait-list is considered as a control group. A set of reliable and validated measurement tools will be administered and heart rate variability as a physical measurement will be used to examine the effects of the therapy. The research hypotheses are based on that patients who participated active treatment group will have better PTG level and other related concept with PTG (like higher score of deliberate rumination) and better Heart-Rate Variability scores than other groups. The researcher will plan to take three time measurement: pre-intervention, post-intervention, and 1-month follw-up.

Preliminary studies to development of the programs Before the development of protocol of the current treatment programs, the investigators reviewed related literature and published a systematic review about the related factors for PTG in women with breast cancer. After obtaining the ethical approval the study coordinator interviewed with eight women via telephone to explore the experiences of women with breast cancer. The investigators determined the needs and possible challenges of the illness. Besides, previous similar treatment programs were examined in detail. Later, the investigator developed the study protocol with the supervisor and send the content of the treatment programs to five specialists who have MD in clinical psychology and got feedback and the investigators revisited final version of the treatment programs.

In brief, the research hypotheses are 1) both online group therapy for PTG and online support groups will show better PTG levels and rumination scores, and other secondary measurements (such as psychological distress, heart rate variability, disclosure of distress) than wait-list control. 2) Participants who in online group therapy for PTG will improve better PTG and rumination scores, and secondary measurements' scores compared with the participants in online support groups. 3) The benefits of the treatment programs will be endured for 1-month follow-up measure.

Procedure Ethical approval: This study was approved by the institutional review board of Eskisehir Osmangazi University. All study participants gave written informed consent. Announcements will be posted in various departments of the hospital to participate in the research. First of all, volunteer participants will be assessed through the phone and informed about the research process. If they agree to participate, the investigators will organize a detailed interview. In this interview one of the researchers of the study who is a psychiatrist will apply SCID to eliminate the other possible mental disorder. Patients who meet the criteria will be informed about the group and informed consent forms will be obtained. Before beginning of the treatment program, baseline measurement and ECG Holter measurement will be scheduled by the telephone. After completing baseline measurement, the participants will then be randomly allocated to one of the three groups.

The online treatment programs will be delivered to groups of 6-8 participants by a psychologist and psychiatrist (therapist and co-therapist), eight weekly online sessions. Online sessions will be delivered through an online video-conferencing software (ZOOM). Sample size is determined by g-power analysis. For three-arm randomized controlled trial we plan to recruit at least 51 participants (each group should have at least 17 participants). Before the beginning of the study, the participants will be informed about online video-conferencing platform. The investigators will send a video about the use of platform and also step by step user manual. Each participant in treatment programs should join at least six sessions. If the participants could not complete six sessions, the investigators will admit them drop-out (This information will be declared during the interviews and written informed consent). The investigators will use SPSS 23.0 Package Program for Social Sciences. The descriptive analysis will be performed for frequencies of socio-demographics and clinical information such as cancer stage, treatments. To test the hypothesis, the investigators will conduct a repeated measure ANOVA. The investigators will employ intention to treat and as treated analysis.

Inclusion Criteria:

• women who have been diagnosed with breast cancer for the first and only
• women who have been diagnosed breast cancer in 2018 and later (past four years)
• stage I, II and III patients
• ability to use internet
• having a personal computer or tablet with a camera and microphone
• describing cancer as a stressful life event (using PCL-5 to assess post-traumatic stress level)

Exclusion Criteria:

• recurrence of breast cancer,
• second cancer,
• severe psychological or physical comorbidity

We will recruit women who diagnosed breast cancer. Our sample is considered based on biological sex.