Tumors On Dogs’ Paws

Most dogs love going for walks. Running and jumping are playtime. Such activities are important both as exercise and for a dog’s mental stimulation, so it merits a closer look if one of your dog’s paws appears to be bothering him or her. Infections or foreign bodies can hinder a dog’s mobility, but tumors can grow on dogs’ paws, too — including on or in between the toes. This occurs mostly with older dogs (starting at about age 9 or 10) and can trigger incessant licking and/or result in them favoring the affected paw.

There are several types of digital tumors in dogs, and thus there are also several different options to treat them. The primary objective of treatment is removal or local control of the tumor to enhance the dog’s quality of life and attempt to significantly extend your time together. 

Types Of Canine Digital Tumors

Cancer that originates in a dog’s toe can metastasize (spread). For example, cancer can metastasize to the draining lymph nodes — typically the prescapular or axillary lymph nodes up front, or the popliteal or inguinal lymph nodes if the cancer originates from the hindlimb toes. It can also spread to the lungs. Here’s a look at the five most common types of tumors on dogs’ paws:

• Melanoma: Digital melanoma in dogs can also spread up the leg, to the lungs and/or to the liver.
• Squamous cell carcinoma: Digital squamous cell carcinoma in dogs can spread to the lymph nodes and lungs.
• Fibrosarcoma/Nerve Sheath Tumor/Other types of soft tissue sarcomas: This type of cancer is another that can spread to the lymph nodes and lungs.
• Mast cell tumor: These tumors can spread to other areas of the skin, as well as to the lymph nodes, the lungs, the liver and the spleen and the bone marrow.
• Plasma cell tumor: These tumors also can spread to the lymph nodes and lungs. 

Clinical Signs To Look For 

Depending on the size and location, a lump on a dog’s paw can obviously impede his or her ability to walk or run normally. However, if your dog is lame or limping, other afflictions could be the cause as well. Often limping in a dog will result from a sprain or tear in the tendon of a canine’s leg. Dogs will limp if there is an issue with their toe. Your dog might have an infection, inflammation or an allergy, or he or she may have a foreign object embedded in a paw pad if he or she stepped on something. If your dog displays any of these signs, examine his or her paw and have a veterinarian take a closer look if there’s reason to suspect a tumor. Some things to look for:

• A mass on a toe
• A toenail problem — a nail might seem loose, growing in a different direction or seem malformed.
• Your dog holds his or her paw up or is not bearing as much weight on that leg
• Incessant licking of the paw — many dogs lick their paws, but extraordinarily incessant licking indicates an issue
• Lethargy
• A bloody footprint — you might think it’s due to a cut but it’s not, as a mass can bleed

Workup & Diagnosis

Before performing specific tests to detect a tumor or determine whether a growth is cancerous, a veterinarian would examine the dog’s leg and paw. If a tumor is suspected or obvious, the workup could include some combination of the following:

Foot X-rays: X-rays can determine if a tumor or even infection has eaten away an area of the bone. X-rays can also help reveal if a foreign body is imbedded in the paw.

Chest X-rays: These may be ordered because many types of cancer spread to the lungs.

Bloodwork and urinalysis: A blood chemistry profile and a CBC can reveal a wealth of information about the patient’s overall physical status as well as organ function.

Abdominal ultrasound: An ultrasound could be performed to rule out the potential spread of cancer to vital organs.

Aspiration: A needle is used to withdraw fluid or tissue, which is then sent to a lab to determine the makeup of a mass (infection, cancer). A veterinarian also may aspirate the draining lymph nodes to determine potential spread.

Treatment Options

Because toe cancer in dogs can be any of several different types, treatments can vary — even more so if the cancer has spread. 

Surgery

There are two surgical approaches with cancer in general. Debulking a tumor is a procedure to reduce its size in hopes that chemotherapy or radiation will be more effective, but the tumor typically comes back. That’s why surgical removal of the entire toe is often recommended if that’s where the mass is located. When the toe is removed, the goal is to get clean, wide margins — meaning the areas at the edges of the removed tissue have no cancer cells, an indication that the cancerous tissue has been completely removed.

Conventionally Fractionated Radiation Therapy (CFRT)

If surgery is not an option or if clean margins are not obtained through surgery but the cancer has not spread, this conventional type of radiation can be used to control or slow the growth of the remaining cancerous tissue. However, this is a prolonged treatment course, usually consisting of 16 to 21 treatments.

Stereotactic Radiation

In stark contrast to CFRT, Stereotactic Radiation uses high doses of radiation and typically requires just 1-3 sessions. This newer treatment option delivers radiation with sub-millimeter precision, aiming to damage cancerous tissue that was not surgically removed, while at the same time preventing or minimizing damage to the surrounding healthy tissue. The difference in number of treatments is significant because anesthesia is required for each radiation treatment. The team at PetCure Oncology has extensive experience with Stereotactic Radiation.

Chemotherapy

If the cancer on a dog’s paw is melanoma, then surgery or radiation is followed with an intradermal melanoma vaccine regimen. The vaccine stimulates the dog’s body to make antibodies against melanoma. Since it takes four to five months to mount an adequate immune response, it is important to have good local control of the primary tumor site.  Vaccines are administered once every two weeks for four treatments, then once every six months thereafter.

Chemotherapy may also be part of the treatment plan if cancer has spread to the lymph nodes or if the primary mass is terribly aggressive. Both the toe with the tumor and any affected lymph node(s) may be surgically removed or treated with radiation. Chemotherapy would follow. There are intravenous and oral options.

Other Drugs

In the case of mast cell tumors, a corticosteroid called prednisone can slow down growth for a few months. Antibiotics and/or pain medication also may be prescribed, depending on the patient’s clinical signs.

Prognosis

The prognosis for a dog with a digital tumor depends largely on the type of tumor.

• With squamous cell carcinoma, if good local control is achieved through treatment, it might be a year before the cancer comes back or spreads.
• If the tumor is fibrosarcoma/soft tissue sarcoma or a plasma cell tumor, there’s a chance of the cancer being cured if clean margins are obtained or if radiation is successful.
• If the tumor is melanoma, it might be anywhere from six months to a few years after treatment before the cancer becomes an issue again.

As the cancer progresses, a tumor on a dog’s paw may get bigger and messy — it may ooze or bleed and become irritated. Because cancer competes for nutrients, a stricken dog eventually will lose weight even if he or she is eating normally. Eventually, he or she won’t feel well and the pet parent will have decisions to make based on the dog’s quality of life.

Find A PetCure Oncology Location Near You

A lump on a dog’s paw can be treated even if it’s a cancerous tumor. PetCure Oncology provides innovative treatments for many types of cancer. We care about your dog’s health. In fact, providing a good quality of life and extending your time with your dog is our mission. You will know that based on the professionalism and support that we demonstrate at all times.

For more information about PetCure Oncology and our treatment options, find a location near you today.