Study of Radiation Fractionation on Patient Outcomes After Breast REConstruction (FABREC) for Invasive Breast Carcinoma

Inclusion Criteria:

1. Diagnosed with clinical or pathologic stage I-III invasive breast cancer with TX-T3 tumor
2. Has been treated with mastectomy
3. Has undergone immediate reconstructive surgery with placement of a tissue expander or permanent implant at time of mastectomy
4. Is a candidate for unilateral post-mastectomy radiation therapy as per National Comprehensive Cancer Network (NCCN) guidelines (post-mastectomy radiation therapy is indicated for most patients with positive lymph nodes at time of surgery and infrequently for selected node-negative patients)
5. Use of bolus is permitted, but not required
6. Age ≥18

Exclusion Criteria:

1. T4 cancer
2. Recurrent breast cancer or history of prior breast radiation therapy
3. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, and/or mental health illness that the consenting investigator feels would affect patient's ability to participate in this study
4. Pregnant or nursing
5. History of a different malignancy except for the following circumstances:

* Disease-free for at least five years and deemed by the investigator to be at low risk for recurrence of that malignancy (\<5 %).
* Cervical cancer in situ and basal cell or squamous cell carcinoma of the skin
6. Breast cancer requiring bilateral breast/chest wall radiation therapy.