ESTRO 2021 Abstract Book

S857

ESTRO 2021

1 University Hospital Juan Ramon Jimenez, Huelva, Spain, Comprehensive Care Department Cancer- Radiation Oncology Service Huelva, Spain, Huelva, Spain

Purpose or Objective GBM (glioblastoma multiforme) is the most common primary CNS malignancy. The optimal treatment for elderly and/or ECOG (Eastern Cooperative Oncology Group) > 1 is certainly unknown. This study describes outcomes of Stupp protocol radiotherapy (60Gy/30fx) with concomitant and with/without six months maintenance temozolomide (TMZ) and hypofractionated RT (40 Gy/15fx) with/without chemotherapy in GBM in terms of toxicities and overall survival. Besides, we try to identify any cancer or treatment prognostic factor Materials and Methods Fifty-five patients included in the study were treated between 2013-2020 for GBM in our Hospital. 18% underwent biopsy, 47% partial and 35% gross total resection of the brain tumor. 62% (34 patients) were treated with Stupp protocol and 38% (21 patients) were treated with RT 60Gy+TMZ without maintenance TMZ or 40 Gy with/without chemotherapy. Patients older than 65 years or ECOG > 1 who underwent biopsy or surgery for GBM and adjuvant therapies were included in this study. We monitor acute toxicities of CTCAE v4 closely during and after treatment. We analyzed the overall survival (mOS) by the Kaplan-Meier method and selected prognostic variables using the multivariate analysis (MVA). Results 56 patients (51% female, 49% male) with a median age of 60 years (33-82 years); 29% > 65 years, 11% ECOG > 1 and 3.5% both things. A median ECOG before adjuvant therapy of 0 (0-2) met the criteria. 53% with IDH wild type, 6% with positive mutation and 41% unknown. Multifocal type was in 9 patients. Median size was 4.5 cm. Median time-gap from surgery to initiation of CRT was 7 weeks. No patients with acute toxicity grade III or IV of CTCAE v4. 80% with asthenia grade I-II, 65% with queasiness grade I-II and 35% with myelotoxicity grade I-II. Median overall survival (mOS) of the entire group was 12.7 months, mOS of the Stupp group was 11.3 months and non-Stupp group was 7.4 months 62% of patients underwent RT with Stupp protocol (mOS 11.3 months); 9% started Stupp protocol but without TMZ maintenance due to progression (mOS 3.6 months); 9% were treated with 40 Gy RTE with concomitant either maintenance TMZ (mOS 8.4 months); 11% were treated with 40 Gy RTE with concomitant but without maintenance TMZ (mOS 8 months); 9% were treated with 40 Gy RTE scheme without concomitant neither maintenance TMZ (mOS 5.9 months). We observed that administration of maintenance TMZ and ECOG < 1 were the variables related to a better survival (p 0.048 and p 0.024, respectively). Moreover, we observed that old age, the use of the steroid therapy and multifocal tumor were related to a worst OS (p 0.008, p 0.002 and p 0.021, respectively).