Several types of malignant tumors occur in canine feet, usually involving the toes. If your dog is diagnosed with paw cancer, your vet will likely refer you to a veterinary oncologist for treatment. Although your pet's prognosis depends on the type of tumor and whether it has spread, early detection and treatment offers the most hope.
Types of Paw Cancer
Melanoma and squamous cell carcinoma are the two most common types of canine foot cancer. The former usually causes the tumor to contain dark pigment, but that's not always the case. Squamous cell carcinoma most often appears in large breed dogs, especially those with dark hair, such as Labrador retrievers, Rottweilers, standard poodles and giant schnauzers. These tumors usually appear as small, reddish growths, enlarging over time. Mast cell tumors can also affect the feet. You might discover this tumor because your dog is chewing at his feet, as mast cell tumors tend to itch.
Signs of Paw Cancer
While any dog can develop paw cancer, it occurs most often in canines over the age of 10. If you feel a mass on your dog's foot, even if it doesn't appear to bother him, take him to the vet. Other signs of paw cancer include limping, swollen paws or toes and nail loss, as well as foot bleeding or ulceration. The initial swelling of a toe looks much like an infection, so your vet might prescribe antibiotics to combat it. Only when antibiotic therapy doesn't work does a vet usually conduct further testing and diagnose a tumor.
Diagnosing Foot Cancer
Your vet will biopsy the tumor to determine whether it is benign or malignant. If the tumor develops on a toe, she may need to amputate it to perform a biopsy -- which is also the traditional treatment. Before the biopsy, your vet will conduct other testing, including blood work and a urinalysis, to ensure your dog is healthy enough to undergo anesthesia and surgery. She'll also perform X-rays and ultrasounds to see if the tumor has metastasized beyond the foot to other organs.
Treatment and Prognosis
If the tumor occurs in the toe, surgical removal is the treatment of choice. If the cancer has not spread, this amputation can result in a cure. For most dogs, losing a toe doesn't markedly affect the ability to walk. The prognosis is usually better for squamous cell carcinomas than for melanomas. The latter have often metastasized by the time of diagnosis, so the dog may require post-surgical chemotherapy and radiation, along with a melanoma vaccination. Although the dog already has melanoma, the vaccine can improve long-term survival. On average, dogs survive about a year after treatment for a metastasized melanoma on the foot. If a mast cell tumor has spread, the dog may require chemotherapy and radiation. The affected dog may only survive a few months.