Could predictive models, based off statistical analysis of previous patients’ treatment plans, change the way radiation therapy is delivered to patients whose cancer has spread to their brain, and lessen the side effects of the treatment as a result?
PA Hospital radiation therapist Erin Johns is aiming to prove it can, thanks to the supporters of the PA Research Foundation. Thanks to their support and funding, she is getting to put her theory into practice through a new research project and she couldn’t be more determined or thrilled.
Radiation therapy is a treatment option for many cancer patients but unfortunately it can affect healthy cells whilst treating and eliminating cancerous tissue. Erin’s project aims to determine the optimum amount of radiation, healthy brain tissue receives whilst also eradicating the cancerous cells in single brain metastasis for either a solid tumour or residual area of the brain after surgery.
“I've created three models and an accompanying framework that predicts what the smallest amount of low dose wash of radiation should be delivered to healthy brain tissue is whilst still achieving the treatment goals,” Erin said.
“We obviously need to treat patients that have a metastasis in the brain with radiation so that hopefully their cancer doesn’t return to that area, but we want to spare as much of the healthy brain as possible.
“I've created these models and a clinical framework to estimate what this low dose should be, depending on the size of the tumour, what part of the brain it is in and by looking at other significant variables that influence low dose wash. In particular, both patient and technical factors related to designing and delivering radiation therapy for brain metastases.
“We need to have the dose that is prescribed by the radiation oncologist to the tumour to ensure the cancer is treated but there's always going to be a little bit of extra that ends up in the normal brain tissue, it's unavoidable but I’m trying to reduce that amount as much as we can.
“There's just no data out there to say if your tumour is this big and, in this location (just to name a few considerations) how much low dose wash is acceptable for that patient’s specific situation. Because of this, we don't know when to stop trying to further improve the plan which can be very time consuming."
“What I'm trying to do is perfect a few models that can actually give you the most optimal estimate of what that number should be to minimize the amount of healthy tissue that receives radiation.”
Erin hopes that her project will result in better health outcomes for every patient who undergoes single brain metastases radiation therapy treatment at the PA, by reducing the side effects that result from healthy brain tissue receiving radiation.
“We want to try and reduce radiation dose as much as possible to areas of healthy tissue that don’t need it. There’s always some associated toxicity caused by radiation and it may cause some cognitive decline depending on where it is in the brain. Things like your short term memory, the ability to just think of a word, or recall someone's last sentence are good examples,” she said.
This study will use data from a new cohort of patients who have previously had treatment to determine the efficacy of the models and framework and based on the outcome. If all goes well, this will be implemented as the ‘gold standard’ going forward and she hopes to assist other radiation oncology departments too.
Additionally, another positive from her work will be a reduction in the time needed by radiation oncologists and therapists to generate a patient’s radiation therapy treatment plan which is used to deliver a patient’s treatment. Erin says “By having these models, we'll also be able to reduce the time it takes to plan each patient’s treatment. It should reduce that planning time and should be able to reduce the number of plans that are currently generated before the amount of low dose of radiation can be determined because now, we'll have this ideal number that was predicted each time to be effective.”
“I started this research a few years ago, when the doctor I work directly with on this research, Associate Professor Mark Pinkham, wanted me to look at these plans as we were seeing some variability in the way these plans were being created. Not long after I started this research did I enroll in my Masters of Philosophy and not long after did I transfer into a PhD. I guess it was something that's really interesting to me, intracranial lesions and patient quality of life and trying to improve that wherever we can.
“It’s my first research project so it means a lot to me. I’m absolutely stoked I get to do this thanks to the Foundation and its supporters.”
Erin Johns is extremely thankful to those who choose the PA Research Foundation as their place to give, for giving her the opportunity to prove her concept, complete her PhD and help patients.
