title: Influence of incidental radiation dose in the subventricular zone on survival in patients with glioblastoma multiforme treated with surgery, radiotherapy, and temozolomide.
abstract: OBJECTIVE
  To determine if there is an association between the incidental radiation dose to the subventricular zone and survival in patients with glioblastoma multiforme treated with surgery, radiotherapy and temozolomide.
  
  
  METHODS
  Sixty-five patients, treated between 2006 and 2015, were included in this retrospective study. The doses (75th percentile; p75) administered to the ipsilateral, contralateral and bilateral subventricular zone were compared to overall survival and progression-free survival using Cox proportional hazards models. Covariates included: age, sex, surgery, tumor location, and concomitant and adjuvant temozolomide.
  
  
  RESULTS
  Median progression-free survival and overall survival were 11.5 ± 9.96 and 18.8 ± 18.5 months, respectively. The p75 doses to the ipsilateral, contralateral and bilateral subventrivular zone were, respectively, 57.30, 48.8, and 52.7 Gy. Patients who received a dose ≥48.8 Gy in the contralateral subventricular zone had better progression-free survival than those who received lower doses (HR 0.46; 95% CI 0.23-0.91 P = 0.028). This association was not found for overall survival (HR 0.60; 95% CI 0.30-1.22 P = 0.16). Administration of adjuvant temozolomide was significantly associated with improved progression-free survival (HR 0.19; 95% CI 0.09-0.41 P < 0.0001) and overall survival (HR 0.11; 95% CI 0.05-0.24 P = 0.001). In the subgroup of 46 patients whose O6-methylguanine-DNA methyltransferase gene promoter status was known, the methylation had no effect on either progression-free survival (P = 0.491) or overall survival (P = 0.203).
  
  
  CONCLUSIONS
  High-dose radiation in the contralateral subventricular zone was associated with a significant improvement in progression-free survival but not overall survival in patients treated for glioblastoma multiforme.
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain. pforo@parcdesalutmar.cat.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain. pforo@parcdesalutmar.cat.|Universitat Pompeu Fabra, Barcelona, Spain. pforo@parcdesalutmar.cat.
authors.forename: P
authors.initials: P
authors.lastname: Foro Arnalot
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.|Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: O
authors.initials: O
authors.lastname: Pera
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.|Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Rodriguez
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.|Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: X
authors.initials: X
authors.lastname: Sanz
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Reig
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Membrive
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Ortiz
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Granados
authors.affiliation: Department of Radiation Oncology, Parc de Salut Mar, Sant Josep de la Montanya 12, 08024, Barcelona, Spain.|IMIM (Hospital del Mar Medical Research Institute), Carrer del Dr. Aiguader, 88, 08003, Barcelona, Spain.|Universitat Pompeu Fabra, Barcelona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Algara
mesh_terms: D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D003131:Combined Modality Therapy; D003606:Dacarbazine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000401:mortality* / Q000473:pathology / Q000628:therapy; D006801:Humans; D020547:Lateral Ventricles / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011829:Radiation Dosage; D012189:Retrospective Studies; D015996:Survival Rate; D000077204:Temozolomide
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide
keywords: Glioblastoma; Radiotherapy; Subventricular zone