Veterinary Society of
Surgical Oncology

General Considerations

  • SCC accounts for 5% of canine skin tumors and 15% of feline skin tumors
  • predisposition to unpigmented or lightly pigmented skin exposed to solar radiation
  • possible association with canine papillomavirus and abnormalities in tumor suppressor gene p53
  • firm and nodular masses which may be either proliferative or erosive and extend deeply into the dermis
  • sites: limbs, trunk, scrotum, and head and neck
  • SCC tends to develop in lightly pigmented skin on the flank and abdomen in white English Bull Terrier, Dalmatian, Beagle, and Whippet breeds
  • preneoplastic changes include erythema, actinic necrosis, solar elastosis, and carcinoma in situ
  • cutaneous SCC is locally invasive with a low metastatic potential
  • multiple lesions are common varying from carcinoma in situ to more infiltrative and nodular lesions
  • cutaneous SCC is usually well differentiated, but anaplastic SCC may metastasize to regional lymph node and lung

Treatment

  • methods: surgical resection, radiation therapy, local hyperthermia, cryotherapy, and chemotherapy
  • retinoids (i.e., isotretinoin and etretinate) inhibit cell growth and induce cellular differentiation
  • retinoids are potent modulators of squamous differentiation in normal and malignant keratinocytes
  • etretinate is only effective against preneoplastic lesions
  • combination of isotretinoin and local hyperthermia are effective against early lesions
  • intralesional chemotherapy with 5-fluorouracil, cisplatin, BCNU, or methotrexate
  • antineoplastic effect of these agents associated with an intense inflammatory reaction and gloves should be worn during application and should not be applied to cats with SCC (neurotoxicity)
  • systemic chemotherapy inconsistent with response rates low and short-lived: mitoxantrone, actinomycin D, doxorubicin and cyclophosphamide, bleomycin, and cisplatin

SQUAMOUS CELL CARCINOMA

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