The following are the key changes for early-stage breast cancer:

• Recommendations for axillary staging have been separated for patients who undergo breast-conserving surgery vs those who undergo mastectomy, creating two individual pathways.
• For node-negative (N0) disease, internal mammary nodal irradiation should be considered when patients have centrally or medially located tumors.
• Radiotherapy recommendations for node-positive patients were also modified to reflect the benefit of whole-breast radiotherapy with inclusion of any portion of the undissected axilla at risk, with or without a boost to the tumor bed.
• Management of positive sentinel nodes after mastectomy and sentinel node biopsy remains controversial.  The NCCN has omitted the inclusion axillary lymph node dissection for patients with clinically N0 T1/T2 tumors and no more than two positive nodes on sentinel lymph node biopsy for whom postmastectomy radiotherapy is planned. (The previous version stated that if a sentinel node–positive patient did not meet ACOSOG Z0011 criteria, axillary lymph node dissection was required.) Also, after mastectomy, in patients who were initially clinically N0 but are pathologically node-positive on sentinel lymph node biopsy and do not undergo axillary lymph node dissection, radiotherapy should include the undissected axilla at risk, with or without coverage of the other regional nodal basins.
• The section on neoadjuvant therapy underwent major reformatting. The assessment of complete vs partial response has been replaced with the assessment of the ability to undergo breast-conserving surgery.
• For patients with clinically or pathologically node-positive disease receiving neoadjuvant therapy and who have not undergone axillary lymph node dissection, radiation should cover the entire axilla, regardless of whether a pathologic complete response was achieved in the nodes.
• For patients with positive nodes after neoadjuvant therapy, the radiation field should cover any portion of the undissected axilla; for those who are clinically node-negative and remain pathologically node-negative following sentinel lymph node biopsy, radiation is not necessary after mastectomy.
• Repeat sentinel lymph node biopsy can be considered for patients with a local breast recurrence after breast-conserving surgery or after mastectomy.
• Specifics regarding the delivery of radiation and its sequencing with systemic therapy agents were updated.