title: Basal subtype, as approximated by triple-negative phenotype, is associated with locoregional recurrence in a case-control study of women with 0-3 positive lymph nodes after mastectomy.
abstract: OBJECTIVE
  Basal subtype, as approximated by the triple-negative phenotype (ER-PR-Her2-), has correlated with higher LRR in recent studies. Indications for postmastectomy RT (PMRT) in women with 0-3 positive lymph nodes remain unclear. We evaluated the importance of biologic subtype in a cohort of women with LRR after mastectomy.
  
  
  METHODS
  We identified 22 women with 0-3 positive lymph nodes at our institution who were initially treated with mastectomy (without post-mastectomy radiation), suffered LRRs, and had paraffin-embedded tissue blocks from the primary mastectomy specimen available for staining. None of these women received PMRT. We case-control matched these to 29 women with 0-3 positive nodes who had mastectomy (no PMRT) and remained without evidence of disease at last follow-up and had available primary specimens for processing. We matched controls for age (±3 years) and follow-up duration (<5 year vs. more). Paraffin-embedded specimens were used to construct a triple-redundant tissue microarray. We used conditional logistic regressions to study the association between each predictor and LRR. Results were summarized based on odds ratio (OR).
  
  
  RESULTS
  On univariate analysis, ER+, PR+, or the combination was strongly associated with lower odds of LRR. Basal subtype, as approximated by ER-PR-Her2- (TN), was associated with higher LRR (OR 8.5, p = 0.048). Use of chemotherapy also was associated with lower LRR (OR 0.126, p = 0.0073).
  
  
  CONCLUSIONS
  Our data are concordant with reports from others demonstrating that TN phenotype is associated with higher LRR and can be considered along with other predictors of LRR when selecting women for PMRT.
authors.affiliation: Department of Radiation Oncology, Robert Wood Johnson University Hospital, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA, atif.j.khan@rutgers.edu.
authors.forename: A J
authors.initials: AJ
authors.lastname: Khan
authors.forename: S A
authors.initials: SA
authors.lastname: Milgrom
authors.forename: N
authors.initials: N
authors.lastname: Barnard
authors.forename: S A
authors.initials: SA
authors.lastname: Higgins
authors.forename: M
authors.initials: M
authors.lastname: Moran
authors.forename: Haseeba
authors.initials: H
authors.lastname: Shahzad
authors.forename: S
authors.initials: S
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Goyal
authors.forename: F
authors.initials: F
authors.lastname: Al-Faraj
authors.forename: L
authors.initials: L
authors.lastname: Kirstein
authors.forename: T
authors.initials: T
authors.lastname: Kearney
authors.forename: B G
authors.initials: BG
authors.lastname: Haffty
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000032:analysis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008408:Mastectomy; D009364:Neoplasm Recurrence, Local / Q000737:chemistry* / Q000473:pathology*; D010641:Phenotype; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012189:Retrospective Studies; D064726:Triple Negative Breast Neoplasms / Q000737:chemistry* / Q000473:pathology* / Q000628:therapy
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone