Postmastectomy Radiotherapy

Publication Date: December 1, 2016


PMRT for patients With T1-2 tumors with one to three positive axillary lymph nodes who undergo ALND

The panel unanimously agreed that the available evidence shows that PMRT reduces the risks of LRF, any recurrence, and breast cancer mortality for patients with T1-2 breast cancer with one to three positive axillary nodes. (EB, H, S)
However, some subsets of these patients are likely to have such a low risk of LRF that the absolute benefit of PMRT is outweighed by its potential toxicities. ( EB , , I , S )
In addition, the acceptable ratio of benefit to toxicity varies among patients and physicians. Thus, the decision to recommend PMRT or not requires a great deal of clinical judgment. The panel agreed clinicians making such recommendations for individual patients should consider factors that may decrease the risk of LRF, attenuate the benefit of reduced breast cancer–specific mortality, and/or increase the risk of complications resulting from PMRT. These factors include: patient characteristics (eg, age > 40 to 45 years, limited life expectancy because of older age or comorbidities, or coexisting conditions that might increase the risk of complications), pathologic findings associated with a lower tumor burden (eg, T1 tumor size, absence of lymphovascular invasion, presence of only a single positive node and/or small size of nodal metastases, or substantial response to NAST), and biologic characteristics of the cancer associated with better outcomes and survival and/or greater effectiveness of systemic therapy (eg, low tumor grade or strong hormonal sensitivity. (IC, I, M)
There are several risk-adaptive models that physicians may find useful in explaining the benefits of PMRT during shared decision making with patients. However, the panel found insufficient evidence to endorse any specific model or to unambiguously define specific patient subgroups to which PMRT should not be administered. (, , L, W)
The decision to use PMRT should be made in a multidisciplinary fashion through discussion among providers from all treating disciplines early in a patient’s treatment course (soon after surgery or before or soon after the initiation of systemic therapy), either in the context of a formal tumor board or by referral. (IC, Ins, S)
Decision making must fully involve the patient, whose values as to what constitutes sufficient benefit and how to weigh the risk of complications against this in light of the best information the treating physicians can provide regarding PMRT in her situation must be respected and incorporated into the final treatment choice. (IC, Ins, S)

PMRT for patients with T1-2 tumors and a positive SNB who do not undergo completion ALND

For patients with clinical T1-2 tumors with clinically negative nodes, SNB is now generally performed at the time of mastectomy, with omission of ALND if the nodes are negative. ALND has generally been performed if the nodes are positive, but there is increasing controversy about whether this is always necessary, especially if there is limited disease in the affected nodes. The panel recognizes that some clinicians omit axillary dissection with one or two positive sentinel nodes in patients treated with mastectomy. This practice is primarily based on extrapolation of data from randomized trials of patients treated exclusively or predominantly with breast-conserving surgery and whole-breast irradiation or breast plus axillary irradiation. In such cases where clinicians and patients elect to omit axillary dissection, the panel recommends that these patients receive PMRT only if there is already sufficient information to justify its use without needing to know that additional axillary nodes are involved. (IC, L, M)
Clinicians may offer ALND for women with early-stage breast cancer with nodal metastases found on SNB who will undergo mastectomy. (, , L, W)

PMRT for patients with clinical stage I or II cancers who have received NAST

Patients with axillary nodal involvement that persists after NAST (eg, less than a complete pathologic response) should receive PMRT. Observational data suggest a low risk of locoregional recurrence for patients who have clinically negative nodes and receive NAST or who have a complete pathologic response in the lymph nodes with NAST. However, there is currently insufficient evidence to recommend whether PMRT should be administered or can be routinely omitted in these groups. The panel recommends entering eligible patients in clinical trials that examine this question. (IC, L, W)

Should RNI include both the IMNs and supraclavicular-axillary apical nodes when PMRT is used in patients with T1-2 tumors with one to three positive axillary nodes?

The panel recommends treatment generally be administered to both the IMNs and the supraclavicular-axillary apical nodes in addition to the chest wall or reconstructed breast when PMRT is used for patients with positive axillary lymph nodes. There may be subgroups that will experience limited, if any, benefits from treating both these nodal areas compared with treating only one or perhaps treating only the chest wall or reconstructed breast. There is insufficient evidence at this time to define such subgroups in detail. Additional research is needed to identify them. (IC, I, M)

Recommendation Grading




Postmastectomy Radiotherapy

Authoring Organizations

Publication Month/Year

December 1, 2016

Supplemental Implementation Tools

Document Type


External Publication Status


Country of Publication


Document Objectives

A joint American Society of Clinical Oncology, American Society for Radiation Oncology, and Society of Surgical Oncology panel convened to develop a focused update of the American Society of Clinical Oncology guideline concerning use of postmastectomy radiotherapy (PMRT).

