ESTRO 2024 - Abstract Book

S969

Clinical - CNS

ESTRO 2024

1 University of Florence, Radiation Oncology Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. 2 University of Florence, Pathology Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy. 3 University of Florence, NNeurosurgery Unit, Azienda Ospedaliero Universitaria Careggi, Florence, Italy

Purpose/Objective:

Median survival in patients with glioblastoma (GBM) usually is in the range of 12 months. Only few patients survive longer, and the 5-year survival rate is still 5 – 10%. Patient and disease features associated with long-term survival remain poorly defined. Aim of this study was to assess the clinical trajectory as well as the clinical and molecular characteristics in an homogeneous cohort of long-term GBM survivors treated at the University of Florence (UNIFI).

Material/Methods:

Patients with glioblastoma surviving at least 5 years from diagnosis were identified at Unifi. In patients with isocitrate dehydrogenase (IDH) wildtype tumours, prognostic factors were analysed using the Kaplan-Meier method.

Results:

39 GBM long-term survivors were identified. 24 Males (61.5%) and 15 females (38.5%). Mean age at the time of diagnosis was 52 years (range 37-74). KPS was < 80 in 9 patients (23%) and >80 in 30 patients (77%) respectively). 37 patients presented with a unifocal disease and 2 patients with a multifocal disease. Gross total resection was achieved in 36 patients (93.3%) while in 3 patients (7.7%) a biopsy was performed. All patients were diagnosed according to the CNS WHO 2021 5th edition as follows: IDH-wildtype in 31 pts (79.5%); IDH-mut in 8 pts (20.5%); In 7 patients we have acknowledged the mutation which is IDH1 p.R132H in 4 patients, p.G105G in 2 patients and IDH2 p.R172K in 1 patient. Necrosis was absent in 9 patients (23%) and present in 30 patients (77%). Vascular proliferation was absent in 10 patients (25.6%) and present in 29 patients (74.4%). MGMT status was unmethylated in 11 patients (28.2%) and methylated in 28 patients (71.8%). p53 H-score was <20 in 13 patients (33.3%) and >20 in 26 patients (66.7%) respectively. Adjuvant radio-chemotherapy with temozolomide (TMZ) according to Stupp protocol was performed in all 39 patients (100%) with a median of 12 cycles of sequential TMZ (95% CI 9-17), arithmetic mean 13.2 cycles (95% CI 10.6-15.8). 30 (77%) patients recurred the 1st time, those recurrences were treated as follows: Surgery in 2 patients; chemotherapy (CT) alone in 12 patients, re-irradiation (re-RT) alone in 2 patients, CT+re-RT in 8 patients, Bevacizumab alone in 3 patients, CT + Beva in 1 patients, re-RT + Beva in 1 patient. Among the 30 relapsed patients, 22 had a second relapse and those recurrences were treated as follows: TT alone in 10 patients, CT + re-RT in 1 patient, Bevacizumab alone in 2 patients, CT + Beva in 2 patients, while 9 patients did not receive any further treatment. Finally, 6 patients experienced a third recurrence and those recurrences were treated with: CT alone in 2 patients, Bevacizumab alone in 2 patients, CT + Beva in 1 patient, re-RT + Beva in 1 patient while 1 patient did not receive treatment. Median PFS was 32,1 months (95% CI: 25,590-46) (Fig.1)