Abstract
PurposePurpose of this study was to investigate overall survival in recurrent glioblastoma treated with either carbon ion reirradiation or photon reirradiation.Materials and methodsIn this retrospective study we evaluated 78 consecutive patients with recurrent IDH (Isocitrate dehydrogenase)-wildtype glioblastoma (38 patients carbon ion re-radiotherapy, 40 patients photon re-radiotherapy) treated with either carbon ion reirradiation or stereotactic photon reirradiation. 45 Gy (RBE; 15 fractions) carbon ion reirradiation (CIRT) or 39 Gy (13 fractions) photon reirradiation (FSRT) was administered, respectively. Overall survival was investigated with respect to histological, clinical, and epidemiological features. Kaplan–Meier and multivariate Cox statistics were calculated. A propensity score-matched analysis of the FSRT and CIRT groups using variables from a validated prognosis score was carried out.ResultsThe type of reirradiation (CIRT vs. FSRT) significantly influenced overall survival—8.0 months vs. 6.5 months (univariate: p = 0.046)—and remained an independent prognostic factor in multivariate analysis (p = 0.017). Propensity score-adjusted analysis with CIRT versus FSRT as the dependent variable yielded a significant overall survival advantage for the CIRT group (median OS 8.9 versus 7.2 months, p = 0.041, 1‑year survival 29 versus 10%). Adverse events (AE) were evaluated for both subgroups. For the FSRT group no toxicity ≥ grade 4 occurred. For the CIRT subgroup no grade 5 AE occurred, but 1 patient developed a grade 4 radionecrosis. We encountered 4 grade 3 toxicities. One patient developed a zoster at the trunk, 2 progressed in their paresis, and 1 featured progressive dysesthesia.ConclusionIn conclusion, carbon ion treatment is a safe and feasible treatment option for recurrent glioblastoma. Due to the retrospective nature of the study and two different dose levels for CIRT or FSRT, the improved outcome in CIRT reirradiation might be an effect of higher biological impact from carbon ions or a simple dose-escalation effect. This hypothesis needs prospective testing in larger patient cohorts. A prospective phase III randomized trial is in preparation at our center.
Highlights
Patients and methodsMalignant glioblastoma is the most frequent tumor of the central nervous system (CNS), with an incidence of around 4700 per year in total or 5–8 per 100,000 in Germany [1]
Due to the retrospective nature of the study and two different dose levels for carbon ion reirradiation (CIRT) or fractionated stereotactic radiotherapy with photons (FSRT), the improved outcome in CIRT reirradiation might be an effect of higher biological impact from carbon ions or a simple dose-escalation effect
In this study we investigated the impact of CIRT reirradiation in the treatment of recurrent glioblastoma
Summary
Patients and methodsMalignant glioblastoma is the most frequent tumor of the central nervous system (CNS), with an incidence of around 4700 per year in total or 5–8 per 100,000 in Germany [1]. Current standard of care in newly diagnosed glioblastoma consists of surgery, fractionated chemoradiation with temozolomide up to 60 Gy total dose, and maintenance temozolomide for 6 months [2, 3]. Tumor control and overall survival by chemotherapy is limited: so far, no chemotherapeutic regimen has shown substantial improvement [4, 5]. Reirradiation (re-RT) for recurrent glioblastoma has been available for about 20 years [7, 9, 10, 12] and is commonly offered as fractionated stereotactic radiotherapy with photons (FSRT). The outcome in recurrent glioblastoma is bleak, with overall survival rates of only months following treatment of first relapse [7, 9, 10, 12]
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