title: When is a lymph node dissection a lymph node dissection? The number of lymph nodes resected in sentinel and axillary lymph node dissections.
abstract: OBJECTIVE
  We sought to compare the number of lymph nodes (LN) resected in axillary lymph node dissections (ALND) and sentinel lymph node dissections (SLND), and to assess the validity of registry reporting for axillary staging in breast cancer.
  
  
  METHODS
  Women in the California Cancer Registry who underwent surgical axillary staging for T1/T2, M0 breast cancer between 2004 and 2008 were evaluated. The number of LN resected in patients reported as having SLND+ALND and ALND were assessed for compliance with 6 and 10 LN threshold definitions for ALND. The proportion of patients with ≤3 LN removed was assessed for patients receiving SLND only.
  
  
  RESULTS
  Of 71,907 patients, 45.5 % had SLND, 24.0 %, SLND+ALND, and 30.5 %, ALND. The median number of LN resected with SLND cases was 2 (range 1-41); SLND+ALND, 9 (range 1-63); and ALND, 11 (range 1-81) (p < 0.0001). Of patients undergoing ALND, 56.7 % had ≥10 LN removed; 46.2 % of patients with SLND+ALND had ≥10 LN removed (p < 0.0001). Overall, 75.5 % of patients with ALND had ≥6 LN removed and 67.8 % of patients with SLND+ALND had ≥6 LN removed (p < 0.0001). Of those receiving only SLND, 83.4 % had ≤3 LN removed.
  
  
  CONCLUSIONS
  A significant proportion of patients did not meet the minimum LN count thresholds for full ALND or had excess LN removed in a SLND. Further investigation is required to determine whether absolute LN number or reported operative procedure and implied surgical technique better defines axillary staging in a registry database.
authors.affiliation: Division of Surgical Oncology, Department of Surgery, Loma Linda University School of Medicine, Loma Linda, CA, USA.
authors.forename: Windy
authors.initials: W
authors.lastname: Olaya
authors.forename: Jasmine
authors.initials: J
authors.lastname: Wong
authors.forename: Jan
authors.initials: J
authors.lastname: Wong
authors.forename: John
authors.initials: J
authors.lastname: Morgan
authors.forename: Kevork
authors.initials: K
authors.lastname: Kazanjian
authors.forename: Sharon
authors.initials: S
authors.lastname: Lum
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology / Q000601:surgery*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D021701:Sentinel Lymph Node Biopsy; D055815:Young Adult