title: Fate of bilateral renal lesions missed on preoperative imaging: a report from the National Wilms Tumor Study Group.
abstract: OBJECTIVE
  In children undergoing nephrectomy for Wilms tumor exploration of the contralateral kidney has been recommended to detect occult tumors missed on preoperative evaluation. In this review of the National Wilms Tumor Study (NWTS) 4 cases of bilateral Wilms tumors (BWT) we evaluate incidence and outcome of missed bilateral lesions.
  
  
  METHODS
  NWTS-4 enrolled 3,335 patients from August 1986 through September 1994. There were 188 patients with BWT or 5.6% of the total registered. The operative records, pathology and imaging reports were reviewed.
  
  
  RESULTS
  In 11 cases synchronous BWT was diagnosed at surgical exploration, which represents 5.9% of the bilateral cases but only 0.3% of all NWTS-4 cases. Two patients did not undergo preoperative imaging and were excluded from analysis. The size of the missed lesions was less than 1 cm in 6 patients and 1 to 2 cm in 3. Computerized tomography was performed in all patients except one who entered early in the study. Management of missed lesions included enucleation in 2 cases, biopsy in 6 and no surgery in 1. No patient underwent irradiation. The postoperative chemotherapy regimen consisted of doxorubicin, dactinomycin and vincristine in 6 children, and dactinomycin and vincristine in 3. Median followup was 9 years. There were no recurrences in any kidney with a missed lesion. All 9 patients were alive and disease-free at last followup.
  
  
  CONCLUSIONS
  Routine contralateral renal exploration will identify few occult tumors not detected on preoperative imaging. Omission of routine exploration will not likely affect the outcome or management of newly diagnosed Wilms tumor provided preoperative computerized tomography or magnetic resonance imaging is performed. The outcome in these patients was excellent.
authors.affiliation: Division of Urology, University of Texas Houston Medical School, Houston, Texas, USA. michael.ritchey@gmail.com
authors.forename: Michael L
authors.initials: ML
authors.lastname: Ritchey
authors.forename: Robert C
authors.initials: RC
authors.lastname: Shamberger
authors.forename: Thomas
authors.initials: T
authors.lastname: Hamilton
authors.forename: Gerald
authors.initials: G
authors.lastname: Haase
authors.forename: Pedram
authors.initials: P
authors.lastname: Argani
authors.forename: Susan
authors.initials: S
authors.lastname: Peterson
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D003609:Dactinomycin / Q000008:administration & dosage; D018572:Disease-Free Survival; D004317:Doxorubicin / Q000008:administration & dosage; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery*; D016609:Neoplasms, Second Primary / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery*; D009392:Nephrectomy; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014750:Vincristine / Q000008:administration & dosage; D009396:Wilms Tumor / Q000175:diagnosis* / Q000188:drug therapy / Q000601:surgery*
chemical_list: D003609:Dactinomycin; D014750:Vincristine; D004317:Doxorubicin