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Postmastectomy
Source: Breast Cancer Treatment (PDQ®)–Health Professional Version, National Cancer Institute.
Source updated: April 25, 2025 · Captured 2026-09-09.
Selected source text with whitespace normalised. This Triangle page is not an NCI PDQ summary.
Context: Radiation Therapy for Breast Cancer / Post–Breast-Conserving Surgery
Postoperative chest wall and regional lymph node adjuvant radiation therapy has traditionally been given to selected patients considered at high risk of locoregional failure after mastectomy. Patients at highest risk of local recurrence meet one or more of the following criteria:[21-23]
Four or more positive axillary nodes.
Grossly evident extracapsular nodal extension.
Lymphovascular space invasion.
Large primary tumors.
Very close or positive deep margins of resection of the primary tumor.
In this high-risk group, radiation therapy can decrease locoregional recurrence, even among patients who receive adjuvant chemotherapy.[24]
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Patients with one to three involved nodes without any of the high-risk factors may be at a lower risk of local recurrence, and the value of routine use of adjuvant radiation therapy in this setting is an area of controversy.
Evidence (postoperative radiation therapy in patients with one to three involved lymph nodes):
The 2005 EBCTCG meta-analysis of 42,000 women in 78 randomized treatment comparisons indicated that radiation therapy is beneficial, regardless of the number of lymph nodes involved.[1][Level of evidence A1]
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The 2005 EBCTCG meta-analysis of 42,000 women in 78 randomized treatment comparisons indicated that radiation therapy is beneficial, regardless of the number of lymph nodes involved.[1][Level of evidence A1]
For women with node-positive disease postmastectomy and axillary clearance (removal of axillary lymph nodes and surrounding fat), radiation therapy reduced the 5-year local recurrence risk from 23% to 6% (absolute gain, 17%; 95% CI, 15.2%–18.8%). This translated into a significant reduction (P = .002) in breast cancer mortality, 54.7% versus 60.1%, with an absolute gain of 5.4% (95% CI, 2.9%–7.9%).
The 2005 EBCTCG meta-analysis of 42,000 women in 78 randomized treatment comparisons indicated that radiation therapy is beneficial, regardless of the number of lymph nodes involved.[1][Level of evidence A1]
In subgroup analyses, the 5-year local recurrence rate was reduced by 12% (95% CI, 8%–16%) for women with one to three involved lymph nodes and by 14% (95% CI, 10%–18%) for women with four or more involved lymph nodes. In an updated meta-analysis of 1,314 women with axillary dissection and one to three positive nodes, radiation therapy reduced locoregional recurrence (2-sided P < .00001), overall recurrence (RR, 0.68; 95% CI, 0.57–0.82; 2-sided P = .00006), and breast cancer mortality (RR, 0.80; 95% CI, 0.67–0.95; 2-sided P = .01).[25][Level of evidence A1]
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The 2005 EBCTCG meta-analysis of 42,000 women in 78 randomized treatment comparisons indicated that radiation therapy is beneficial, regardless of the number of lymph nodes involved.[1][Level of evidence A1]
In contrast, for women at low risk of local recurrence with node-negative disease, the absolute reduction in 5-year local recurrence was only 4% (P = .002; 95% CI, 1.8%–6.2%), and there was not a statistically significant reduction in 15-year breast cancer mortality (absolute gain, 1.0%; P > .1; 95% CI, -0.8%–2.8%).
Further, an analysis of National Surgical Adjuvant Breast and Bowel Project (NSABP) trials showed that even in patients with large (>5 cm) primary tumors and negative axillary lymph nodes, the risk of isolated locoregional recurrence was low enough (7.1%) that routine locoregional radiation therapy was not warranted.[26]
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Publication references
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Preserved source evidence · Not medical advice