Proton radiation therapy in the management of prediatric base of skull tumors
Presenter: E. B. Hug
Affiliation: Loma Linda University
Treatment of pediatric skull base tumors is limited by the dose of radiation that can be delivered because of critical normal tissues in this region.Ê Becuase of the unique physical characteristics of proton beams, a much higher dose of radiation can be delivered with this therapy when compared to standard photons. This study reports the experience of treating tumors of the skull base with protons at Loma Linda University and MGH.Materials and Methods:
- 29 patients with pediatric skull base tumors were treated by a single physician at two institutions with combined proton/photon irradiation (MGH) or protons only (Loma Linda University).
- There were 20 malignant tumors with the most common histology being chordoma (50%)(these were classified as malignant because of their aggressive behavior).
- There were 9 benign tumors with the most common histology being Giant Cell Tumors (66%).
- 27/29 received postoperative therapy
- patients were treated with 1.8-2 Cobolt Gray Equivalent (CGE)/day, 5 days per week to a dose of 50.4-74 CGE depending on the histology.
- Median follow-up is 3 years
- 5/20 (25%) of the patients with a malignant tumor experienced a local recurrence, 3/20 had distant metastases, and 1/20 had a surgical access failure.Ê Overall survival was 75% at 3 yrs.
- For the benign lesions, only 1/9 experienced a local failure.
- 2/29 patients had a severe toxicity resulting in sensory or motor deficits.
- 8 patients required hormonal replacement therapy.
- No formal neuropsychologic testing was performed.
- High doses of radiation can be delivered with combined proton/photon irradiation or proton irradiation alone to base of skull tumors
- This may offer a chance at longer term survival for these patients
- Proton therapy is an important option for the treatment of patients with these tumors
- Proton therapy is a standard of care for the treatment of adult base of skull tumors to deliver higher doses while sparing normal tissues.
- Sparing normal tissues in the pediatric population has even greater importance due to the functional, structural, and cosmetic deficits that are even more likely to occur in children.
- This small report supports the use of this treatment in the pediatric population.
- It is important that future studies incorporate neuropsychological testing into the design so late toxicities can be fully understood.