title: The Effect of Adjuvant Trastuzumab on Locoregional Recurrence of Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer Treated with Mastectomy.
abstract: BACKGROUND
  Human epidermal growth factor receptor 2 (HER2) overexpression was associated with locoregional recurrence (LRR) in the preadjuvant trastuzumab era. This study aimed to examine the effect of trastuzumab on LRR in mastectomy patients and whether it varied with postmastectomy radiation (PMRT).
  
  
  METHODS
  From the authors' institutional database, 501 women with stages I-III HER2-positive breast cancer who underwent mastectomy from 1998 to 2007 were identified. A landmark analysis was performed to compare two cohorts: 170 women who received trastuzumab and 281 who did not. Kaplan-Meier methods were used to estimate locoregional recurrence-free survival (LRRFS). A propensity score analysis was used to balance the treatment groups with respect to multiple covariates. Analogous methods were used to study the effect of PMRT.
  
  
  RESULTS
  The women in the trastuzumab group were more likely to be node positive and to receive systemic therapy or PMRT (p < 0.01). The 5-year LRRFS was 98 % in the trastuzumab troup versus 94 % in the no trastuzumab group [hazard ratio (HR) 0.31; 95 % confidence interval (CI) 0.09-1.09; p = 0.07]. After adjustment for multiple covariates, including receipt of chemotherapy and PMRT, trastuzumab decreased LRR rates (HR 0.21; 95 % CI 0.04-0.94; p = 0.04). Among the women who received PMRT, trastuzumab reduced the 5-year LRR rate (0 vs 5 %; p = 0.06). Among those who did not receive PMRT, trastuzumab did not significantly decrease LRR (3 vs 6 %; p = 0.26).
  
  
  CONCLUSIONS
  High rates of locoregional control (5-year rate, 98 %) were observed among patients who received trastuzumab and mastectomy ± PMRT. Trastuzumab decreased LRR in HER2-positive women who received mastectomy and PMRT, suggesting that the largest benefit is seen in a higher-risk subset of patients.
authors.affiliation: Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Lanning
authors.forename: Monica
authors.initials: M
authors.lastname: Morrow
authors.forename: Nadeem
authors.initials: N
authors.lastname: Riaz
authors.forename: Heather L
authors.initials: HL
authors.lastname: McArthur
authors.forename: Chau
authors.initials: C
authors.lastname: Dang
authors.forename: Tracy-Ann
authors.initials: TA
authors.lastname: Moo
authors.forename: Mahmoud
authors.initials: M
authors.lastname: El-Tamer
authors.forename: Kate
authors.initials: K
authors.lastname: Krause
authors.forename: Chun
authors.initials: C
authors.lastname: Siu
authors.forename: Meier
authors.initials: M
authors.lastname: Hsu
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Pei
authors.forename: Beryl
authors.initials: B
authors.lastname: McCormick
authors.forename: Simon N
authors.initials: SN
authors.lastname: Powell
authors.forename: Alice
authors.initials: A
authors.lastname: Ho
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008408:Mastectomy; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D018714:Radiotherapy, Adjuvant; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D000068878:Trastuzumab / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C508053:ERBB2 protein, human