One of the most common types of skin cancer found in all animals is squamous cell carcinoma. This cancer develops on either the epidermis or the epithelium layers of the skin right at the root sheath of the hair follicle. In dogs there are actually two different types of squamous cell carcinoma found and each of the two is more common to specific breeds, indicating a genetic factor involved in the development of the cancer.
Cutaneous squamous cell carcinoma is most commonly seen in breeds such as the Basset Hound, Standard Poodle and the Bloodhound and usually only in older dogs of these breeds. The lesions start as small, irregular bumps often found on the head, between the pads of the feet, on the lower stomach and on the genital area of both males and females. These raised wart looking bumps are often ulcerated and very rough and irritated looking. In very short haired breeds such as the Beagles, Bull Terriers and even Dalmatians this condition can be noted along the back as well. It is believed that light skinned dogs that are exposed to a lot of direct sunlight and may even have sunburn problems are more likely to develop this type of squamous cell carcinoma.
The second type of squamous cell carcinoma is subungal squamous cell carcinoma. This condition is seen on dark coated dogs with females having a slightly higher rate of the condition. The breeds most commonly affected with this type of squamous cell carcinoma include the Kerry Blue Terrier, Giant and Standard Schnauzers, Standard Poodles, Briards and Gordon Setters. These cancerous growths tend to develop on the legs and feet of the affected dogs with often both hind and front legs developing the lesions. These tumors are highly malignant in most cases and will soon attack the bones of the legs and the feet and may first be detected when the dog becomes lame.
The more differentiated or easy to see and contained the tumor is the greater the likelihood that it can be successfully removed without a reoccurrence. The greater the spread of the tumor and the more locations that tumors are present on the body the less likely that treatment will be successful. In most cases the recommended treatment is complete removal of all affected tissue plus a margin of healthy tissue to ensure full removal. In cases where bone has been compromised, removal of the solid bone section is recommended if at all possible. In cases where the pads of the feet are involved partial amputation may be needed to eliminate all infected tissue.
Cryosurgery or freezing the tissue can be successful with some types of squamous cell carcinoma although not all vets are trained in this procedure. Chemotherapy and some drug therapies are also possibilities for treatment, again depending on the location, size and spread of the squamous cell carcinoma. Limiting exposure to the sun and carefully monitoring the dog after treatment for any signs of reoccurrence will be essential in controlling any further progression of the condition.