Assessment of Biosignature Classification of DCIS for RadioTherapy Benefit Post Lumpectomy (ABCD RT)

Inclusion Criteria: * The patient or a legally authorized representative must provide study-specific informed consent prior to Step 1/Registration and, for patients treated in the U.S., authorization permitting release of personal health information. Breast and Disease Assessment * The patient must be female and greater than or equal to 30 and less than or equal to 85 years of age. (Note: The DCISionRT test is validated only in women between the ages of 30 and 85.) * The patient must have a diagnosis of DCIS less than or equal to 6 cm. (Note: The DCISionRT test is validated only in women with DCIS less than or equal to 6 cm.) * The patient must have an ECOG performance status of less than or equal to 2 (or Karnofsky greater than or equal to 50%). * The patient must have had a bilateral mammogram within 6 months prior to registration. * The patient must have undergone breast conserving surgery with negative surgical margins (greater than or equal to 2 mm). Margin status is assessed on lumpectomy specimen and/or additional margins as determined by the local pathologist. If pathologic examination demonstrates DCIS less than 2 mm from resection edge, additional excisions may be performed to obtain clear margins. Patients with lobular carcinoma in situ (LCIS), atypical lobular hyperplasia (ALH), and/or atypical ductal hyperplasia (ADH) are eligible regardless of margins for these histologies. * The patient must have no suspicious unresected microcalcification, densities, or pal…