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Proton-Based Radiation Therapy for Skull Base Chondrosarcomas in Children and Adolescents: 40-Year Experience From
Myrsini Ioakeim-Ioannidou1, Saveli Goldberg2, Tobias Urell2
1Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; Department of Radiotherapy, School of Medicine, University of Crete, Heraklion, Greece.
Insights
Proton-based radiation therapy (PBRT) offers excellent outcomes for young patients with skull base chondrosarcoma (CHS), demonstrating high survival and local control rates with minimal toxicity in this largest reported cohort.
Area of Science:
- Oncology
- Radiation Oncology
- Pediatric Oncology
Background:
- Skull base chondrosarcoma (CHS) is rare, particularly in pediatric and young adult populations.
- Limited literature exists on the treatment and outcomes for this specific demographic.
Purpose of the Study:
- To report treatment outcomes for patients aged ≤22 years with skull base chondrosarcoma (CHS) treated with proton-based radiation therapy (PBRT).
- To evaluate the efficacy and safety of PBRT in this patient cohort.
Main Methods:
- Retrospective review of patients treated with PBRT between 1981 and 2023.
- Analysis of primary endpoints including overall survival (OS), chondrosarcoma-specific survival (CSS), progression-free survival (PFS), local, and distal control.
- Assessment of patient demographics, tumor histology, surgical interventions, and radiation dose.
Main Results:
- Eighty-four patients (median age 19 years) with conventional (94%) and mesenchymal (6%) CHS were analyzed.
- Excellent 10-year survival rates: OS 93.3%, CSS 94.7%, PFS 88%. Twenty-year rates for conventional CHS were also high.
- Mesenchymal histology and pre-radiation tumor progression were associated with worse outcomes. Late grade ≥3 toxicity occurred in 9.9% of patients.
Conclusions:
- This study represents the largest cohort of pediatric and young adult skull base chondrosarcoma treated with PBRT.
- High-dose PBRT following surgical resection provides excellent disease control and favorable survival with manageable toxicity.
- PBRT is an effective treatment modality for skull base chondrosarcoma in young patients.
Purpose:
The literature on skull base chondrosarcoma (CHS) is scarce. We report outcomes for pediatric and young patients ≤22 years with base of skull CHSs treated with proton-based radiation therapy (PBRT).
Methods And Materials:
We retrospectively reviewed all patients treated with PBRT between 1981 and 2023. Primary endpoints were overall survival (OS), chondrosarcoma-specific survival (CSS), progression-free survival (PFS), local control, and distal control.
Results:
Eighty-four patients were identified. Median age at diagnosis was 19 years (range, 6-22). Most patients (n = 79, 94%) had conventional CHS, whereas 5 (6%) had mesenchymal CHS. Nine patients (11%) underwent gross total resection, 64 (76%) subtotal resection, and 11 patients (13%) underwent biopsy. Twenty-four (29%) patients progressed before radiation therapy. The median prescription dose was 70 Gy (relative biological equivalent) (range, 50-79.7). At a median follow-up of 18.0 years (IQR, 9.2-26.2) from diagnosis, 11 patients recurred (7 local, 4 distant). Six patients died of disease. Five patients died of other causes. Ten-year OS, CSS, and PFS rates for all patients were 93.3%, 94.7%, and 88%, respectively. Twenty-year OS, CSS, and PFS rates for conventional CHS (n = 79) were 93.1%, 97.1%, and 89.2%, respectively. Mesenchymal histology was significantly associated with worse OS and PFS. Preradiation therapy tumor progression portended worse OS and CSS. Eight patients (9.9 %) experienced a late toxicity grade 3 or greater.
Conclusions:
This is the largest cohort of pediatric base of skull CHSs in literature to date. High-dose PBRT after surgical resection achieves excellent disease control with minimal toxicity.
