Histologically confirmed invasive carcinoma of the breast of any of the following histologies (ductal, lobular, mammary, medullary, or tubular); patients with metaplastic breast cancer are not eligible

Patients will be staged according to the TNM staging system

No prior therapeutic radiation therapy to the chest, neck or axilla; prior radioactive oral iodine is permitted

No prior history of ipsilateral breast cancer (invasive disease or ductal breast carcinoma in situ [DCIS]); lobular carcinoma in situ (LCIS) and benign breast disease is allowed

No history of prior or concurrent contralateral invasive breast cancer; benign breast disease, LCIS or DCIS of contralateral breast is allowed

No history of prior or concurrent contralateral invasive breast cancer; benign breast disease, LCIS or DCIS of contralateral breast is allowed

No active collagen vascular diseases, such as: systemic lupus erythematous, scleroderma, or dermatomyositis

Negative inked histologic margins from mastectomy pathology (no invasive cells at margin). Patients with DCIS at margin are eligible.

No significant post mastectomy complications in the ipsilateral breast requiring an unplanned re-operation or admission for intravenous (IV) antibiotics; re-operation for margins evaluation, nodal completion and routine reconstruction is acceptable

Radiation oncologist intends to treat all target volumes and respect all normal tissues in accordance with the dosimetric constraints described (simulation before registration recommended)

Radiation oncologist is planning to treat regional lymph nodes including internal mammary nodes and meet acceptable protocol dosimetric requirements

Radiation oncologist is NOT planning to utilize a chest wall/scar boost

Patient must have undergone immediate reconstruction at the time of mastectomy or be planning to undergo reconstruction within 18 months after radiation

Treating physician and patient must plan to start radiation treatment within the timeframes specified in protocol.

If a tissue expander is utilized it needs to be a fluid filled expander, NO air expander (unless completely deflated) during radiation therapy

For patients with diabetes, hemoglobin A1C test must have been performed =\< 90 days prior to registration

No co-existing medical conditions with life expectancy \< 5 years

No other malignancy within 5 years of registration with the exception of basal cell or squamous cell carcinoma of the skin treated with local resection only or carcinoma in situ of the cervix

Negative pregnancy test (serum or urine HCG) in women of child-bearing potential = 7 days prior to registration. Patients who have received a bilateral tubal ligation still require a negative pregnancy test for eligibility. A female of childbearing potential is a sexually mature female who has not undergone a hysterectomy or bilateral oophorectomy and has not been naturally postmenopausal for at least 12 consecutive months

Women of child-bearing potential must agree to utilize a form of birth control or agree to undergo sexual abstinence during radiation therapy

Eastern Cooperative Oncology Group (ECOG) (Zubrod) performance status 0-1

Patients must be able to read and comprehend English, in order to be able to complete study questionnaires; however, patients participating through Canadian Cancer Trials Group (CCTG) institutions who can read and comprehend French are eligible

Pregnancy;

Co-existing medical conditions with life expectancy <5 year;

Other malignancies within 5 years of registration

Patients with metaplastic breast cancer are not eligible

• Obstetrics and Gynecology

• Oncology (Adult)

• Alliance for Clinical Trials in Oncology