Dear OncoLink "Ask the Experts,"
Our 4 1/2 year old mixed breed female dog was recently diagnosed with a small intermediate grade mast cell tumor on her left eyelid. We understand that diagnosis of such a tumor in this location is quite rare. Some of the tumor was removed surgically (when it was presumed to be a cyst). Chest x-rays and abdominal ultrasound were normal. We are awaiting the results of lymph node aspiration.
After consulting three doctors in addition to our regular veterinarian, suggested treatments have included: steroid treatment alone; cryosurgery to remove more of the eyelid; radiation therapy alone; complete surgical removal of the eye to attain adequate margins; or complete surgical removal in conjunction with radiation therapy.
We are concerned with stopping the spread of cancer and giving her the best chance for long-term survival. However, the location of the tumor makes treatment difficult, as most recommended treatments will result in partial blindness. We would appreciate any direction you could give us.
Lili Duda, VMD, Editor of the OncoLink Veterinary Oncology Section, responds:
The eyelid is not an unusual location at allthese tumors can happen anywhere on the skin (I've seen quite a few on the head). This is a site where radiation therapy is frequently used, because it is a location where wide surgical excision can be difficult. Radiation therapy is a good treatment option for this location, because it can potentially maintain better cosmetic results and eyelid function than a more aggressive surgery. There is a chance of maintaining vision in the eye as well. A wide surgery (i.e., removal of the lid which would necessitate removing the eye) would also be adequate and would not require radiation (unless the biopsy showed evidence that residual tumor remained behind, which sounds very unlikely based on your description of the tumor). Prednisone as the sole therapy is only recommended when surgery or radiation are not treatment options.
Thank you for your question and interest. If you or your veterinarian have not already done so, please consult a qualified veterinary oncologist to further explore the treatment options for your pet.