American Radium Society Appropriate Use Criteria Report on Radiation in the Management of Ductal Carcinoma in Situ (DCIS) of the Breast.

Ductal carcinoma in situ (DCIS) of the breast is a distinct biologic entity from invasive cancer with an excellent prognosis which represents about 20% of all mammographically detected breast neoplasms. The primary goal of treatment is to minimize the risk of invasive in-breast recurrence. The American Radium Society (ARS) Appropriate Use Criteria (AUC) expert panel examined the evidence for key questions in contemporary treatment of DCIS related to the benefit of radiation after lumpectomy, the established dose and fractionation radiation regimens and the use of predictive and prognostic assays in treatment management of DCIS. For patients undergoing breast conserving surgery, postoperative radiation to the breast reduces the risk of local recurrence by at least 50%. The absolute benefit depends upon the baseline risk of in breast recurrence based on clinicopathologic features identified in randomized or prospective clinical trials and meta-analyses. These features include age and menopausal status, grade, margin width, tumor size, receptor expression, and presence of comedonecrosis. Randomized and prospective studies have not identified a definitive cohort of patients who do not benefit from adjuvant radiation to reduce in breast recurrence. Margin width appears to be the most significant factor in local recurrence risk. Patients with close or positive margins demonstrate a higher local recurrence risk and benefit from dose escalation by use of a tumor bed boost. Recently developed biosignatures of DCIS in-breast recurrence risk have been validated and found to confer potential clinical utility in the decision-making process regarding recommendations to undergo treatment with adjuvant breast radiation.