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154 Nonmelanoma Skin Cancers 1357

with receptor tyrosine kinase inhibitors, to inhibit nor­ setting, and results are generally anecdotal and not
VetBooks.ir mal stromal cells that support neoplastic growth. Little well documented. Cisplatin, carboplatin, bleomycin,
actinomycin D, and mitoxantrone have all been used
information is currently available about the use of daily,
low‐dose combination metronomic chemotherapy in
literature. Local drug delivery enhanced by electro­
canine and feline skin or ear canal tumors. sporadically, with modest response rates noted in the
Papilloma lesions may be addressed through the crea­ chemotherapy may increase the local efficacy of these
tion of an autologous vaccine. This approach is best used cytotoxic agents.
in dogs with multicentric papillomas, as is sometimes
seen in dogs that have been heavily immunosuppressed
in the transplant or autoimmune disease setting, or in Prognosis
dogs with immunosuppression from T‐zone lymphoma.
In this approach, 1–3 g of papilloma tissue are harvested The prognosis for patients with localized tumors of the
from the dog and macerated in a tissue grinder or mortar skin, adnexal structures, or ear canals is generally highly
and pestle along with 10 mL of sterile 0.9% saline. To this favorable. Many lesions are benign and early detection is
mixture is added 1 mL of neutral buffered formalin, possible because of the superficial location of the tumors,
which inactivates live virus as well as altering the struc­ and ear canal tumors are frequently localized to within
ture of viral oncoproteins to facilitate immune recogni­ the cartilaginous structures of the ear canal, which facili­
tion. The mixture is refrigerated for three days, and then tates complete resection. Thus, most dogs and cats
sieved through sterile cheesecloth or a large‐gauge filter affected by skin or ear canal tumors are cured by surgical
to remove residual particulate material. The resultant excision alone. Exceptions are noted in cases of malig­
autologous vaccine can be stored in the refrigerator in nant skin neoplasia, particularly when metastasis to
1 mL sterile aliquots for future treatment. An immune nodes or distant sites is observed. Radiation therapy
adjuvant such as Immunocidin® (Corynebacterium can be helpful for large or nodally involved lesions,
parvum derivative), squalene, or BCG is added before as described earlier.
injection into the residual papilloma lesions. This treat­ The most common aggressive skin tumors discussed
ment can be repeated at weekly intervals until lesion here are squamous cell carcinomas, which have median
regression is noted. There is no literature regarding use survivals of 1–2 years with aggressive surgery and/or
of commercial papillomavirus‐preventive vaccines in the radiation therapy in both dogs and cats. The exception to
therapeutic setting. this observed survival rate is in the case of nasal planum
Systemic chemotherapy or local electrochemotherapy squamous cell carcinomas in dogs, which are both locally
has been attempted for aggressive or metastatic dermal aggressive and metastatic to regional nodes, and have a
carcinomas. Relatively few agents have been used in this poorer overall outcome despite aggressive therapy.

Further Reading

Gross TL, Ihrke PJ, Walder EJ, Affolter VK. Section Two: Munday JS, Kiupel M. Papillomavirus‐associated
Neoplasms and Other Tumors. In: Skin Diseases of the cutaneous neoplasia in mammals. Vet Pathol 2010;
Dog and Cat: Clinical and Histopathologic Diagnosis, 47(2): 254–64.
2nd edn. Ames, IA: Blackwell Science, 2005, pp. Vilar‐Saavedra P, Kitchell BE. Sunlight‐induced skin cancer
561–689. in companion animals. In: Baldi A, Pasquali P, Spugnini
Hauck ML. Tumors of the skin and subcutanous tissues. E, eds. Skin Cancer: A Practical Approach. New York:
In: Withrow SJ, Vail DM, Page R, eds. Withrow and Humana Press, Springer Science+Business Media, 2013,
MacEwen’s Small Animal Clinical Oncology, 5th edn. pp. 499–513.
St Louis, MO: Elsevier Saunders, 2012, pp. 305–20. Villamil JA, Henry CJ, Bryan JN, et al. Identification of the
Lascelles BD, Parry AT, Stidworthy MF, Dobson JM, White most common cutaneous neoplasms in dogs and
RA. Squamous cell carcinoma of the nasal planum in evaluation of breed and age distributions for selected
17 dogs. Vet Rec 2000; 147(17): 473–6. neoplasms. J Am Vet Med Assoc 2011; 239(7): 960–5.