Incidence and outcome of pseudoprogression after radiation therapy in glioblastoma patients: A cohort study

Background

Differentiating post-radiation MRI changes from progressive disease (PD) in glioblastoma (GBM) patients represents a major challenge. The clinical problem is two-sided; avoid termination of effective therapy in case of pseudoprogression (PsP) and continuation of ineffective therapy in case of PD. We retrospectively assessed the incidence, management, and prognostic impact of PsP and analyzed factors associated with PsP in a GBM patient cohort.

Methods

Consecutive GBM patients diagnosed in the South-Eastern Norway Health Region from 2015 to 2018 who had received RT and follow-up MRI were included. Tumor, patient, and treatment characteristics were analyzed in relationship to re-evaluated MRI examinations at 3 and 6 months post-radiation using Response Assessment in Neuro-Oncology criteria.

Results

A total of 284 patients were included in the study. PsP incidence 3 and 6 months post-radiation was 19.4% and 7.0%, respectively. In adjusted analyses, methylated O6-methylguanine-DNA methyltransferase (MGMT) promoter and the absence of neurological deterioration were associated with PsP at both 3 (p < .001 and p = .029, respectively) and 6 months (p = .045 and p = .034, respectively) post-radiation. For patients retrospectively assessed as PD 3 months post-radiation, there was no survival benefit of treatment change (p = .838).

Conclusions

PsP incidence was similar to previous reports. In addition to the previously described correlation of methylated MGMT promoter with PsP, we also found that absence of neurological deterioration significantly correlated with PsP. Continuation of temozolomide courses did not seem to compromise survival for patients with PD at 3 months post-radiation; therefore, we recommend continuing adjuvant temozolomide courses in case of inconclusive MRI findings.

Astrocytoma (CNS WHO grade 4), IDH-mutant with co-occurrence of BRAF p.V600E mutation, and homozygous loss of CDKN2A

Molecular alterations nowadays play a crucial role in the diagnosis of brain tumors. Some of these alterations are associated with outcome and/or response to treatment, including sequence variants of isocitrate dehydrogenase (IDH) at position p.R132 or p.R172. Such IDH variants have so far been described in histone H3-wildtype primary brain tumors only in adult-type diffuse gliomas and are associated with a better outcome compared to their IDH-wildtype counterpart, the glioblastoma. Moreover, homozygous loss of CDKN2A and/or CDKN2B in IDH-mutant astrocytomas shortens the median overall survival regardless of histological features of malignancy. Such tumors are therefore considered to be aggressive and graded as WHO central nervous system (CNS) grade 4 lesions. The coexistence of an IDH-sequence variation and a BRAF p.V600E alteration has only rarely been described in diffuse astrocytomas. Due to the small number of cases, little is known about such neoplasms in terms of clinical behavior and response to treatment. Herein we describe the first case, to our knowledge, of an astrocytoma (CNS WHO grade 4), IDH-mutant, and BRAF p.V600E-mutant with homozygous deletion of CDKN2A. Pathologists should be aware that such an expression profile does exist even in WHO CNS grade 4 astrocytomas, IDH-mutant, and are encouraged to test for the BRAF p.V600E sequence variant as such an alteration may provide additional treatment options.

Investigating survival, quality of life and cognition in PROton versus photon therapy for IDH-mutated diffuse grade 2 and 3 GLIOmas (PRO-GLIO): a randomised controlled trial in Norway and Sweden

INTRODUCTION

The use of proton therapy increases globally despite a lack of randomised controlled trials demonstrating its efficacy and safety. Proton therapy enables sparing of non-neoplastic tissue from radiation. This is principally beneficial and holds promise of reduced long-term side effects. However, the sparing of seemingly non-cancerous tissue is not necessarily positive for isocitrate dehydrogenase (IDH)-mutated diffuse gliomas grade 2-3, which have a diffuse growth pattern. With their relatively good prognosis, yet incurable nature, therapy needs to be delicately balanced to achieve a maximal survival benefit combined with an optimised quality of life.

METHODS AND ANALYSIS

PRO-GLIO (PROton versus photon therapy in IDH-mutated diffuse grade 2 and 3 GLIOmas) is an open-label, multicentre, randomised phase III non-inferiority study. 224 patients aged 18-65 years with IDH-mutated diffuse gliomas grade 2-3 from Norway and Sweden will be randomised 1:1 to radiotherapy delivered with protons (experimental arm) or photons (standard arm). First intervention-free survival at 2 years is the primary endpoint. Key secondary endpoints are fatigue and cognitive impairment, both at 2 years. Additional secondary outcomes include several survival measures, health-related quality of life parameters and health economy endpoints.

ETHICS AND DISSEMINATION

To implement proton therapy as part of standard of care for patients with IDH-mutated diffuse gliomas grade 2-3, it should be deemed safe. With its randomised controlled design testing proton versus photon therapy, PRO-GLIO will provide important information for this patient population concerning safety, cognition, fatigue and other quality of life parameters. As proton therapy is considerably more costly than its photon counterpart, cost-effectiveness will also be evaluated. PRO-GLIO is approved by ethical committees in Norway (Regional Committee for Medical & Health Research Ethics) and Sweden (The Swedish Ethical Review Authority) and patient inclusion has commenced. Trial results will be published in international peer-reviewed journals, relevant conferences, national and international meetings and expert forums.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT05190172).

