title: Can irradiation of potential cancer stem-cell niche in the subventricular zone influence survival in patients with newly diagnosed glioblastoma?
abstract: Glioblastoma progenitor or stem cells residing in the stem-cell niche in the subventricular zones (SVZ) can initiate or promote tumorigenesis. They can also migrate throughout the brain, resulting in disease progression. Irradiation of potential cancer stem-cell niche in the SVZ may influence survival. To analyze radiotherapy dose-volume parameters to the SVZ that correlate with survival in adequately treated patients with newly diagnosed glioblastoma, 40 adults with histopathologically proven supratentorial glioblastoma with available baseline imaging treated with postoperative conventionally fractionated focal conformal radiotherapy plus chemotherapy, available radiotherapy planning dataset, and documented event of progression or death or minimum 6-month follow-up were included in this retrospective study. Dose-volume parameters to the SVZ were extracted from treatment planning system and analyzed in relation to survival outcomes. Mean ipsilateral and contralateral SVZ volumes were 5.6 and 6.4 cc, respectively. With median follow-up of 15 months (interquartile range 12-18 months), median [95 % confidence interval (CI)] progression-free survival (PFS) and overall survival (OAS) was 11 months (95 % CI 8.9-13.0 months) and 17 months (95 % CI 11.6-22.4 months), respectively. Older age (>50 years), poor recursive partitioning analysis (RPA) class, and higher than median of mean contralateral SVZ dose were associated with significantly worse PFS and OAS. Multivariate analysis identified RPA class, Karnofsky performance status, and mean ipsilateral SVZ dose as independent predictors of survival. Increasing mean dose to the ipsilateral SVZ was associated with significantly improved OAS. Irradiation of potential cancer stem-cell niche influences survival outcomes in patients with newly diagnosed glioblastoma.
authors.affiliation: Department of Radiation Oncology, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC) and Tata Memorial Hospital, Tata Memorial Centre, Kharghar, Navi Mumbai, 410210, India. tejpalgupta@rediffmail.com
authors.forename: Tejpal
authors.initials: T
authors.lastname: Gupta
authors.forename: Vimoj
authors.initials: V
authors.lastname: Nair
authors.forename: Siji Nojin
authors.initials: SN
authors.lastname: Paul
authors.forename: Sadhana
authors.initials: S
authors.lastname: Kannan
authors.forename: Aliasgar
authors.initials: A
authors.lastname: Moiyadi
authors.forename: Sridhar
authors.initials: S
authors.lastname: Epari
authors.forename: Rakesh
authors.initials: R
authors.lastname: Jalali
mesh_terms: D000293:Adolescent; D000328:Adult; D001932:Brain Neoplasms / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D002552:Cerebral Ventricles / Q000473:pathology / Q000528:radiation effects*; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D005909:Glioblastoma / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000473:pathology / Q000528:radiation effects*; D011379:Prognosis; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies; D055153:Stem Cell Niche / Q000528:radiation effects*; D015996:Survival Rate; D055815:Young Adult