title: Relationship between survival and increased radiation dose to subventricular zone in glioblastoma is controversial.
abstract: To test the hypothesis on prolonged survival in glioblastoma cases with increased subventricular zone (SVZ) radiation dose. Sixty glioblastoma cases were previously treated with adjuvant radiotherapy and Temozolamide. Ipsilateral, contralateral and bilateral SVZs were contoured and their doses were retrospectively evaluated. Median follow-up, progression free survival (PFS) and overall survival (OS) were 24.5, 8.5 and 19.3 months respectively. Log-rank tests showed a statistically significant correlation between contralateral SVZ (cSVZ) dose > 59.2 Gy (75th percentile) and poor median PFS (10.37 [95% CI 8.37-13.53] vs 7.1 [95% CI 3.5-8.97] months, p = 0.009). cSVZ dose > 59.2 Gy was associated with poor OS in the subgroup with subtotal resection/biopsy (HR: 4.83 [95% CI 1.71-13.97], p = 0.004). High ipsilateral SVZ dose of > 62.25 Gy (75th percentile) was associated with poor PFS in both subgroups of high performance status (HR: 2.58 [95% CI 1.03-6.05], p = 0.044) and SVZ without tumoral contact (HR: 10.57 [95% CI 2.04-49], p = 0.008). The effect of high cSVZ dose on PFS lost its statistical significance in multivariate Cox regression analysis. We report contradictory results compared to previous publications. Changing the clinical practice based on retrospective studies which even do not indicate consistent results among each other will be dangerous. We need carefully designed prospective randomized studies to evaluate any impact of radiation to SVZ in glioblastoma.
authors.affiliation: Radiation Oncology Department, Cerrahpasa Faculty of Medicine, Istanbul University, I.U. Cerrahpasa Tip Fakultesi, Radyasyon Onkolojisi A.D. - Fatih, 34098, Istanbul, Turkey. olgunelicin@gmail.com.|Inselspital, Radiation Oncology Department, University of Bern, Inselspital Klinik und Poliklinik für Radio-Onkologie, 3010, Bern, Switzerland. olgunelicin@gmail.com.
authors.forename: Olgun
authors.initials: O
authors.lastname: Elicin
authors.affiliation: Radiation Oncology Department, Cerrahpasa Faculty of Medicine, Istanbul University, I.U. Cerrahpasa Tip Fakultesi, Radyasyon Onkolojisi A.D. - Fatih, 34098, Istanbul, Turkey.
authors.forename: Ebrar
authors.initials: E
authors.lastname: Inac
authors.affiliation: Radiation Oncology Department, Sisli Etfal Teaching Hospital, Sisli Etfal Egitim Arastirma Hastanesi, Radyasyon Onkolojisi Klinigi - Sisli, 34371, Istanbul, Turkey.
authors.forename: Esengul Kocak
authors.initials: EK
authors.lastname: Uzel
authors.affiliation: Radiation Oncology Department, Cerrahpasa Faculty of Medicine, Istanbul University, I.U. Cerrahpasa Tip Fakultesi, Radyasyon Onkolojisi A.D. - Fatih, 34098, Istanbul, Turkey.
authors.forename: Songul
authors.initials: S
authors.lastname: Karacam
authors.affiliation: Radiation Oncology Department, Cerrahpasa Faculty of Medicine, Istanbul University, I.U. Cerrahpasa Tip Fakultesi, Radyasyon Onkolojisi A.D. - Fatih, 34098, Istanbul, Turkey.
authors.forename: Omer Erol
authors.initials: OE
authors.lastname: Uzel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000628:therapy*; D059248:Chemoradiotherapy; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000628:therapy*; D006801:Humans; D020547:Lateral Ventricles / Q000187:drug effects / Q000528:radiation effects*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D000077204:Temozolomide; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide