title: The significance of serial histopathology in a residual mass for outcome of intermediate risk stage 3 neuroblastoma.
abstract: BACKGROUND
  To describe the serial histopathology of intermediate risk stage 3 neuroblastoma after chemotherapy, and correlate with residual mass at therapy completion and outcome.
  
  
  METHODS
  A retrospective review of intermediate risk stage 3 neuroblastoma patients treated 1989-2005 at Children's Hospital Los Angeles according to CCG 3881 or CCG 3961 protocols was performed, with central review of histopathology, radiology, and surgery.
  
  
  RESULTS
  Eighteen patients treated per CCG 3881 (n = 9) or CCG 3961 (n = 9), with including 1 (n = 5), 2 (n = 9), ≥ 3 (n = 3), or unknown number (n = 1) of surgical procedures were included. At therapy completion, 10 patients had residual tumor: <10% original size (n = 3), >10% original size (n = 6) (5 MIBG avid; 4 with elevated catecholamines), and CT non-measurable MIBG avid tumor (n = 1). Post-chemotherapy histology showed tumor regression (n = 4); or maturation with (n = 6) or without (n = 2) Schwannian development. Histologic changes correlated with median tumor shrinkage of 80% (regressing tumors) and <25% (maturing tumors). Tumor size increased in one patient with maturing tumor and Schwannian development. Overall survival was 100%.
  
  
  CONCLUSIONS
  Post-chemotherapy histopathology of intermediate risk stage 3 neuroblastoma was characterized by regression or maturation. Persisting residual and maturing tumors were not associated with tumor progression, despite MIBG uptake and/or elevated catecholamines, supporting observation only. Histopathology should be obtained in future studies to confirm these findings, and guide length of chemotherapy.
authors.affiliation: Department of Pediatrics, Children's Hospital Los Angeles, USC Keck School of Medicine, Los Angeles, California, USA. amarachelian@chla.usc.edu
authors.forename: Araz
authors.initials: A
authors.lastname: Marachelian
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimada
authors.forename: Hideki
authors.initials: H
authors.lastname: Sano
authors.forename: Hollie
authors.initials: H
authors.lastname: Jackson
authors.forename: James
authors.initials: J
authors.lastname: Stein
authors.forename: Richard
authors.initials: R
authors.lastname: Sposto
authors.forename: Katherine K
authors.initials: KK
authors.lastname: Matthay
authors.forename: David
authors.initials: D
authors.lastname: Baker
authors.forename: Judith G
authors.initials: JG
authors.lastname: Villablanca
mesh_terms: D002675:Child, Preschool; D006801:Humans; D007223:Infant; D009367:Neoplasm Staging; D009447:Neuroblastoma / Q000401:mortality / Q000473:pathology* / Q000628:therapy; D012189:Retrospective Studies