Breast cancer patients who had undergone surgery, chemotherapy and radiotherapy suffered from complications, including shoulder stiffness, lymphedema and scar contracture. These symptoms impaired one's ADL function. Rehabilitation may relieved symptoms. However, it is difficult to estimate how long one should receive rehabilitation. The study is trying to establish a machine-learning based model in order to predict the period of rehabilitation.

Breast cancer survivors suffered from complications after surgery, chemotherapy and radiotherapy. These complications include shoulder stiffness, upper limb lymphedema and scar contracture, which altogether impaired one's ADL function. Rehabilitation had been approved to relieved these symptoms effectively. However, many factor may interfere the patient's participation of rehabilitation, making it difficult to estimate how long one should receive rehabilitation. In Taiwan, National Health Insurance provides affordable, accessible and unlimited health care and medical service for all citizens, eliminating many social-economic barriers. Thus we are trying to establish a machine-learning based model in order to predict the period of rehabilitation.

Our study is a retrospective case-control study. The objectives are breast cancer survivors who attended post-surgery rehabilitation at least once for complications. The following data are collected from e-HIS system:

1. Patient characteristic: age, unilateral or bilateral cancer.
2. Surgery type: total, partial or simple mastectomy.
3. Lymphatic surgery: ALND and SLNB
4. Other surgical procedure: breast reconstruction, flap surgery.
5. Combined therapy: chemotherapy, radiotherapy or hormone therapy.
6. Complications: shoulder stiffness, lymphedema, scar contracture (ex., Axillary web syndrome), neurological deficit.
7. The first between operation and first time of rehabilitation.

The primary outcome is the total rehabilitation time, which will be divided as short term (less than 360 min) and long time (more than 360 min).

The data will be processed using WEKA and machine learning algorithms, including Logistic regression, supportive vector machine, K-nearest neighbors, decision tree and random forest.

Inclusion Criteria:

• patients who received operation for breast cancer
• attended rehabilitation at least once for breast cancer related complications

Exclusion Criteria:

• patients who received rehabilitation for other reasons rather than surgical complications
• patients who are transfered to other hospital for rehabilitation

Breast cancer patients that are registered at the case management system of Taichung Vetetans General Hospital