title: Outcomes of breast cancer patients with triple negative receptor status treated with accelerated partial breast irradiation.
abstract: OBJECTIVE
  Triple negative receptor status (TNRS) of patients undergoing breast-conserving therapy treated with whole-breast irradiation has been associated with increased distant metastasis and decreased disease-free and overall survival. This paper reports the outcomes of TNRS patients treated with accelerated partial breast irradiation (APBI).
  
  
  METHODS
  We studied 455 patients who received APBI at our institution, using interstitial, intracavitary, and three-dimensional conformal radiation therapy. TNRS was assigned if a patient tested negative for all three (ER [estrogen receptor], PR [progesterone receptor], and HER2/neu) receptors. Of 202 patients with all receptor results available, 20 patients were designated TNRS, and 182 patients had at least one receptor positive (RP). We analyzed ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), distant metastasis (DM), and overall survival (OS).
  
  
  RESULTS
  Mean follow-up was 4.1 years for the TNRS group and 5.1 years for the RP cohort (p = 0.11). TNRS patients had a higher histologic grade (59% TNRS vs. 13% RP; p < 0.001). Mean tumor size, stage N1 disease, and margin status were similar. Based on a 5-year actuarial analysis, the TNRS cohort experienced no IBTR, RNF, or DM, with an OS of 100% versus rates of 1.4% IBTR, 1.5% RNF, and 2.8% DM in the RP cohort (p > 0.52). OS for the RP cohort was 93% at 5 years (p > 0.28).
  
  
  CONCLUSIONS
  In our patient population, TNRS conferred a clinical outcome similar to that of patients with RP disease treated with APBI. Further investigation with larger patient populations and longer follow-up periods is warranted to confirm that APBI is a safe and effective treatment for patients with localized TNRS breast cancer.
authors.affiliation: Department of Radiation Oncology, William Beaumont Hospital, Beaumont Cancer Institute, Royal Oak, Michigan 48073, USA.
authors.forename: J Ben
authors.initials: JB
authors.lastname: Wilkinson
authors.forename: Robert E
authors.initials: RE
authors.lastname: Reid
authors.forename: Simona F
authors.initials: SF
authors.lastname: Shaitelman
authors.forename: Peter Y
authors.initials: PY
authors.lastname: Chen
authors.forename: Christine K
authors.initials: CK
authors.lastname: Mitchell
authors.forename: Michelle F
authors.initials: MF
authors.lastname: Wallace
authors.forename: Kimberly S
authors.initials: KS
authors.lastname: Marvin
authors.forename: Inga S
authors.initials: IS
authors.lastname: Grills
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Margolis
authors.forename: Frank A
authors.initials: FA
authors.lastname: Vicini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001918:Brachytherapy / Q000379:methods; D001943:Breast Neoplasms / Q000737:chemistry* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis*; D009364:Neoplasm Recurrence, Local; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis*; D011980:Receptors, Progesterone / Q000032:analysis*; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone