Synchronous or previous contralateral invasive breast cancer; (patients with synchronous and/or previous contralateral DCIS or LCIS are eligible)
No history of prior or concurrent contralateral invasive breast cancer; benign breast disease; LCIS or DCIS of contralateral breast is allowed
For those patients who also undergo contralateral breast surgery, if invasive disease is found in the contralateral breast, the patient is not eligible for registration /randomization
History of invasive breast cancer or contralateral DCIS
Synchronous or previous contralateral invasive breast cancer or DCIS; (patients with synchronous and/or previous contralateral LCIS are eligible)
Synchronous contralateral breast cancer requiring RT
Patients with known bilateral invasive breast cancer; patients with contralateral in situ breast carcinoma are eligible
Unifocal primary disease NOTE: Patients with multifocal and/or multicentric in breast cancer, or evidence of EIC are NOT eligible. Patients with contralateral disease will remain eligible.
Previous history of contralateral invasive breast cancer. (Patients with synchronous and/or previous contralateral DCIS or LCIS are eligible.)
Invasive cancer in the contralateral breast
History of prior or concurrent contralateral invasive breast cancer; benign breast disease, LCIS or DCIS of contralateral breast is allowed
Invasive cancer in the contralateral breast
Patients with contralateral hilar involvement
Previous randomization for a contralateral procedure as part of this study
Breast implant in the breast to be treated (contralateral breast implant is acceptable)
Invasive cancer in the contralateral breast
Invasive cancer in the contralateral breast
Presence of nodules considered neoplastic in contralateral lobes (Ma)
Any previously treated contralateral breast carcinoma or synchronous ipsilateral breast carcinoma
Biopsy confirmed multifocal, multicentric, or contralateral disease that is invasive or non-invasive
Patients with a prior history of contralateral breast cancer are eligible if they have no evidence of recurrence of their initial primary breast cancer
Synchronous or previous contralateral invasive breast cancer; (patients with synchronous and/or previous contralateral ductal carcinoma in situ [DCIS] or lobular carcinoma in situ [LCIS] are eligible)
History of any prior (ipsi- and/or contralateral) invasive breast cancer
Involved contralateral hilar nodes
Clinical T-Tc, any N, M invasive breast cancer, by American Joint Committee on Cancer (AJCC) th edition clinical staging, with the goal being surgery to complete excision of the tumor in the breast and the lymph node;\r\n* The extent of disease is a solitary lesion where the lesion: \r\n** is palpable\r\n** size can be measured bi-dimensionally by tape, ruler or caliper technique, and\r\n** largest tumor diameter is at least . cm (that is considered measurable by the World Health Organization[WHO] criteria)\r\n* Note:\r\n** Patients with contralateral invasive breast cancer are not eligible\r\n** Patients with contralateral ductal carcinoma in situ (DCIS) are eligible\r\n** Patients with multifocal/multi-centric invasive breast cancer are not eligible; additional foci of DCIS in the same breast are acceptable
Patients with recurrent breast cancer; patients with contralateral second primary breast cancers are eligible
For patients with bilateral or multifocal/multicentric breast cancers, one of the following criteria must be met to enroll: () each cancer individually meets criteria for enrollment (only ONE tumor has to undergo central confirmation for HER), OR () at least one tumor meets eligibility (per tumor size/nodes/subtype outlined above) and the other foci in the ipsilateral or contralateral breast are also HER-positive but are too small for enrollment (e.g., a patient is eligible if a cancer is TN and HER-positive in one breast, but the contralateral breast has a Tb HER+ cancer that isnt eligible on its own, OR, () at least one tumor meets eligibility and the other foci in the ipsilateral or contralateral breast are HER-negative and do not meet criteria for adjuvant chemotherapy per provider discretion (e.g. if a patient has a HER-positive tumor meeting eligibility but also has a second, HER-negative, small, node-negative, ER+, low grade cancer present, she is still eligible for enrollment); however, in the specific case that a second breast cancer is stage III and HER-negative, that patient is excluded (because the second cancer is high-risk and likely will require non-HER-directed therapy)
Patients with stage III, HER-negative cancer in the contralateral breast
Prior radiation therapy or implant in the contralateral breast
Surgeons opinion at the time of surgery that the subjects well-being (e.g. significant comorbidities, intraoperative findings of a higher stage cancer or other independent acute health problems) would be compromised; if the contralateral breast is undergoing a nipple-sparing mastectomy with reconstruction as well, then the contralateral breast can be studied so long as there is no compromise to any element of their care
History of any prior (ipsilateral and/or contralateral) invasive breast carcinoma
Patients with synchronous contralateral invasive breast cancer are excluded
Any previously treated contralateral invasive breast carcinoma or synchronous contralateral breast carcinoma
Contralateral hilar node involvement
Invasive cancer or DCIS in the contralateral breast
Advanced (TN-/T- N any) invasive cancer in the contralateral breast
Synchronous or previous contralateral invasive breast cancer; (patients with contralateral DCIS not treated with radiation are eligible)
Untreated extensive stage (ES)-SCLC, defined as those patients with extrathoracic metastatic disease, malignant pleural effusion, bilateral or contralateral supraclavicular lymphadenopathy, or contralateral hilar adenopathy
Previous (required active treatment within  years) or concomitant malignancy except basal cell cancer, in situ carcinoma of the cervix, or contralateral breast cancer. Subjects with a prior contralateral breast malignancy can be included if they did not receive any chemotherapy.
No history of prior or concurrent contralateral invasive breast cancer; benign breast disease, LCIS or DCIS of contralateral breast is allowed
Patients with a history of prior (ipsilateral [ipsi]- and/or contralateral) invasive BC
Prior radiation therapy to the contralateral (unaffected) breast
Prior history of contralateral (unaffected) breast augmentation with breast implant placement
Patients with previous contralateral invasive breast cancer treated with anti-cancer therapy are eligible
Biopsy confirmed benign calcifications in at least one breast (same or contralateral breast)