Post Operative Concomitant Boost Radiotherapy with Concurrent Temozolomide Followed By Adjuvant Temozolomide In Anaplastic Astrocytoma & Glioblastoma Multiforme - An Observational Study.

Abstract

Background: Gliomas are the most common primary malignant brain tumors in adults. The current standard of care for radiotherapy in GBM is focal, fractionated external beam radiation therapy (EBRT) to the surgical resection cavity and to a 2 cm margin of surrounding brain tissue. Simultaneous integrated boost (SIB) or Concomitant boost radiotherapy is an Intensity Modulated Radiation Therapy (IMRT) technique, a new way to investigate the accelerated fractionation in the definitive treatment of Gliomas and allows the planning and irradiation of different targets at different dose levels in a single treatment session.

OBJECTIVES: To assess the response of treatment, the toxicity profile of SIB-IMRT, progression-free survival, overall survival, and quality of Life (QOL).

STUDY DESIGN: Prospective- Observational Study

PARTICIPANTS: 52 Patients with Biopsy Proved grade III and IV gliomas.

METHODS: All patients were simulated on Siemens CT Simulator (Somatom) . A non-contrast scan was taken and utilized for fusion with preoperative and or postoperative MRI scans. Tumor Contouring and planning was done on Varian Eclipse software. The Gross tumor Volume (GTV) encompassed all enhancing lesion on post-gadolinium T1-weight images on MRIs, and the clinical target volume (CTV) encompassed hyperintensity area on T2-weighted fluid-attenuated inversion recovery MRI plus a 10 mm margin.

RESULTS: As per RANO criteria, complete response was observed in (30.8%) , Partial response (46.2%) stable disease (15.4%) and progression (4.4%) . Various toxicities observed includes, nausea (73.1%) , thrombocytopenia (19.2%) , vomiting in patients 15.4 %, hair loss (11.5%) , headache (7.7%) and photosensitivity (3.8%) . The mean progression-free survival was 14 months, and the mean overall survival was 13.05 months. QOL was measured with the EORTC QLQ-C30 and BN-20

CONCLUSION: SIB-IMRT is feasible and safe, with acceptable acute and late toxicities, despite the large fractional doses that were delivered to the GTV

IMPLICATIONS: SIB-IMRT can be used as a new radiation therapeutic modality in combination with novel chemotherapeutic agents in patients with high-grade gliomas. (HGG)