Radiation Therapy and Thymus Function in Young Women With Breast Cancer

Inclusion Criteria:

* Women aged 18 to 50 undergoing mastectomy or breast-conserving surgery for breast cancer of any subtype at DUMC and associated satellite centers
* Histologic documentation of breast cancer based on pathology
* Systemic therapies including hormone therapy, targeted therapy, chemotherapy and immunotherapy as given for breast cancer treatment at the discretion of the treating medical oncologist are allowed and use of such therapies will be documented and included as a covariate
* Willing and able to provide written informed consent

Exclusion Criteria:

* Prior history of therapeutic high-dose irradiation of the thorax (e.g. for treatment of lung cancer, head/neck cancer, Hodgkin disease, etc., not just radiological imaging alone)
* History of thymectomy or treatment with immunosuppressive drugs within the past six months
* Individuals with rheumatoid arthritis or other autoimmune conditions
* Individuals with Down's syndrome
* Male patients