title: Occult pelvic lymph node involvement in bladder cancer: implications for definitive radiation.
abstract: OBJECTIVE
  To inform radiation treatment planning for clinically staged, node-negative bladder cancer patients by identifying clinical factors associated with the presence and location of occult pathologic pelvic lymph nodes.
  
  
  METHODS
  The records of patients with clinically staged T1-T4N0 urothelial carcinoma of the bladder undergoing radical cystectomy and pelvic lymphadenectomy at a single institution were reviewed. Logistic regression was used to evaluate associations between preoperative clinical variables and occult pathologic pelvic or common iliac lymph nodes. Percentages of patient with involved lymph node regions entirely encompassed within whole bladder (perivesicular nodal region), small pelvic (perivesicular, obturator, internal iliac, and external iliac nodal regions), and extended pelvic clinical target volume (CTV) (small pelvic CTV plus common iliac regions) were calculated.
  
  
  RESULTS
  Among 315 eligible patients, 81 (26%) were found to have involved pelvic lymph nodes at the time of surgery, with 38 (12%) having involved common iliac lymph nodes. Risk of occult pathologically involved lymph nodes did not vary with clinical T stage. On multivariate analysis, the presence of lymphovascular invasion (LVI) on preoperative biopsy was significantly associated with occult pelvic nodal involvement (odds ratio 3.740, 95% confidence interval 1.865-7.499, P<.001) and marginally associated with occult common iliac nodal involvement (odds ratio 2.307, 95% confidence interval 0.978-5.441, P=.056). The percentages of patients with involved lymph node regions entirely encompassed by whole bladder, small pelvic, and extended pelvic CTVs varied with clinical risk factors, ranging from 85.4%, 95.1%, and 100% in non-muscle-invasive patients to 44.7%, 71.1%, and 94.8% in patients with muscle-invasive disease and biopsy LVI.
  
  
  CONCLUSIONS
  Occult pelvic lymph node rates are substantial for all clinical subgroups, especially patients with LVI on biopsy. Extended coverage of pelvic lymph nodes up to the level of the common iliac nodes may be warranted in subsets of patients.
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Goldsmith
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Baumann
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Jiwei
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Kai
authors.initials: K
authors.lastname: Tucker
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Justin
authors.initials: J
authors.lastname: Bekelman
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Curtiland
authors.initials: C
authors.lastname: Deville
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Neha
authors.initials: N
authors.lastname: Vapiwala
authors.affiliation: Department of Medical Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: David
authors.initials: D
authors.lastname: Vaughn
authors.affiliation: Department of Medical Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Keefe
authors.affiliation: Department of Urology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guzzo
authors.affiliation: Department of Urology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: S Bruce
authors.initials: SB
authors.lastname: Malkowicz
authors.affiliation: Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: christojo@uphs.upenn.edu.
authors.forename: John P
authors.initials: JP
authors.lastname: Christodouleas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002295:Carcinoma, Transitional Cell / Q000532:radiotherapy* / Q000556:secondary / Q000601:surgery; D015653:Cystectomy / Q000379:methods; D005260:Female; D006801:Humans; D016015:Logistic Models; D008197:Lymph Node Excision / Q000379:methods / Q000592:standards; D008198:Lymph Nodes / Q000473:pathology*; D015182:Lymphatic Irradiation / Q000379:methods*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D010388:Pelvis; D012307:Risk Factors; D001749:Urinary Bladder Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery