Breathing Exercise for Chronic Pain Management in Breast Cancer Survivors

Inclusion Criteria: 1. female breast cancer survivors ≥18 years age; 2. has a confirmed diagnosis of breast cancer at stage I, II or IIIa; 3. has been experiencing pain since cancer diagnosis constantly or intermittently for ≥3 months, with the average pain intensity in the last seven days on a numerical scale ≥4/10 ("0" indicates no pain and "10" indicates the worst pain); 4. has completed active anticancer treatment (such as chemotherapy, radiotherapy, surgery) for at least three months; 5. agrees to participate in the research and is willing to give informed consent; 6. can read and understand Mandarin Chinese. Exclusion Criteria: 1. extremely weak and unable to perform the breathing exercises; 2. mentally incapable (i.e., unable to follow the study instructions); 3. has scheduled pain management interventions, such as having a procedure or operation; 4. receiving other pain relief treatments, such as acupuncture, yoga, qigong, exercise program, etc.; 5. has any pre-existing chronic pain conditions before cancer diagnosis, such as arthritis, rheumatoid arthritis, chronic low back pain, migraines, trigeminal neuralgia, fibromyalgia, joint dysfunction, Complex Regional Pain Syndrome, endometriosis, etc.