Patients must have metastatic and/or recurrent (distant or locoregionally recurrent) breast cancer and be HER non-over expressing per American Society of Clinical Oncology (ASCO)-College of American Pathologists (CAP) HER testing guidelines ( or + by immunohistochemistry [IHC]; and/or HER ratio < . and HER copy number < signals/cell by in-situ hybridization [ISH])\r\n* Local Regional Recurrence\r\n** In the breast (after preserving therapy)\r\n** In the chest wall (after mastectomy)\r\n** In the ipsilateral/parasternal/infra-or supraclavicular lymph nodes\r\n** In the skin of the chest wall (not breast)\r\n** In the reconstructed breast Patients who received breast/axilla/post-mastectomy chest wall radiotherapy must be after last dose of radiotherapy and must have sufficient resolution of side effects. Advanced breast cancer with locally recurrent chest wall disease not amenable to surgical excision\r\n* Distant sites of disease are allowed\r\n* Prior radiation to the chest wall is not required Patients enrolled in the study will meet standard criteria for whole breast XRT or chest wall XRT for patients who have had mastectomies Must be proceeding with breast/chest wall and nodal radiation therapy including internal mammary node treatment Prior radiotherapy to the ipsilateral chest wall or ipsilateral breast or thorax; individuals with prior radiotherapy in the contralateral breast or chest wall are eligible Histologic confirmation of breast cancer resected by mastectomy with or without immediate reconstruction and chest wall and regional nodal irradiation planned Boosts to the chest wall after mastectomy; nodal boosts are allowed Breast cancer that involves the skin or chest wall Patients must have an accessible lesion in the breast/chest wall/axilla which has not been previously thermally ablated; prior breast irradiation is acceptable if the lesion has recurred or grown following radiation Prior radiotherapy to the ipsilateral chest wall or breast for any malignancy Prior chest wall radiation Requires left chest wall post-mastectomy radiation with or without bolus Conventional chest wall radiation delivery dose of . Gy/ fractions with or without a boost (boost will not be evaluated for endpoints) Unresectable adenocarcinoma of the breast involving chest wall, regional nodes, or distant site Prior radiation to the breast or chest wall Prior radiation to the breast or chest wall Scheduled for intraoperative radiation of breast or chest wall At least one accessible and injectable lesion in the locoregional area (ie. breast, chest wall, skin nodule or mass, axillary or supraclavicular lymph node) of at least centimeter (cm); (ultrasound imaging may be used as clinically indicated) Evidence of T disease (e.g., involvement of the chest wall, skin, dermal lymphatics, or inflammatory breast cancer) Histological confirmation of recurrence of chest wall with or without distant metastasis disease History of radiation to the chest wall or breast being studied Unifocal malignant tumor that does not exceed mm in diameter and measures at least mm away from the skin and chest wall Cluster of microcalcifications that do not exceed mm in diameter and measures at least mm away from the skin and chest wall Tumor invasion of the skin including dermis, chest wall, or pectoralis musculature Pathologically proven diagnosis of breast cancer with clinical evidence of recurrent disease on the chest wall following treatment that included radiotherapy, and for which there is no current standard of care or curative resection able to be performed Patients are permitted to have received prior therapy, but must have received a minimum of Gy to the chest wall with a minimal interval since completion of radiation therapy equal to or greater than months; patients who have previously received more than one course of radiotherapy to the breast and/or chest wall OR have received a cumulative dose to the chest wall in excess of Gy will not be considered eligible Prior radiotherapy to the ipsilateral chest wall for any malignancy. Prior radiation to the chest wall or mediastinum if the radiation field involves the heart Patients must have newly diagnosed metastatic disease; note this may include non-measurable chest wall recurrence No evidence of disease outside the breast or chest wall, except ipsilateral axillary lymph nodes No evidence of disease outside the breast or chest wall, except ipsilateral axillary or internal mammary lymph nodes Histologically documented recurrent/metastatic adenocarcinoma of the breast with a recurrence on the chest wall (or its overlying skin): Subjects with ulcerative chest wall disease defined as non-healing wounds consistent with cancer are eligible. One or more radiation treatment(s) to the chest wall or breast up to a maximum prior dose of , cGy in the hyperthermia field (not administered less than days prior to enrollment). Has a condition which may interfere with the hyperthermia portion of the trial such as: functioning cardiac pacemaker; metal plates, rods or prosthesis of the chest wall, breast reconstruction with implants, severe numbness and/or tingling of the chest wall or breast, skin grafts and/or flaps on the breast or chest wall. Radiation oncologist is NOT planning to utilize a chest wall/scar boost Breast cancer requiring bilateral breast/chest wall radiation therapy Must not have had history of breast cancer, breast surgery, radiation to the chest wall Women with local (i.e., same breast, surgical scar, chest wall) or regional (i.e., lymph nodes) recurrent disease Women with breast cancer who plan to undergo radiation therapy to the breast or chest wall Women who have undergone prior radiotherapy to the chest wall and/or breast Prior radiation therapy to the ipsilateral chest wall or thorax Patients requiring a chest wall boost Patients with prior radiation to the breast/chest wall of the ipsilateral breast Prior history of breast cancer, breast/chest wall/axillary radiation therapy Prior receipt of ipsilateral breast or chest wall radiation >= months from all previous breast cancer treatment (including surgery for invasive cancer, chest wall radiotherapy, chemotherapy, trastuzumab and endocrine therapy) Has lesions involving chest wall Pacemaker of other implantable device in the chest wall No prior history of chest wall radiation HEALTHY VOLUNTEER: A history of chest wall trauma or surgery, or dermatologic disorders, which could be expected to disrupt lymphatic drainage of the chest wall Has lesions involving chest wall Subject has pacemaker or other implantable device in the chest wall. Patient deemed clinically appropriate for adjuvant breast or chest wall radiation following surgery A tumor with direct extension to the chest wall and/or to the skin.