The added value of concurrently administered temozolomide versus adjuvant temozolomide alone in newly diagnosed glioblastoma.
OBJECTIVE
Temozolomide (TMZ), given concurrently with radiotherapy (RT) and as adjuvant monotherapy afterwards, has led to improved survival in glioblastoma multiforme (GBM). However, it is unclear whether its primary mechanism of action is through enhancement of radiation response, independent cytotoxicity, or both. We sought to determine the relative contribution of concomitant temozolomide in patients treated by concurrent and adjuvant TMZ versus adjuvant TMZ alone in the setting of newly diagnosed GBM.


METHODS
We identified patients diagnosed with GBM and treated with surgery, involved-field radiotherapy, and chemotherapy at MGH between 2002 and 2004. Eligible patients received either adjuvant temozolomide alone (group 1) or temozolomide concurrently with RT followed by adjuvant TMZ (group 2). The primary endpoint of this retrospective analysis was overall survival (OS).


RESULTS
Forty-three patients (group 1, n = 21; group 2, n = 22) were included in this study. The median follow-up was 33.7 months for surviving patients. There were no significant differences in baseline characteristics between these two groups. On univariate analysis, patients who received concurrent and adjuvant temozolomide experienced a 2-year OS of 51% and median survival of 25.5 months, compared with a 2-year OS of 36% and median survival of 15.6 months for group 1 patients (P < 0.05). On multivariable analysis, the hazard ratio (HR) favoring concurrent TMZ trended towards significance (HR = 0.51, P = 0.08) despite modest patient numbers.


CONCLUSIONS
Concurrent and adjuvant TMZ was associated with improved survival compared to adjuvant TMZ alone, highlighting the potentiation of radiation effect by temozolomide in the clinical setting.
Sher
David J
DJ
Harvard Radiation Oncology Program, Boston, MA, USA.
Henson
John W
JW
Avutu
Bindu
B
Hochberg
Fred H
FH
Batchelor
Tracy T
TT
Martuza
Robert L
RL
Barker
Fred G
FG
Loeffler
Jay S
JS
Chakravarti
Arnab
A
D000328:Adult; D000368:Aged; D018906:Antineoplastic Agents, Alkylating / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D024221:Antineoplastic Protocols; D001932:Brain Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003131:Combined Modality Therapy; D003606:Dacarbazine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005909:Glioblastoma / Q000188:drug therapy* / Q000532:radiotherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012189:Retrospective Studies; D015983:Selection Bias; D016019:Survival Analysis; D000077204:Temozolomide
D018906:Antineoplastic Agents, Alkylating; D003606:Dacarbazine; D000077204:Temozolomide