Skin cancer in dogs: FAQ

What is skin cancer?

Skin cancer is the abnormal growth of cells in the skin. The cancerous cells multiply and grow, leading to a growth It's important to check your dog regularly for any lumps or abnormalities.

There are multiple types of skin cancer in dogs:

Melanoma

Malignant melanomas can grow fast and spread quickly to lymph nodes and other organs. They develop in the skin's pigment-producing cells. These areas are usually the mouth and nose, but it can also be found on skin with fur in rare cases.

In humans, exposure to UV light is the primary cause of the disease but the trigger is less clear in dogs. Genetics may play a part.

Benign melanomas can also occur, and are more common.

Squamous cell carcinoma

Squamous cell carcinoma may be caused by exposure to the sun. This type of cancer can often be mistaken as a minor scrape with red, irritated skin. But it can also appear as firm, raised or ulcerated plaques. Sometimes it can have a wart-like surface. 

Early treatment is vital as it can quickly spread into surrounding tissue. This can make surgery more challenging and, in some cases, not possible. It rarely spreads to other parts of the body until later stages of the disease.

Mast cell tumours

Mast cell tumours are the most common form of skin cancer found in dogs. The mast cells of the immune system multiply out of control and form a lump on the skin. It can grow very quickly and be found on most parts of the body. Genetics, inflammation and irritation have been suggested as causes for the disease. 

Bulldogs, Boston terriers, pugs, Staffordshire terriers and retrievers are more prone to developing mast cell tumours.

What does skin cancer look like on dogs?

Skin cancer can appear in many different forms. This can include:

• lesions
• scabs
• warty lumps
• bumps on the skin

These may be black, brown, grey, pink or red in colour. Look out for any unusual lumps and bumps on your dog and contact your vet if you find anything unusual.

Most lumps are benign (not harmful). But spotting it early will give your dog the best chance of recovery if it the growth is found to be cancerous.

What causes skin cancer in dogs?

Not all cases are linked to sun exposure. But dogs with light skin, a thin coat or a lack of fur are most at risk at developing squamous cell carcinoma, especially if they have suffered sunburn at any point. 

Research also shows that certain dog breeds may have a genetic predisposition to the disease.

What does sunburn look like on dogs?

Sunburn can appear as red skin or hair loss. The most common areas affected are the bridge of the nose, belly, inside legs, ear tips, skin around the lips and any other area where skin pigmentation is low.

How do I protect my dog from sunburn and sun-related skin cancer?

Preventing your dog from being in the sun at peak UV times (usually between 10am and 3pm) is the best way to protect them from sunburn. Keep them indoors or ensure there are plenty of shaded spots in the garden.

If this is not possible, use sunscreen to protect their skin. Look for a specially formulated canine sun cream as these will be the safest and most effective. Always follow the instructions on the label.

How is skin cancer diagnosed?

If your vet suspects skin cancer, they will often carry out a fine needle aspiration or biopsy so that the cells can be examined under a microscope. This can determine whether or not the lump is cancerous. 

If the sample cannot establish a diagnosis (sometimes they can’t as they are very small) the vet will discuss whether a surgical biopsy is right for your dog.

How is skin cancer treated?

Thankfully, most skin cancers can be treated and cured successfully, often with an operation to remove the lump. Radiation or chemotherapy may also be offered, but it may not be suitable for all dogs (especially elderly dogs). Speak to your vet about the treatment options for your dog.

What is the prognosis for skin cancer in dogs?

The prognosis will depend on the type of cancer and how advanced or aggressive it is. But in many cases the prognosis is very good for dogs. Most go on to make a full recovery and lead a normal lifespan without any further problems.