Dear OncoLink "Ask the Experts,"
Our 5 yr old male Maine Coon was first diagnosed with an eosinophilic granuloma, which was removed. It grew back. We began treatment with Strontium and Leukeran. The growth was responding until the Leukeran was reduced. Then it began to grow and an oro-nasal fistula was discovered. The growth was re-diagnosed as a fibrosarcoma in his nasal cavity and he began 17-days of radiation treatments.
Last week the tumor was seen to be growing again. Our veterinary oncologist isn't sure where to go from here. She suggests, perhaps, photodynamic therapy. She says nasal surgery doesn't usually work well in cats and radiation doesn't seem to help.
Can you offer any direction?
Lili Duda, VMD, Editor of the OncoLink Veterinary Oncology Section, responds:
Feline maxillary/nasal fibrosarcomas are extremely locally invasive tumors that are unlikely to metastasize elsewhere in the body. For tumors that are small enough to remove surgically, the best approach is to combine surgery with either pre- or post-operative radiation therapy. Unfortunately, most of these tumors are much too large to be amenable to surgical resection by the time they are discovered in a cat. CT or MRI scan (or skull radiographs if the other options are not available) can be very useful in determining the extent of the tumor, because often the visible part of the tumor is only the "tip of the iceberg". Radiation therapy by itself might be useful in palliating a large fibrosarcoma, but is very unlikely to provide long-term control of these tumors. Re-irradiation is generally not recommended for tumors that recur soon after the initial radiation course. Similarly, chemotherapy might provide temporary palliation of rapidly growing tumors. Antibiotics and anti-inflammatories are often used to control the secondary inflammation and infection often associated with tumors in this location.
If you or your veterinarian have not already done so, please consult a qualified veterinary oncologist to further explain the treatment options for your pet.