title: Does failure to visualize a sentinel node on preoperative lymphoscintigraphy predict a greater likelihood of axillary lymph node positivity?
abstract: BACKGROUND
  Sentinel lymph node (SLN) mapping has become the standard of care for axillary staging in women with early-stage breast cancer. The purpose of the study was to investigate the hypothesis that nonvisualization of SLN on lymphoscintigraphy (LSG) predicts a subset of patients at risk of having a substantial burden of axillary tumor as evidenced by higher rate of lymph node involvement.
  
  
  METHODS
  We retrospectively reviewed the records of 1,500 patients who underwent dual-tracer SLN mapping for breast cancer between 1999 and 2004. LSG were reported as negative or positive.
  
  
  RESULTS
  Ninety-one percent had axillary SLN(s) identified on LSG imaging. In 133 of 134 (99.3%) patients with a negative LSG, SLN(s) was identified intraoperatively either by blue dye or hand-held gamma detection. SLN was positive in 28.4% of LSG nonvisualized group and was positive in 29.1% of LSG visualized group (p>0.05). A significantly higher percentage of women older than 50 years of age had nonvisualization of SLN (p<0.0001). Body mass index (calculated as kg/m2) was >30 in 42.5% of LSG nonvisualized group and in 26.3% in LSG visualized group (p<0.0001).
  
  
  CONCLUSIONS
  Failure to demonstrate axillary uptake by LSG appears to be related to technical factors and patient-related factors, such as body mass index and older age, but does not adversely affect SLN identification. The equivalent rate of positive SLNs in patients with a positive or negative LSG supports the null hypothesis that "failure to visualize" on LSG does not identify a subset of patients at higher risk of being axillary lymph node positive.
authors.affiliation: Department of Surgery, Magee-Womens Hospital of the University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
authors.forename: Atilla
authors.initials: A
authors.lastname: Soran
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Falk
authors.forename: Marguerite
authors.initials: M
authors.lastname: Bonaventura
authors.forename: Donald
authors.initials: D
authors.lastname: Keenan
authors.forename: Gretchen
authors.initials: G
authors.lastname: Ahrendt
authors.forename: Ronald
authors.initials: R
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy