title: Radiographic size of retroperitoneal lymph nodes predicts pathological nodal involvement for patients with renal cell carcinoma: development of a risk prediction model.
abstract: OBJECTIVE
  To evaluate the ability of clinical and radiographic features to predict lymph node (pN1) disease among patients with renal cell carcinoma undergoing radical nephrectomy (RN), and to develop a preoperative risk prediction model.
  
  
  METHODS
  In all, 220 patients with preoperative computed tomography scans available for review underwent RN with lymph node dissection (LND) from 2000 to 2010. Radiographic features were assessed by one genitourinary radiologist blinded to pN status. Associations of features with pN1 disease were evaluated using logistic regression to develop predictive models. Model performance was assessed using area under the receiver operating characteristic curve (AUC) and decision curve analysis.
  
  
  RESULTS
  The median (interquartile range) lymph node yield was 10 (5-18). In all, 55 patients (25%) had pN1 disease at RN. On univariable analysis, the maximum lymph node (LN) short axis diameter [odds ratio (OR) 1.17; P < 0.001] predicted pN1 disease with an AUC of 0.84. Although several clinical and radiographic features were associated with pN1 disease, only two were retained in the multivariable model: maximum LN short axis diameter (OR 1.19; P <0.001) and radiographic perinephric/sinus fat invasion (OR 44.64; P = 0.01), with an AUC of 0.85. On decision curve analysis, the single variable and multivariable models showed similar net benefit.
  
  
  CONCLUSIONS
  Two radiographic features, maximum LN short axis diameter and perinephric/sinus fat invasion, outperformed traditional clinical variables in predicting pN1 disease. Maximum LN short axis diameter alone showed excellent predictive performance, and, if validated externally, would provide for a simple model to guide patient selection for LND.
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Boris
authors.initials: B
authors.lastname: Gershman
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Naoki
authors.initials: N
authors.lastname: Takahashi
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Moreira
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Thompson
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Boorjian
authors.affiliation: Department of Health Sciences Research, Mayo Clinic, Rochester, MN, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Lohse
authors.affiliation: Department of Oncology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Costello
authors.affiliation: Department of Pathology, Mayo Clinic, Rochester, MN, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Cheville
authors.affiliation: Department of Urology, Mayo Clinic, Rochester, MN, USA. Leibovich.Bradley@mayo.edu.
authors.forename: Bradley C
authors.initials: BC
authors.lastname: Leibovich
mesh_terms: D000368:Aged; D002292:Carcinoma, Renal Cell / Q000556:secondary* / Q000601:surgery; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology* / Q000601:surgery; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009392:Nephrectomy; D009929:Organ Size; D011237:Predictive Value of Tests; D012187:Retroperitoneal Space; D012189:Retrospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed
keywords: lymph node dissection; lymphadenopathy; nephrectomy; node positive; renal cell carcinoma