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Updated: Jun 2, 2026
Generating a Murine Orthotopic Metastatic Breast Cancer Model and Performing Murine Radical Mastectomy
Published on: November 29, 2018
Irradiation effect after mastectomy on breast cancer recurrence in patients presenting with locally advanced disease
Angie R Taras1, Jason D Thorpe, Astrid D Morris
1Department of Surgery, Swedish Cancer Institute, Swedish Medical Center, Seattle, WA 98104, USA.
Background:
Current guidelines recommend postmastectomy irradiation (PMI) for patients with tumors >5 cm and/or ≥4 positive lymph nodes. This study evaluates the effect of PMI on recurrence and survival within tumor size and node status groups.
Methods:
Locoregional and distant recurrences and survival for different tumor and treatment characteristics were analyzed in 2,797 patients with invasive breast cancer treated with mastectomy.
Results:
Tumor size, positive nodes, extranodal extension, lymphatic/vascular invasion, estrogen receptor/progesterone negative, HER-2 positive, and high grade were associated with significantly increased recurrence. In patients with ≥4 positive nodes and patients with tumors >5 cm and positive nodes, PMI decreased local and distant recurrence (overall 53% vs 24%, P < .001) and increased disease-free survival (P < .001) but not overall survival. In patients with less disease, a benefit from PMI irradiation could not be identified.
Conclusions:
PMI is indicated for patients with ≥4 positive nodes or patients with tumors >5 cm and positive nodes.