title: Prognostic values of initial responses to low-dose (131)I-MIBG therapy in patients with malignant pheochromocytoma and paraganglioma.
abstract: OBJECTIVE
  We retrospectively examined whether or not initial responses of first low-dose (131)I-meta-iodo-benzyl-guanidine radiotherapy ((131)I-MIBG therapy) in patients with malignant pheochromocytoma and paraganglioma had prognostic values.
  
  
  METHODS
  This study included 26 patients with malignant pheochromocytoma (n = 18) and paraganglioma (n = 8) who underwent the first (131)I-MIBG therapy between October 2001 and September 2007. Based on the initial subjective, hormonal, scintigraphic, and objective responses to (131)I-MIBG therapy, the responses were divided into progression disease (PD) and non-PD. We examined the following factors for prognostic significance: sex, age, disease, initial diagnosis (benign or malignant pheochromocytoma), hypertension, diabetes mellitus, palpitations, symptoms related to bone metastases, and number of low-dose (131)I-MIBG therapy. Univariate Cox proportional regression analysis was used to identify prognostic factors for overall survival. Overall survival was analyzed by Kaplan-Meier method and the curves were compared using the log-rank test.
  
  
  RESULTS
  The median survival time was 56 months. In the follow-up period, 16 patients died from exacerbation of their diseases. Univariate analysis showed that the hormonal PD [hazard ratio (HR) 3.20, P = 0.034, confidence interval (CI) 1.09-9.93], objective PD (HR 11.89, P = 0.0068, CI 2.14-65.85), single-time (131)I-MIBG therapy (HR 3.22, P = 0.020, CI 1.21-8.79), hypertension (HR 2.93, P = 0.044, CI 1.02-10.50), and symptoms related to bone metastases (HR 3.54, P = 0.023, CI 1.18-13.04) were bad prognostic factors for overall survival. Kaplan-Meier analysis demonstrated that the hormonal non-PD (P = 0.026), objective non-PD (P = 0.0002), multiple-time (131)I-MIBG therapy (P = 0.013), and no symptom related to bone metastases (P = 0.024) were significantly associated with good prognosis. Overall survival rate was 70 and 50 % at 5 years from the initial diagnosis and from the first (131)I-MIBG therapy, respectively.
  
  
  CONCLUSIONS
  The hormonal and objective responses to the first low-dose (131)I-MIBG therapy as well as complication of hypertension and symptoms related to bone metastases may be prognostic factors in patients with malignant pheochromocytoma and paraganglioma.
authors.affiliation: Department of Nuclear Medicine, Kanazawa University Hospital, 13-1 Takara-machi, Kanazawa, Ishikawa, 920-8641, Japan, wakabayashi@nmd.m.kanazawa-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Wakabayashi
authors.forename: Junichi
authors.initials: J
authors.lastname: Taki
authors.forename: Anri
authors.initials: A
authors.lastname: Inaki
authors.forename: Ayane
authors.initials: A
authors.lastname: Nakamura
authors.forename: Daiki
authors.initials: D
authors.lastname: Kayano
authors.forename: Makoto
authors.initials: M
authors.lastname: Fukuoka
authors.forename: Shinro
authors.initials: S
authors.lastname: Matsuo
authors.forename: Kenichi
authors.initials: K
authors.lastname: Nakajima
authors.forename: Seigo
authors.initials: S
authors.lastname: Kinuya
mesh_terms: D019797:3-Iodobenzylguanidine / Q000627:therapeutic use*; D000310:Adrenal Gland Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010235:Paraganglioma / Q000175:diagnosis / Q000532:radiotherapy*; D010673:Pheochromocytoma / Q000175:diagnosis / Q000532:radiotherapy*; D011379:Prognosis; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D019797:3-Iodobenzylguanidine