Improved Locoregional Control for Patients With T1-2N1 Triple-Negative Breast Cancer Treated With Radiation Therapy Following Modified Radical Mastectomy

Abstract

HER 2 positive) and HER 2-discordant (HER 2-positive primary breast tumors had HER 2 negative) tumors were compared. Results: The median follow-up time was 24 months (0.75-74 months). Receptor status was available in 226 patients: 31.8% Luminal A, 17.7% Luminal B, 29.6% HER 2, 20.8% Basal. Median survival from brain metastases in Luminal A, Luminal B, HER 2, Basal subtype was 11 months (95% CI Z 9.34-12.65), 9.4 months (95% CI Z 6.44-12.09), 10 months (95% CI Z 6.57-13.42) and 5 months (95% CI Z 2.61-7.39), respectively (p Z 0.01). In HER 2-positive patients (Luminal B and HER 2 subgroups), survival after WBRT (40 vs 32 weeks; P Z 0.029), and CNS progression free survival after WBRT (24 vs 20 weeks; P Z 0.037) was significantly longer compared with HER 2negative patients. For the 44 cases receiving repeat brain radiation therapy, HER 2-positive patients also had longer survival and CNS disease free survival after brain irradiation. Thirtyseven of 108 HER 2-positive patients had metastatic tumor biopsy results available for review. Twelve (32%) of the 37 patients had HER 2-discordant metastatic tumors. Patients with discordant HER 2 status had shorter survival after WBRT than did patients with concordant HER 2 status (P Z 0.046). Conclusions: Our findings indicate that HER 2-positive breast cancer patients with brain metastasis had better prognosis after brain radiation therapy. Loss of HER 2-positive status in metastatic tumors can occur in patients with primary HER 2-positive breast cancer. The need for biopsies of metastatic lesions to accurately determine patient prognosis and appropriate use of tailored brain radiation therapy for brain metastases, and target systemic therapy after WBRT based on molecular subtypes should be considered. Author Disclosure: S. Lai: None. C. Huang: None. C. Wang: None. Y. Chen: None. K. Lan: None. A. Cheng: None. S. Kuo: None.