Dose-Volume relationships and prognostic factors for brain radiation necrosis in high-dose brain Irradiation beyond 60 Gy

• Applicant: Professor Dr. Maximilian Niyazi
• Subject Area: Nuclear Medicine, Radiotherapy, Radiobiology
• Term: from 2016 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317812742

Effective local control in brain tumors as well as in malignant neoplasias with brain infiltration or in close vicinity to the temporal lobe such as in nasopharyngeal cancer is hampered by normal tissue toxicity.There is a considerable increase in toxicity beyond 60 Gy according to QUANTEC.Lawrence and colleagues have described normal tissue toxicity according to the endpoint radiation necrosis without NTCP modelling. Their attempt was quite straightforward only considering the maximum dose of their respective DVH, transferring this into a BED value and plotting BED versus the rate of radiation necrosis.This method contains the disadvantage not considering the whole texture of the DVH which can be done by employing EUDs; according to the general NTCP model, a curve is modelled based on unknown EUD parameters which will be fitted by maximum likelihood methods - this will enable to derive the volumetric influence of high-dose volumes on the development of radiation necrosis (as, e. g. radiosurgery can deliver far higher doses to the brain without causing significant damage which can be taken as further argument for a volume effect).In reality, there might be much more parameters influencing the development of brain necrosis (stratification will be done by symptoms) such as the size of the irradiated volume, concomitant systemic therapy, localization of the tumor and many more factors; the influence of these factors besides the dose-volumetric association will be assessed by multivariate logistic regression analysis.Within this research project, it is consecutively planned to retrospectively identify such patients, to evaluate their proton plans and to develop a NTCP model on brain radiation necrosis.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Dr. Helen Alice Shih