Foot or Toe Cancer in Dogs

One-third of all dogs get cancer, and it is fatal for half of those. In fact, cancer is the leading cause of death in older dogs (10 years and over). The most important thing about cancer is finding and treating it early. There are several different types of foot and toe cancer in dogs and each have unique signs, causes, diagnoses, and prognoses. For that reason, it is essential to be vigilant with your dog’s health and grooming so you can pick up on some of the subtle changes that can give you early warning of cancer, such as swelling, sores that will not heal, and deformed or missing toenails.

Foot or toe cancer (digital and soft tissue cancer), which can include squamous cell carcinoma, melanoma, osteosarcoma, mast cell tumor, and malignant soft tissue sarcoma is common in dogs. Each of these types of cancer has their own set of signs and treatment, but the main sign in all of these is a swelling or ulcer on the foot or toe. If the cancer is found before it metastasizes (spreads), it is possible that it might be completely contained by amputating the affected toe or foot.

Each type of foot or toe cancer has its own set of signs, which are:

Squamous Cell Carcinoma

• Swollen toe or foot
• Sore or ulceration on toe that will not heal
• Crusted lump on toe/foot
• Deformed toenail
• Pain in foot
• Limping
• Unable to walk

Melanoma

• Loose or missing toenail
• Swelling of foot or toe
• Sore that will not heal on toe/foot
• Foot pain
• Limping
• Inability to walk
• Loss of appetite
• Weight loss

Osteosarcoma

• Swelling
• Limping
• Pain in affected limb

Mast Cell Tumor

• Swollen toes/foot
• Pain in toes/foot
• Sores or ulcer on toes/foot
• Limping
• Deformed toe or toenail
• Nail loss

Malignant Soft Tissue Sarcoma

• Swelling of the toe/foot
• Pain in the affected area
• Large lump in foot/toe
• Limping
• Inability to walk
• Misshapen toe or toenail

 Types

Squamous cell carcinoma is a skin cancer that is usually easy to see and has an excellent chance of survival if found and treated early enough. Malignant melanoma is a fast-moving cancer made up of darkly pigmented skin cells most often in dogs with dark skin and fur, such as the Terrier and Doberman Pinscher. Osteosarcoma is a common bone tumor found most often in giant dog breeds, such as Great Danes older than seven years. Mast cell tumor is a change in malignancy of the cells that affect allergic reactions that affect Bulldogs and Boxers most often. Malignant soft tissue sarcoma is a connective tissue disorder usually right under the skin that is easily detected by owners when grooming or petting.

Squamous cell carcinoma

• Exposure to sunlight and UV light
• Dark coated dogs (Black Labrador, Poodle)
• Large dogs (i.e. Rottweiler, Black Labrador, Giant Schnauzer, and Standard Poodle)

Malignant melanoma

• Unlike people, it does not seem to be caused by the sun
• Dark skinned dogs with dark fur (i.e. Terrier, Doberman Pinscher)

Osteosarcoma

• Giant breeds (i.e. Great Dane, German Shepherd)
• Older dogs (over seven years old)

Mast cell tumor

• Boxer
• Bulldog

Malignant soft tissue sarcoma

• Unknown
• Large breeds (i.e. Doberman Pinscher, Rottweiler, Labrador)

The veterinarian will do a complete and thorough physical examination including body temperature, blood pressure, and heart rate. You should be prepared to give the veterinarian your dog’s complete medical history, when the signs started, and whether the signs have gotten worse. Any changes in diet, exercise, and personality should be noted as well. The veterinarian may also need to run some tests on your dog, such as:

• Complete blood count (CBC)
• Blood gas
• Blood chemistry panel
• Urinalysis
• Stool sample
• Fine needle aspiration of swelling or lump
• Biopsy
• Digital radiographs (x-rays) of affected area and possible areas of spread

If the veterinarian suspects the cancer may have spread he may need to do some more tests, such as an MRI, CT scan or ultrasound.

Squamous cell carcinoma and malignant melanoma can both be treated by immediate removal of the affected area. If the cancer has metastasized (spread) amputation of the toe, foot, or limb is necessary and depends on how much the cancer has spread. Osteosarcoma usually requires surgery to remove the affected toe, and possibly the foot as well. Mast cell tumors are graded low, intermediate, or high after removal, and may require more tissue or the entire limb being amputated. Chemotherapy is usually recommended if the grade of the tumor is intermediate or high. Malignant soft tissue sarcoma is graded between low, intermediate, and high. Low and intermediate are treated with surgery to remove the tumor as well as the tissue surrounding the area. Chemotherapy and radiation therapy may also be needed for both intermediate and high-grade.

The recovery chances for your dog depends on the type of cancer, grade of the tumor, and if it has spread. In many cases, if you have found the cancer early and were able to get treatment right away, chances of recovery is good. Unfortunately, some of these cancers are fast moving and recurring so the survival rate may only be about 10 to 12 months. Be sure to follow up with your veterinarian when you are supposed to and always let him know if there are any changes in your dog’s condition.