A study presented at ESTRO 38 in Milan, Italy, showed that the type of radiotherapy called proton therapy (PBS) offers the best hope for maintaining cognitive functions in children with craniopharyngioma brain tumors.
PBS provides a very accurate dose of radiotherapy through a very narrow proton beam. In craniopharyngioma patients whose tumors are deeply located deep in the center of the brain, PBS can be used to deliver a relatively low dose of radiation to the temporal lobes and hippocampus.
Since these two areas of the brain are strongly associated with memory function, reducing their exposure may help maintain the patient's ability to induce treatment after treatment.
Three types of radiotherapy were evaluated during the study: Volumetric Modulated Arc Therapy (VMAT), Double Dispersion Proton Therapy (DSPT), and PBS. Their use has been studied by researchers such as Aarhus University Hospital, Denmark, in ten children diagnosed with craniopharyngioma.
VMAT is a type of intensity-modulated radiotherapy (IMRT) that allows the radiation dose to be formed into a tumor by modulating the radiation beam intensity. Both DSPT and PBS are types of proton therapy that are more targeted to the tumor more specifically while conserving surrounding tissues, using high-energy beams to treat tumors that can be targeted with greater accuracy than other forms of radiotherapy.
Researchers have used previous research on the impact of radiation on children's brains, including time lobes and hippocampus, to select 30 structures in the patient's brain to study.
They used CT and MRI scans to accurately locate structures in each of these children's brains, and then compare three treatment plans for each child to see which type is better for these 30 structures to prevent radiation. The dose to each structure was categorized as low, medium, or high.
They found that doses to the temporal lobe were lower in PBS than in VMAT and DSPT. Study data allowed them to predict that proton therapy, and in particular PBS treatment, would result in less impairment of child memory function when using radiotherapy to treat craniopharyngioma.
A PhD student at the University of Aarhus Laura Toussaint said: “We have looked at three types of radiotherapy that focus on the successful treatment of brain tumors. We have found that proton pencil beam therapy seems to be by far the best to avoid parts of the brain that are important in children's memory. The next step would be to confirm this finding with clinical research in patients.
“The use of proton therapy has been expanding rapidly over the last decade and is increasingly available to cancer patients, especially children. This also means that further research can be done. "