Target Patient Population

Post mastectomy patients

Inclusion Criteria

Female, Adolescent, Adult, Older adult

Health Care Settings

Ambulatory, Hospital, Operating and recovery room, Outpatient, Radiology services

Intended Users

Nurse, nurse practitioner, physician, physician assistant


Management, Treatment

Diseases/Conditions (MeSH)

D001943 - Breast Neoplasms, D018787 - Radiation Oncology, D011827 - Radiation, D008408 - Mastectomy


breast cancer, radiation therapy, Adjuvant Radiation Therapy, Breast Cancer

Supplemental Methodology Resources

Data Supplement, Methodology Supplement


Number of Source Documents
Literature Search Start Date
January 1, 2014
Literature Search End Date
July 31, 2015
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Specialties Involved
Internal Medicine General, Obstetrics And Gynecology, Oncology, Surgery General, Radiation Oncology, Oncology
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List of Questions
see full text
Description of Study Criteria
see supplement
Description of Search Strategy
Upon approval of the Protocol, a systematic review of the medical literature is conducted. ASCO staff use the information entered into the Protocol, including the clinical questions, inclusion/exclusion criteria for qualified studies, search terms/phrases, and range of study dates, to perform the systematic review. Literature searches of selected databases, including The Cochrane Library and Medline (via PubMed) are performed. Working with the Expert Panel, ASCO staff complete screening of the abstracts and full text articles to determine eligibility for inclusion in the systematic review of the evidence. Unpublished data from meeting abstracts are not generally used as part of normal ASCO guideline development (“Meeting Data”). However, abstract data from reputable scientific meetings and congresses may be included on a case‐by‐case basis after review by the CPGC leadership. Expert Panels should present a rationale to support integration of abstract data into a guideline. The CPGC leadership will consider the following inclusion criteria for the unpublished scientific meeting data: 1) whether the data were independently peer reviewed in connection with a reputable scientific meeting or congress; 2) the potential clinical impact of the unpublished data; 3) the methodological quality and validity of the associated study; 3) the potential harms of not including the data; and 4) the availability of other published data to inform the guideline recommendations.
Description of Study Selection
Literature search results were reviewed and deemed appropriate for full text review by two ASCO staff reviewers in consultation with the Expert Panel Co-Chairs. Data were extracted by two staff reviewers and subsequently checked for accuracy through an audit of the data by another ASCO staff member. Disagreements were resolved through discussion and consultation with the Co-Chairs if necessary. Evidence tables are provided in the manuscript and/or in Data Supplement.
Description of Evidence Analysis Methods
ASCO guideline recommendations are crafted, in part, using the GuideLines Into DEcision Support (GLIDES) methodology. ASCO adopted a five‐step approach to carry out quality appraisal, strength of evidence ratings and strength of recommendations ratings. The ASCO approach was primarily adapted from those developed by the AHRQ,, USPSTF, and GRADE, however with the validation of the GRADE methodology, the sole use of GRADE is being evaluated by the Clinical Practice Guidelines Committee.
Description of Evidence Grading
High: High confidence that the available evidence reflects the true magnitude and direction of the net effect (i.e., balance of benefits v harms) and that further research is very unlikely to change either the magnitude or direction of this net effect. Intermediate: Moderate confidence that the available evidence reflects the true magnitude and direction of the net effect. Further research is unlikely to alter the direction of the net effect; however, it might alter the magnitude of the net effect. Low: Low confidence that the available evidence reflects the true magnitude and direction of the net effect. Further research may change either the magnitude and/or direction this net effect. Insufficient: Evidence is insufficient to discern the true magnitude and direction of the net effect. Further research may better inform the topic. The use of the consensus opinion of experts is reasonable to inform outcomes related to the topic.
Description of Recommendation Grading
ASCO uses a formal consensus methodology based on the modified Delphi technique in clinically important areas where there is limited evidence or a lack of high‐quality evidence to inform clinical guidance recommendations. Evidence Based: There was sufficient evidence from published studies to inform a recommendation to guide clinical practice. Formal Consensus: The available evidence was deemed insufficient to inform a recommendation to guide clinical practice. Therefore, the Expert Panel used a formal consensus process to reach this recommendation, which is considered the best current guidance for practice. The Panel may choose to provide a rating for the strength of the recommendation (i.e., "strong," "moderate," or "weak"). The results of the formal consensus process are summarized in the guideline and reported in the Data Supplement (see the Supporting Documents" field). Informal Consensus: The available evidence was deemed insufficient to inform a recommendation to guide clinical practice. The recommendation is considered the best current guidance for practice, based on informal consensus of the Expert Panel. The Panel agreed that a formal consensus process was not necessary for reasons described in the literature review and discussion. The Panel may choose to provide a rating for the strength of the recommendation (i.e., "strong," "moderate," or "weak"). No recommendation: There is insufficient evidence, confidence, or agreement to provide a recommendation to guide clinical practice at this time. The Panel deemed the available evidence as insufficient and concluded it was unlikely that a formal consensus process would achieve the level of agreement needed for a recommendation.
Description of Funding Source
ASCO provides funding for Guideline Development.
Company/Author Disclosures
ASCO Conflict of Interest Policy complies with the CMSS Code for Interactions with Companies. ASCO requires disclosure by individuals involved in drafting, reviewing, and approving guideline recommendations.
Percentage of Authors Reporting COI