title: Incidence of axillary lymph node metastases in T1a and T1b breast carcinoma.
abstract: BACKGROUND
  We investigated the incidence of axillary lymph node metastases in patients with T1a (< or = 0.5 cm) and T1b (> 0.5 cm and < or = 1.0 cm) breast cancers.
  
  
  METHODS
  The charts of 2000 patients who underwent axillary lymph node dissection for breast cancer at our institution from 1989 to 1991 were reviewed. Of these, 81 patients had T1a and 166 had T1b primary breast cancers.
  
  
  RESULTS
  Among the 247 patients with T1a and T1b breast cancers, nodal metastases were present in 30 (12.1%), with a 7.4% positivity rate for patients with T1a and 14.5% positivity rate for T1b tumors. Of the 212 patients who had > or = 10 nodes dissected, 29 (13.7%) had positive nodes. Of those, 6 of 60 (10.0%) patients with T1a and 23 of 152 (15.1%) with T1b tumors had positive nodes. The presence of lymphovascular invasion (LVI) predicted a significantly higher nodal positivity rate (27.8% vs. 10.9%, p = 0.05).
  
  
  CONCLUSIONS
  Of patients with adequately evaluated axillae, 10% with T1a and 15% with T1b cancers were found to have nodal metastases. Although LVI was significantly associated with a higher risk of lymph node metastases, we could not characterize any subgroup at acceptably low risk of nodal positivity. Until a more useful prognostic indicator is discovered, axillary dissection should continue to be part of the mainstay of management for small breast cancers.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: E R
authors.initials: ER
authors.lastname: Port
authors.forename: L K
authors.initials: LK
authors.lastname: Tan
authors.forename: P I
authors.initials: PI
authors.lastname: Borgen
authors.forename: K J
authors.initials: KJ
authors.lastname: Van Zee
mesh_terms: D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging