title: Does the number of lymph nodes examined in patients with lymph node-negative breast carcinoma have prognostic significance?
abstract: BACKGROUND
  There are conflicting data on the prognostic significance of the number of lymph nodes examined in patients with lymph node-negative breast carcinoma. Therefore, the authors analyzed the impact of the number of tumor-free axillary lymph nodes on disease-free survival (DFS) in two distinct patient populations.
  
  
  METHODS
  Eight hundred thirty-three consecutive patients with breast carcinoma who underwent mastectomy between 1927 and 1987 and 1094 consecutive patients with breast carcinoma who underwent with breast-conservation therapy between 1984 and 2001 were diagnosed pathologically with negative axillary lymph node status. Patients were stratified into 4 groups according to the number of lymph nodes examined: Group 1 had 1-3 lymph nodes examined, Group 2 had 4-9 lymph nodes examined, Group 3 had 10-20 lymph nodes examined, and Group 4 had >20 lymph nodes examined.
  
  
  RESULTS
  In the mastectomy cohort, with a median follow-up of 153 months, the 10-year DFS rate was 70%, 65%, 79%, and 81% for Groups 1-4, respectively. On multivariate analysis, pathologic tumor size (P<0.001) and the number of lymph nodes examined (P=0.010) were significant predictors for long-term DFS. In the breast-conservation cohort, with a median follow-up of 53 months, the 5-year DFS rate was 90%, 91%, 92%, and 95% for Groups 1-4, respectively. On multivariate analysis, the only predictors of DFS were method of detection (clinically vs. mammographically) (P=0.003) and tumor size (P=0.035).
  
  
  CONCLUSIONS
  The recovery of <10 lymph nodes in lymph node-negative patients who underwent mastectomy resulted in a 10-15% decreased long-term DFS rate compared with patients who had a more extensive axillary assessment. However, the number of lymph nodes examined did not have an impact on the DFS rate in a contemporary cohort of patients who underwent breast-conservation therapy, which included radiation.
authors.affiliation: Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois 60637, USA. jsalama@radonc.uchicago.edu
authors.forename: Joseph K
authors.initials: JK
authors.lastname: Salama
authors.forename: Ruth
authors.initials: R
authors.lastname: Heimann
authors.forename: Fen
authors.initials: F
authors.lastname: Lin
authors.forename: Neil
authors.initials: N
authors.lastname: Mehta
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Chmura
authors.forename: Rachana
authors.initials: R
authors.lastname: Singh
authors.forename: Johnny
authors.initials: J
authors.lastname: Kao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla / Q000601:surgery; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D018572:Disease-Free Survival; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery*; D008207:Lymphatic Metastasis; D015409:Mastectomy, Radical; D015412:Mastectomy, Segmental; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis