Protons vs Photons for Brain and Skull Base Tumors
The physical characteristics of proton therapy result in steeper dose gradients and superior dose conformality compared to photon therapy. These properties render proton therapy ideal for skull base tumors requiring dose escalation for optimal tumor control, and may also be beneficial for brain tumors as a means of mitigating radiation-related adverse effects. This review summarizes the literature regarding the role of proton therapy compared to photon therapy in the treatment of adult brain and skull base tumors.
CONCLUSION: We derived NTCP models to predict G2-RIA after PT, providing a comprehensive modelling framework for acute, late and permanent occurrences that, once externally validated, could be exploited for individualized scalp sparing treatment planning strategies in brain tumor patients. PMID: 31805517 [PubMed - as supplied by publisher]
High-dose fractionated proton therapy is used to manage patients with skull base tumors such as clival chordomas or chondrosarcomas [8,14]. Proton therapy is also used in the treatment of patients with lower grade gliomas , meningiomas, and subsets of head and neck cancer patients with particular dosimetric benefit, such as those with tumors of the paranasal sinuses . Clinical outcomes support the utility of proton therapy in the disease control of these tumors but little is known on potential late side effects of brain radiation necrosis.
This study recruited two centers with expertise in treating pediatric brain tumors with robotic radiation delivery system photon therapy and proton therapy, respectively, to study the plan quality and the dose deposition characteristics of robotic radiation delivery system photon and intensity modulated proton therapy (IMPT) plans.Methods and MaterialsA total of 18 patients clinically treated with robotic radiation delivery system were planned with intensity-modulated-proton-therapy (IMPT). Cases were planned per the standard of care of each institution but, respected the same planning objectives. The comparison was perfor...
Conclusions: PT reduced the volumes of normal tissues exposed to radiation, particularly low-to-intermediate dose levels, and this was reflected in lower NTCP. Of the included endpoints, substantial reductions in population medians were seen from the delivered PT plans for auditory complications, xerostomia, and risk of secondary cancers of the brain and salivary glands. PMID: 31364899 [PubMed - as supplied by publisher]
Our institution utilizes both biologic and standard dose models in spot scanning proton treatment planning. This analysis examines the rates of post-treatment radiologic change as detected on post-treatment MRI scans, and toxicities for pediatric brain tumor patients treated during the first year of our institution ’s experience. Our novel biologic dose model was found to demonstrate greater volumetric overlap with the post-treatment radiologic changes, than the standard dose model.
Abstract ADVANCES IN KNOWLEDGE: This review details the indication of brain tumors for proton therapy and give a list of the open prospective trials for these challenging tumors. PMID: 31067074 [PubMed - as supplied by publisher]
(European Society for Radiotherapy and Oncology (ESTRO)) A comparison of three types of radiotherapy for children's brain tumors suggests that a type of proton therapy called pencil beam scanning offers the best hope of preserving cognitive functions.
CONCLUSIONSThis study provides an insightful understanding of dosimetric quality from both photon and proton treatment across the most advanced stereotactic radiotherapy platforms. PMID: 30901747 [PubMed - as supplied by publisher]
Our cohort of 174 pediatric patients with low-grade glioma demonstrate progression-free survival and overall survival rates of 84% and 92%, respectively, following proton therapy. These survival rates are similar to contemporary photon cohorts. Data from this prospective study inform radiation technique and overall patient management for the most common pediatric brain tumor.
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