Comparative study of six cycles versus twelve cycles of adjuvant temozolomide post concurrent chemoradiation in newly diagnosed glioblastoma.
e13034 Background: This study assesses the impact of 6 cycles of adjuvant TMZ (conventional arm) versus 12 cycles (Extended arm) on Progression free survival (PFS), evaluate the toxicity and correlate the outcome with EGFR, P53 and MIB I labelling Index. Methods: Between December 2010 to October 2012, 36 post operative patients of Glioblastoma between age 18-65 years and Karnofsky Performance Score (KPS) ≥ 70 were included. Patients were randomized to receive Radiation with a dose of 60 Gray in 30 fractions over 6 weeks at 2 gray/fraction with concomitant TMZ (75 mg/m2/day) and Adjuvant therapy with either 6 or 12 cycles of TMZ(150 mg/m2 for 5 days, 28 days cycle). Patients were then assessed monthly clinically and imaged with MRI/CT every 3 monthly or when symptomatic. Toxicity was assessed using CTCAE version 3.0. Statistical Analysis was done using SPSS version 17.0.Kaplan Meier method was used for analysis of survival and log rank test was used for assessing the impact of variables on survival. Results: Of 36 patients, 18 patients were treated in each arm. Median age and KPS in both the arms was 47 years and 80 respectively. 44 % patients in the conventional arm and 50% patients in the Extended arm underwent complete surgical resection. 22% patients in the conventional arm and 28% in the extended arm did not complete their intended treatment. Grade ¾ Thrombocytopenia was seen in 16% in the extended arm and 0% in the conventional arm.EGFR, P 53 and MIB 1 >20% was seen in 26%, 45% and 20% patients respectively, overall. Median follow up was 18 months for both the arms (Range 10-23 months).At last follow up,8 patients in each arm had progression. Median PFS was 10 months vs.18.4 months (p 0.47) in conventional and extended arm respectively. On Univariate analysis, patients with KPS ≤ 80 had poorer survival than those >80 (Median PFS 9.5 Months vs. 16.9 Months; p 0.02).Age, extent of resection, EGFR, P53, MIB 1 did not significantly alter survival in the two treatment groups. Conclusions: Our study showed that schedule of extended Temozolomide is well tolerated by patients and tend to have better progression free survival. Further prospective randomized studies are needed to validate the findings of our study.