Extracting Temporal Diffusion Biomarkers in Pediatric Brainstem Gliomas
We present a technique for extracting temporal diffusion MRI changes in tumor tissue called Serial functional Diffusion Mapping (SfDM). We are currently evaluating SfDM in biomarker extraction for pseudoprogression in pediatric brainstem tumors treated with immunotherapy.
Peptide-based immunotherapy works on the principle of introducing epitopes for antigens which are overly expressed in tumor cells, with the goal of triggering the patient's own immune response against the tumor, while ideally sparing healthy tissue. As the desired result is an inflammatory response, a challenge in clinical management arises in the early identification of tumor pseudoprogression. Pseudoprogression is defined as any symptomatic change in tumor volume not attributed to tumor progression, and is thought to be indicative of immunotherapy treatment response. However, pseudoprogression can only be diagnosed retrospectively. As clinical protocol calls for a halt in the treatment with any observed progression, it creates the problem of potentially stopping the therapy at a point when it is most effective. Therefore, the early detection of pseudoprogression is paramount to the development of an effective treatment plan.
Our goal is to incorporate SfDM into a predictive model capable of early detection of pseudoprogression for use in immunotherapy specific clinical decision support.