Pierce was diagnosed with Anaplastic Astrocytoma, a grade three tumor, on his right thalamus when he was 10 years old. The tumor size was too large for surgery. His treatment includes proton radiation, chemotherapy, multiple surgeries and a ketogenic (a high-fat, adequate-protein, low carbohydrate) diet. Four months after his diagnosis, the tumor was upgraded to a Glioblastoma, a grade four tumor. Glioblastomas are a rare and aggressive brain tumor with poor prognosis.