Winston Ford, an 11-year-old male neutered Maltipoo, despite being non symptomatic, was found to be hypoglycemic after undergoing pre-anesthetic bloodwork. Winston was then seen by the Department of Internal Medicine at Veterinary Specialty & Emergency Center of Thousand Oaks. An ultrasound revealed a left pancreatic mass, however no evidence of metastasis was found in the abdomen or on thoracic radiographs.
Winston was then taken to surgery to have the pancreatic mass removed. During surgery, an enlarged pancreatic lymph node was discovered and removed. Liver nodules were also noted, so the liver was biopsied as well. Biopsy confirmed an insulinoma which had spread to the local lymph node and liver. Winston was referred to the Department of Oncology at VSEC Thousand Oaks for continued therapy.
Enrollment in FidoCureⓇ was recommended to Winston’s parents in order to slow down the progression of the disease. As tissue was not submitted, a Data-Based Report with information about the diagnosis and recommended therapies was generated. Based on these recommendations, Winston began FidoCure enabled targeted therapy.
Potential therapeutic approaches for Winston's diagnosis were ARID1A, SETD2, and mTOR. ARID1A encodes a member of the SWI/SNF family that has activities to regulate transcription of certain genes and plays a role in altering chromatin structure for various cellular functions.
SETD2 is a gene that encodes a lysine methyltransferase which has been described for tumor suppressor properties in human cancer literature. Mutations in SETD2 contribute to epigenetic regulation and interact with or modify the activity of histone deacetylases (HDAC).
mTOR is a downstream component of the PI3K cellular signaling pathway. The activity of mTOR has been connected to both human and canine cancer because of potentiating signals for neovascularization and cell growth. A number of studies have looked at mTOR expression in dogs including the potential benefits of therapies that target mTOR and other PI3K active proteins for inhibition.
Based on the FidoCure Data-Based Report, Winston began Vorinostat (30 mg/kg every other day) in July of 2020. At his recheck in August, his glucose was normal on bloodwork. In September, his glucose remained normal and he had gained weight. At his three month recheck in October, re-staging diagnostics showed no pulmonary metastasis or recurrence of his pancreatic disease. The liver nodules found during surgery were noted on ultrasound.
In April of 2022, re-staging diagnostics were performed. Thoracic radiographs showed no evidence of metastasis. An abdominal ultrasound showed recurrent disease in his pancreas and lymph node; his liver disease was found to be stable. His therapy was continued given he was doing so well and his rechecks were continued every three months. Diagnostics were repeated in October of 2021, and his pancreatic and liver disease was considered to be stable if not improved. Again, there was no evidence of pulmonary metastasis on radiographs.
At his visit in January of 2022, Winston was still doing well at home. His glucose was low, and there was mild abdominal disease progression. However, neither of these were considered enough to warrant a change in therapy. In early June of 2022, Winston was euthanized due to poor mobility and arthritis.
On a combined treatment plan of surgery and FidoCure enabled targeted therapy, Winston survived two years following his initial diagnosis of metastatic insulinoma.
Insulinoma is most commonly treated with surgery and supportive care for any secondary hypoglycemia. Reported survival times for metastatic insulinoma average about 6 months. A case report from JAAHA 2019 reported a 24 month survival time for a dog with metastatic insulinoma treated with Palladia (Toceranib) and Prednisone. To our knowledge, this is the first report of a metastatic insulinoma case treated with Vorinostat.
“Our experience has been fantastic and as our oncologist, Dr. Rodriguez, said during our check up, the medications have extended Winston’s life. The pharmacists are always pleasant when I call for refills and the process is really easy.”