Case report: Resolution of malignant canine mast cell tumor using ketogenic metabolic therapy alone

Abstract

Background: Mast cell tumors (MCT) are common neoplasms in dogs and are similar to most other malignant cancers in requiring glucose for growth, regardless of histological grade. Ketogenic metabolic therapy (KMT) is emerging as a non-toxic nutritional intervention for cancer management in animals and humans alike. We report the case of a 7 years-old Pit Bull terrier that presented in 2011 with a cutaneous mast cell tumor under the right nostril.

Methods: The patient's parent refused standard of care (SOC) and steroid medication after initial tumor diagnosis due to the unacceptable adverse effects of these treatments. Following tumor diagnosis, the patient's diet was switched from Ol'Roy dog food to raw vegetables with cooked fish. The tumor continued to grow on this diet until July, 2013 when the diet was switched to a carbohydrate free, raw calorie restricted ketogenic diet consisting mostly of chicken and oils. A dog food calculator was used to reduce calories to 60% (40% calorie restriction) of that consumed on the original diet. A total of 444 kilocalories were given twice/day at 12 h intervals with one medium-sized raw radish given as a treat between each meal.

Results: The tumor grew to about 3-4 cm and invaded surrounding tissues while the patient was on the raw vegetable, cooked fish diet. The tumor gradually disappeared over a period of several months when the patient was switched to the carbohydrate free calorie restricted ketogenic diet. The patient lost 2.5 kg during the course of the calorie restriction and maintained an attentive and active behavior. The patient passed away without pain on June 4, 2019 (age 15 years) from failure to thrive due to an enlarged heart with no evidence of mast cell tumor recurrence.

Conclusion: This is the first report of a malignant cutaneous mast cell tumor in a dog treated with KMT alone. The resolution of the tumor in this canine patient could have been due to the diet-induced energy stress and the restriction of glucose-driven aerobic fermentation that is essential for the growth of most malignant tumors. Further studies are needed to determine if this non-toxic dietary therapeutic strategy could be effective in managing other canine patients with malignant mast cell tumors.

Keywords: aerobic fermentation; calorie restriction; canine; glucose; ketogenic diet; nutrition.

FIGURE 1

A large cutaneous mast cell tumors (MCT) (photographed on July 18, 2013) is seen under the right nostril and invasion to the nasal planum, consistent with malignancy (23). (A) The tumor gradually resolved over several months after the patient’s parent initiated the carbohydrate-free, calorie restricted ketogenic diet (B–D), as described in methods. The small bare patch on the lip below the tumor can serve as a reference point to assess the degree of the diet-linked tumor shrinkage. A facial image from October 2016 is also shown in the Supplementary material.

FIGURE 2

Timeline of clinical course with dates of dietary treatments.