title: Incorporation of sentinel lymph node metastasis size into a nomogram predicting nonsentinel lymph node involvement in breast cancer patients with a positive sentinel lymph node.
abstract: OBJECTIVE
  Sentinel lymph node (SLN) metastasis size is an important predictor of non-SLN involvement. The goal of this study was to construct a nomogram incorporating SLN metastasis size to accurately predict non-SLN involvement in patients with SLN-positive disease.
  
  
  METHODS
  We identified 509 patients with invasive breast cancer with a positive SLN who underwent completion axillary lymph node dissection (ALND). Clinicopathologic data including age, tumor size, histology, grade, presence of multifocal disease, estrogen and progesterone receptor status, HER2/neu status, presence of lymphovascular invasion (LVI), number of SLN(s) identified, number of positive SLN(s), maximum SLN metastasis size and the presence of extranodal extension were recorded. Univariate and multivariate logistic regression analyses identified factors predictive of positive non-SLNs. Using these variables, a nomogram was constructed and subsequently validated using an external cohort of 464 patients.
  
  
  RESULTS
  On univariate analysis, the following factors were predictive of positive non-SLNs: number of SLN identified (P < 0.001), number of positive SLN (P < 0.001), SLN metastasis size (P < 0.001), extranodal extension (P < 0.001), tumor size (P = 0.001), LVI (P = 0.019), and histology (P = 0.034). On multivariate analysis, all factors remained significant except LVI. A nomogram was created using these variables (AUC = 0.80; 95% CI, 0.75-0.84). When applied to an external cohort, the nomogram was accurate and discriminating with an AUC = 0.74 (95% CI, 0.68-0.77).
  
  
  CONCLUSIONS
  SLN metastasis size is an important predictor for identifying non-SLN disease. In this study, we incorporated SLN metastasis size into a nomogram that accurately predicts the likelihood of having additional axillary metastasis and can assist in personalizing surgical management of breast cancer.
authors.affiliation: Department of Surgical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Mittendorf
authors.forename: Kelly K
authors.initials: KK
authors.lastname: Hunt
authors.forename: Judy C
authors.initials: JC
authors.lastname: Boughey
authors.forename: Roland
authors.initials: R
authors.lastname: Bassett
authors.forename: Amy C
authors.initials: AC
authors.lastname: Degnim
authors.forename: Robyn
authors.initials: R
authors.lastname: Harrell
authors.forename: Min
authors.initials: M
authors.lastname: Yi
authors.forename: Funda
authors.initials: F
authors.lastname: Meric-Bernstam
authors.forename: Merrick I
authors.initials: MI
authors.lastname: Ross
authors.forename: Gildy V
authors.initials: GV
authors.lastname: Babiera
authors.forename: Henry M
authors.initials: HM
authors.lastname: Kuerer
authors.forename: Rosa F
authors.initials: RF
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology* / Q000601:surgery*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology*; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D049451:Nomograms; D011446:Prospective Studies; D021701:Sentinel Lymph Node Biopsy; D055815:Young Adult