Copenhagen, Denmark
Onsite/Online

ESTRO 2022

Session Item

CNS
Poster (digital)
Clinical
Hypofractionated radiotherapy in poor prognosis patients affected by glioblastoma
Alba Fiorentino , Italy
PO-1126

Abstract

Hypofractionated radiotherapy in poor prognosis patients affected by glioblastoma
Authors:

Alba Fiorentino1, Alessia Surgo2, Ilaria Bonaparte3, Maria Paola Ciliberti2, Roberta Carbonara4, Morena Caliandro2, Fabiana Gregucci4

1General Regional Hospital F Miuli, Radiation Oncology , acquaviva delle fonti, Italy; 2General Regional Hospital F Miulli, Radiation Oncology, Acquaviva delle fonti, Italy; 3General Regional Hospital F Miulli, Radiation oncology, acquaviva delle fonti, Italy; 4General Regional Hospital F Miulli, Radiation Oncology, acquaviva delle fonti, Italy

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Purpose or Objective

Glioblastoma (GBM) is a very poor prognosis brain tumor. To date, maximal excision followed by radiochemotherapy, in 30 fractions, is the standard approach. Limited data are present in literature about hypofractionated radiotherapy (hypoRT) in GBM poor prognosis patients, other than advanced age. Thus, this retrospective study was conducted to evaluate efficacy and toxicity of hypoRT with simultaneous integrated boost (SIB) in association with temozolamide (TMZ) in this setting of patients. 


Material and Methods

GBM poor prognosis patients underwent surgery (complete, subtotal or biopsy) followed by SIB-hypoRT and concomitant/adjuvant TMZ.

The definition of poor prognostic factors other than advanced age, included KPS or RPA class, neurological symptom after surgical procedures or symptoms of mass effect, high tumor burden, unresectable or multifocal lesions, high comorbidity and potential low treatment compliance due to rapidly progressive disease.

The prescription dose was 40.05Gy (15 fractions) with a SIB of 52.5Gy (3.5Gy/fraction) on surgical cavity/residual/macroscopic disease. Volumetric Modulated Arc Therapy was performed.

Results

From July 2019 to July 2021, 30 poor prognosis patients affected by GBM were treated by SIB-hypo-RT; 25 were evaluated in the present analysis due to a minimum follow up of 6 months. The median age and KPS were 65 years and 60%, respectively. At 15 months median follow-up, 14 patients (56%) were alive: 3 (12%) showed partial treatment response, 3 (12%) with stable disease and 8 (32%) with progression disease. The median OS was 13 months (95%CI 9.8-na) and 1-year OS was 54% (95%CI 31-73%); the median PFS was 8.4 months (95%CI 5.8-11.9) and 1-year PFS was 23% (95%CI 7-44%).  No acute or late neurological side effect grade ≥ 2 were reported. Grade 3-4 hematologic toxicity occurred in 3 cases. 

Of the 17 cases of disease progression, 8 received re-irradiation followed by second line systemic therapy (regorafenib or fotemustine), 3 received regorafenib alone and 6 were evaluated for best supportive care

Seven significant variables in univariate analysis (age, RPA, multifocal tumor, resection, MGMT status, GTV and PTV) were entered into multivariable model. As a result, MGMT unmethylation (HR: 0.61, 95%CI: 0.02-13.66, p=0.05), GTV > 50cc (HR: 4.83, 95%CI0.83-27.88, p=0.01) and PTV >200cc (HR:2.14, 95%CI: 0.01-9.87, p=0.02) were significant negative prognostic factors for survival.

Six significant variables in univariate analysis (mass effect, multifocal tumor, surgery, resection, MGMT status and PTV) were entered into multivariable model. As a result, multifocal tumor (p=0.05), incomplete resection (p=0.01), MGMT unmethylation (p=0.03) and PTV >200cc (HR:1.99, 95%CI: 0.26-5.37, p = 0.05) were significant negative prognostic factors for disease progression.


Conclusion

SIB-hypoRT associated with TMZ in poor prognosis patients affected by GBM is an effective and safe treatment. Prospective study could be warranted.