Brachytherapy Effectiveness

Brachytherapy is a type of treatment administered to patients in order to treat cancer in various parts of the body. While there are many established protocols, most oncologists (when offered a series of feasible treatment plans) pick one based on experience/generic patient characteristics. There is currently no quantitative or standard way to compare two different treatment options for a given patient in a way that clearly identifies which is more effective than the other.

Work in this area is ongoing and promising, but as a starting point, I looked to find an initial way of comparing the effectiveness of different treatments.

Each treatment comprises of a dose of radiotherapy to the tumour and an unnecessary dose to each of the surrounding organs - there are limits to these doses: too low on the tumour and the treatment is not sufficiently effective; too high on other organs and the patient will have unnecessary toxic effects.

After some data analysis, I identified a homomorphic transformation that turned these values into n-dimensional vectors, whose magnitude allowed us to reason about its effectiveness. I found that if we take the treatment doses, and make each a component of a vector, except the value corresponding to the tumour dose - this we replace by 130 minus the initial value - then there is an inverse correlation between the magnitude of the resulting vector and the effectiveness of the treatment. I judged effectiveness by getting an experienced oncologist to rank the treatments. There is scope in the near future to make this much more precise.

This work was accepted and then presented as an abstract and poster at the European Society for Therapeutic Radiology and Oncology (ESTRO) 2024.