Comparative study between hypo-fractionated simultaneous integrated boost-intensity modulated radiotherapy combined with Temozolomide versus 3D conformal radiotherapy combined with Temozolomide in treatment of Glioblastoma Multiforme

Abstract

Author(s): Manar M Elzayat*, Hanan Shawky Mahmoud, Lamiss Mohamed Abd Aziz and Radwa A Awad

Background: Glioblastoma Multiform (GBM) is the most common primary brain tumor in adults representing the most common diffuse glioma. The aim of this work is to evaluate patients' characteristics of both treatment groups Simultaneous Integrated Boost-Intensity Modulated Radiotherapy (SIB-IMRT) with Temozolomide (TMZ) vs. standard Three-Dimensional Conformal Radiation Therapy (3DCRT) with TMZ, compare the therapeutic index of treatment and Dosimetric differences of 3DCRT plans to that of SIB-IMRT in GBM patients.

Methods: This prospective hospital-based study was carried out on 40 patients at clinical oncology department, Tanta University Hospitals, Egypt. Patients aged ≥ 18 years old, both sexes, newly with diagnosed GBM, performance status 0-2, adequate hematological, liver and renal functions. Patients were divided into two equal groups: Group A: treated with doses of 2.4 GY, 2.2 GY, and 2.0 GY daily in 27 fractions with conformal a total dose of 64.8 GY, 59.4 GY, 54GY, using SIB-IMRT and group B: treated with 3D Radiation Therapy (3DCRT) with doses of 60 GY in 30 fractions, 2 GY per fraction, daily five days a week.

Results: Demographic data were insignificantly different between both groups while there was statistically significant difference dosimetrically between the two groups (p<0.05) including brain stem, optic nerve, optic chiasm, cochlea, lens and eyes. In group A mean PTV 95% dose was 63.5 GY ± 0.648 GY that covered by 98% of total dose ± 1% while in group B mean PTV 95% dose was 57.6 GY ± 1.2 GY (that covered by 96% of total dose ± 2%) which were statically significant (P<0.05). Regarding survival, median PFS was higher in group A than group B, but it was insignificant (p=0.306), 1-year PFS for group A was 90.0% while it was 75.5% for group B. Median OS was 20 months and 16 months for IMRT-SIB arm and 3D RT arm respectively, OS at 1 and 2-year were 95.0%, 38.6% for group A respectively and 70.0%, 12.1% respectively for group B with statistically significant difference (P=0.002). Toxicities (Non hematological and hematological) were nearly same in the two groups.

Conclusions: Hypo fractionated SIB-IMRT combined with temozolomide appears to be safe as well as effective line of treatment in patients with GBM. It implements dose escalation with hypo-fractionation protocols (SIB-IMRT), with improving survival without increasing side effects or treatment interruptions.

Share this article