Statement: Patients with T1N2M0, T2N1M0, T3N1M1 and TxN1M0 tumors are eliglbe for the primary trial.
Primary_evidence: Inclusion Criteria:   Female gender   Age 18 years   An invasive primary breast cancer of any histology arising from breast parenchyma   Patient must be status post mastectomy or partial mastectomy with an assessment of axillary nodes via sentinel lymph node biopsy and/or axillary lymph node dissection   Pathologic confirmation of metastatic disease in at least one regional lymph node. Regional lymph nodes are defined as the ipsilateral axillary lymph nodes, ipsilateral supraclavicular lymph nodes, and ipsilateral internal mammary lymph nodes. Thus, any T stage is allowed as long as the N stage is 1 and M stage is 0.   Patient signed study-specific consent form. Exclusion Criteria:   Patients with distant metastasis.   Patients who are pregnant or breastfeeding.   Patients with psychiatric or addictive disorders that would preclude obtaining informed consent.   Time between initial diagnosis of breast cancer and start of radiation therapy exceeds 13 months.   Estimated life expectancy judged to be less than one year by patient's treating radiation oncologist.   Prior radiation therapy to the ipsilateral or contralateral breast or thorax.   Primary breast cancer is a lymphoma or sarcoma histology.   Patients with a history of non-skin malignancy <5 years prior to the diagnosis of breast cancer.   Patients requiring radiation to the bilateral breasts.