Options for Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) should be considered a differential for any cutaneous lesion, particularly nonhealing scabbing lesions on the eyelids, nasal planum, or ears of light-colored cats. This study reported that SCC accounts for 15% of skin tumors and most malignant oral tumors in cats. The most common cause of cutaneous SCC is chronic exposure to ultraviolet (UV) light, particularly UVB radiation, and SCC is seen almost exclusively on the head. White cats or cats with white areas are at greatest risk. Lesions often appear as reddened, nonhealing scabby craters. Diagnosis is best achieved via punch or excisional biopsy of multiple abnormal sites. Treatment options for solar-induced SCC depend largely on the site affected and the lesion extent. Staging is based on invasion depth and lesion size. Staging the primary lesion is particularly important for nasal planum tumors as it directly impacts success. Surgical excision is the most successful treatment for lesions of the pinnae, eyelids, and invasive SCC of the nasal planum; cosmetic outcome is the major limitation. Cryosurgery is an option for superficial tumors, and orthovoltage, megavoltage, and proton beam irradiation have been used for nasal planum SCC. Beta radiation can be used successfully for superficial SCC lesions; major advantages are local normal tissue sparing and repeatability. Photodynamic therapy has also been used for superficial lesions of the nasal planum.

CommentaryFeline cutaneous SCC, a problematic disease presentation, can vary so widely that it is difficult to directly compare different treatment modalities and impossible to offer blanket statements about the best therapy. This is a fair summary of the disease, its workup, available treatments, and published results. The author made the wise decision to confine discussion to published therapies, although doing so can occasionally leave out some potential treatment options, such as strontium brachytherapy for bowenoid carcinoma.—Suzanne Shelly Waltman, DVM, DACVIM (Oncology)

SourceCutaneous squamous cell carcinoma in the cat: Current understanding and treatment approaches. Murphy S. J Feline Med Surg 15:401-407, 2013.