Outcomes According to Breast Cancer Subtype in Patients Treated With Accelerated Partial Breast Irradiation

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• 作者：J. Ben Wilkinson¹ ; ^{j.ben.wilkinson@gmail.com} ; Chirag Shah² ; Mitual Amin³ ; Laura Nadeau⁴ ; Simona F. Shaitelman⁵ ; Peter Y. Chen² ; Inga S. Grills² ; Alvaro A. Martinez⁶ ; Christina K. Mitchell² ; Michelle F. Wallace² ; Frank A. Vicini⁶
• 关键词：APBI ; Brachytherapy ; Breast cancer subtype ; Radiotherapy ; Triple negative
• 刊名：Clinical Breast Cancer
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：17
• 期：1
• 页码：55-60
• 全文大小：173 K
• 卷排序：17

文摘

The purpose of the study was to determine outcomes for patients treated with accelerated partial breast irradiation (APBI) on the basis of breast cancer subtype (BCST).Patients and MethodsOur single-institution, institutional review board-approved APBI database was queried for patients who had complete testing results for the estrogen (ER), progesterone (PR), and HER2/neu receptors to determine outcomes for each BCST. Women were assigned as luminal A (LA), luminal B (LB), HER2, and basal BCST using their ER, PR, and HER2/neu receptor status. Degree of ER expression supplemented the receptor-based luminal BCST assignment. Two hundred seventy-eight patients had results for all 3 receptors (LA = 164 [59%], LB = 81 [29%], HER2 = 5 [2%], basal = 28 [10%]), which were submitted for analysis (ipsilateral breast tumor recurrence [IBTR], regional nodal failure, distant metastasis [DM], disease-free survival [DFS], cause-specific survival [CSS], and overall survival [OS]).ResultsMedian follow-up was 5.4 years (range, 0.1-12.4 years). Basal and HER2 subtype patients had higher histologic grades (Grade 3 = 75% vs. 10% LA/LB; P < .001), larger tumors (13.0 mm basal vs. 10.7 mm LA/LB; P = .059), and were more likely to receive chemotherapy (68% vs. 15% LA/LB; P < .001). Margin and nodal status were similar among BCSTs. At 5 years, IBTR rates were similar (1.8%, 2.9%, 0%, and 4.8%) for LA, LB, HER2, and basal subtypes, respectively (P = .62). DM was only seen in LA (2.9%) and LB (1.3%) (P = .83). DFS (95%-100%), CSS (97%-100%), and OS (80%-100%) were not statistically different (P = .97, .87, .46, respectively).ConclusionFive-year local control rates after breast-conserving surgery, APBI, and appropriate systemic therapy are excellent for luminal, HER2, and basal phenotypes of early-stage breast cancer; however, further study of receptor subtype effect on risk stratification in early-stage breast cancer is needed.