Even though a large amount of normal-looking tissue was taken from around the mass, this type of tumour is very aggressive and can spread elsewhere in the body. Between 30 to 40% of high-grade mast cell tumours will recur even if the tissue margins are free of tumour cells. Survival time for high-grade tumours is approximately 180 to 320 days with only 24% of animals diagnosed still alive at 12 months. This compares to low-grade mast cell tumours where 95% are still alive at 12 months and very few regrow.
Due to being diagnosed with such an aggressive form of this cancer, Louis’s owners elected for chemotherapy to try and kill off any remaining cancer cells that may still be present in his body. This consists of him receiving IV chemotherapy once a week for 4 weeks then another 4 treatments 2 weeks apart. So far Louis has had the first 4 treatments and suffered no side effects at all from the chemotherapy. The main side effects we were concerned about are his white blood cell numbers dropping too low, or Louis feeling nauseous or vomiting but so far none of this has happened and he continues to be his happy old self.