Survival in a consecutive series of 467 glioblastoma patients: Association with prognostic factors and treatment at recurrence at two independent institutions

Therapy of recurrent glioblastoma (GBM) is challenging due to lack of standard treatment. We investigated physicians' treatment choice at recurrence and prognostic and predictive factors for survival in GBM patients from Norway's two largest regional hospitals. Clinicopathological data from n = 467 patients treated at Haukeland and Oslo university hospitals from January 2015 to December 2017 was collected. Data included tumour location, promoter methylation of O6 methylguanine-DNA methyltransferase (MGMT) and mutation of isocitrate dehydrogenase (IDH), patient age, sex, extent of resection at primary diagnosis and treatment at successive tumour recurrences. Cox-proportional hazards regression adjusting for multiple risk factors was used. Median overall survival (OS) was 12.1 months and 21.4% and 6.8% of patients were alive at 2 and 5 years, respectively. Median progression-free survival was 8.1 months. Treatment at recurrence varied but was not associated with difference in overall survival (OS) (p = 0.201). Age, MGMT hypermethylation, tumour location and extent of resection were independent prognostic factors. Patients who received 60 Gray radiotherapy with concomitant and adjuvant temozolomide at primary diagnosis had 16.1 months median OS and 9.3% were alive at 5 years. Patients eligible for gamma knife/stereotactic radiosurgery alone or combined with chemotherapy at first recurrence had superior survival compared to chemotherapy alone (p<0.001). At second recurrence, combination chemotherapy with or without bevacizumab were both superior to no treatment. Treatment at recurrence differed between the institutions but there was no difference in median OS, indicating that it is the disease biology that dictates patient outcome.

SMART syndrome: two cases highlighting a complex and rare complication of brain irradiation

Stroke-like migraine attacks after radiation therapy (SMART) syndrome is a rare complication of radiotherapy with complex neurological impairment. Patients present with neurological symptoms and signs such as migraine, hemianopsia, hemiplegia, aphasia and/or seizures—without recurrence of neoplastic disease. In this report, we describe SMART syndrome in two adult patients 4 and 14 years following brain irradiation, respectively.

P14.65 Survival in a consecutive series of 467 glioblastoma patients: impact of prognostic factors and recurrent treatment at two independent institutions

BACKGROUND

Glioblastoma (GBM) is an aggressive primary brain tumor with median overall survival (OS) of less than one year in unselected adult patients. There is no standard therapy at recurrence. We aimed to evaluate OS in a consecutive series of GBM patients from Norway’s two largest regional health authorities, compare the effect of physicians’ choice of antineoplastic treatment upon recurrence and identify prognostic and predictive factors.

MATERIAL AND METHODS

Clinicopathological data from n=467 patients with histologically confirmed GBM diagnosed and treated at Haukeland and Oslo university hospitals from January 2015 to December 2017 was retrospectively collected. Data included tumor location, methylation status of the methylguanine-DNA methyltransferase (MGMT) promoter and mutation of the isocitrate dehydrogenase (IDH) genes, patient age and sex, extent of tumor resection at primary diagnosis, and treatment at first, second and third tumor recurrences. Cox-proportional hazards regression with pairwise analyses adjusted for multiple testing with Scheffé’s post-hoc test were used to adjust effect of multiple risk factors on mortality.

RESULTS

Median OS was 12.1 months and 21.4 % and 6.8 % of patients were alive at 2 and 5 years, respectively. Treatment at recurrence varied between institutions but did not impact OS (p=0.201). Median time to progression was 8.2 months. Age, MGMT promoter methylation, tumor location and extent of tumor resection were all independent prognostic factors for OS. Patients receiving radiotherapy to 60 Gray with concomitant and adjuvant temozolomide at primary diagnosis had best outcome with median OS of 16.1 months and 9.3% were alive at 5 years. At first recurrence patients eligible for gammaknife/stereotactic radiosurgery (GK/SRS) or surgery, alone or combined with chemotherapy, had superior survival compared to chemotherapy alone (p&lt;0.0001 and p=0.014, respectively). On Scheffé’s post-hoc analyses only GK/SRS was superior to chemotherapy (p=0.01). At second and third recurrence none of the antineoplastic strategies came across as superior or inferior to each other using Cox. On Scheffé’s post-hoc analyses chemotherapy alone and combined with bevacizumab were superior at second recurrence (p=0.008 and p=0.042, respectively) and chemotherapy combined with bevacizumab was superior at third recurrence (p=0.043), compared to no antineoplastic treatment. Our retrospective study is limited by small sample sizes and heterogeneous treatment groups, especially at second and third recurrences, as well as patient selection.

CONCLUSION

Recurrence treatment differed between the two institutions but there was no difference in OS. Our findings underline the lack of standard therapy upon GBM recurrence and the urgent need for novel therapeutic strategies.