title: Sensitivity of surveillance studies for detecting asymptomatic and unsuspected relapse of high-risk neuroblastoma.
abstract: OBJECTIVE
  Relapse-free survival (RFS) is a powerful measure of treatment efficacy. We describe the sensitivity of standard surveillance studies for detecting relapse of neuroblastoma (NB).
  
  
  METHODS
  The patients were in complete/very good partial remission of high-risk NB; routine monitoring revealed asymptomatic and, therefore, unsuspected relapses in 113 patients, whereas 41 patients had symptoms prompting urgent evaluations. Assessments every 2 to 4 months included computed tomography, iodine-131-metaiodobenzylguanidine (131)I-MIBG; through November 1999) or iodine-123-metaiodobenzylguanidine ((123)I-MIBG) scan, urine catecholamines, and bone marrow (BM) histology. Bone scan was routine through 2002.
  
  
  RESULTS
  (123)I-MIBG scan was the most reliable study for revealing unsuspected relapse; it had an 82% detection rate, which was superior to the rates with (131)I-MIBG scan (64%; P = .1), bone scan (36%; P < .001), and BM histology (34%; P < .001). Among asymptomatic patients, (123)I-MIBG scan was the sole positive study indicating relapse in 25 (27%) of 91 patients compared with one (4.5%) of 22 patients for (131)I-MIBG scan (P = .04) and 0% to 6% of patients for each of the other studies (P < .001). Patients whose monitoring included (123)I-MIBG scan were significantly less likely than patients monitored by (131)I-MIBG scan to have an extensive osteomedullary relapse and had a significantly longer survival from relapse (P < .001) and from diagnosis (P = .002). They also had significantly longer survival than patients with symptomatic relapses (P = .002).
  
  
  CONCLUSIONS
  (123)I-MIBG scan is essential for valid estimation of the duration of RFS of patients with high-risk NB. Without monitoring that includes (123)I-MIBG scan, caution should be used when comparing RFS between institutions and protocols.
authors.affiliation: Department of Pediatrics, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, New York, NY 10065, USA. kushnerb@mskcc.org
authors.forename: Brian H
authors.initials: BH
authors.lastname: Kushner
authors.forename: Kim
authors.initials: K
authors.lastname: Kramer
authors.forename: Shakeel
authors.initials: S
authors.lastname: Modak
authors.forename: Nai-Kong V
authors.initials: NK
authors.lastname: Cheung
mesh_terms: D019797:3-Iodobenzylguanidine; D000293:Adolescent; D001853:Bone Marrow / Q000473:pathology; D001842:Bone and Bones / Q000473:pathology; D002395:Catecholamines / Q000652:urine; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging / Q000473:pathology*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology*; D009447:Neuroblastoma / Q000000981:diagnostic imaging / Q000473:pathology*; D011877:Radionuclide Imaging; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
chemical_list: D002395:Catecholamines; D007457:Iodine Radioisotopes; D019797:3-Iodobenzylguanidine