Skin Cancer in Dogs: A Guide To Dog Melanoma and More

Skin Cancer in Dogs

Skin Cancer in Dogs: A Guide To Dog Melanoma and More

For many people, dogs aren’t just a pet, they’re full members of the family. They celebrate our victories with us and console us after tragedies, even if they never really seem to understand what’s happening. Owning a dog has been shown to be good for your health, but the way they readily accept us is good for the soul.

When your dog gets sick, it can be devastating. One of the most common serious illnesses dogs face is some form of skin cancer. That’s kind of a downer, but luckily if you educate yourself about what to look for and your options, your dog may be by your side for years to come.

Key Takeaways

  • Tumors can have different appearances.
  • Early detection is vital.
  • Diagnosis requires testing by a veterinarian.
  • Standard treatments can include surgery, chemotherapy, and radiation therapy.
  • Some alternative and experimental treatments exist.
  • Your role may be to love and care for your pet as they go through treatment.
  • The prognosis and treatment options can depend on the type of tumor and health of the dog.

Types of Skin Cancer in Dogs

Skin cancer is one of the most common skin ailments our furry friends may face. Our pups face greater exposure to the sun, as well as environmental toxins generally. It’s thought one reason growths are common on a dog’s lower legs, paws, or nail bed, for example, is due to repeated contact with pesticides.

For many people, dogs aren't just a pet, they're full members of the family. They celebrate our victories with us and console us after tragedies, even if they never really seem to understand what's happening. Owning a dog has been shown to be good for your health, but the way they readily accept us is good for the soul. When your dog gets sick, it can be devastating. One of the most common serious illnesses dogs face is some form of skin cancer. That's kind of a downer, but luckily if you educate yourself about what to look for and your options, your dog may be by your side for years to come. Key Takeaways Tumors can have different appearances. Early detection is vital. Diagnosis requires testing by a veterinarian. Standard treatments can include surgery, chemotherapy, and radiation therapy. Some alternative and experimental treatments exist. Your role may be to love and care for your pet as they go through treatment. The prognosis and treatment options can depend on the type of tumor and health of the dog. Types of Skin Cancer in Dogs Skin cancer is one of the most common skin ailments our furry friends may face. Our pups face greater exposure to the sun, as well as environmental toxins generally. It's thought one reason growths are common on a dog's lower legs, paws, or nail bed, for example, is due to repeated contact with pesticides.
Mast cell tumor (skin cancer) is the most common type of cancer found in dogs

More than half the growths found on a dog’s skin are benign and won’t develop into a health problem. They can be dangerous enough, however, that they are generally worth getting checked.

Squamous Cell Carcinoma

Squamous cell carcinoma is a type of cancer typically associated with sun exposure, which can damage cells in a way that can cause tumors. This type of tumor and skin cancer typically occurs in areas where there is no or only light fur [1].

However, squamous cell carcinoma can occur in places that don’t normally get a lot of sun, so there may be other causes or factors involved. The papilloma virus is one suspected culprit.

Squamous cell carcinoma will most often appear as raised, firm lumps or bumps on the dog’s skin.

Squamous cell carcinoma is actually pretty rare in dogs. Breeds that are more at risk for squamous cell carcinoma include:

  • Dalmatians.
  • Bull Terriers.
  • Beagles.

Mast Cell Tumors

Mast cell tumors may be the most common form of skin cancer for dogs. About 20% of all skin cancer found in dogs originates in mast cells [2]. Don’t worry too much, though, as most dogs will recover from mast cell tumors with the right treatment.

Mast cells are a type of white blood cell associated with the immune system [3]. That association can be a problem as if cancer spreads from mast cell tumors to the lymph nodes, it has the potential to spread throughout the body.

Mast cell tumors are more likely to occur in:

  • Retrievers.
  • Boston Terriers.
  • Boxers.
  • Pugs.

Malignant Melanomas

Malignant melanoma typically occurs around a dog’s mouth, though malignant melanomas can also appear around the eyes, ears, paws, and skin [4]. As with humans, malignant melanoma can be one of the more dangerous types of skin cancer in dogs. However, most melanomas in dogs are benign.

Malignant melanomas are typically associated with sun exposure and light-colored fur. However, malignant melanoma is also found in dogs with darker fur, such as Schnauzers and Scottish Terriers. Some of the breeds that are prone to developing malignant melanomas include:

  • Airedale, Scottish, and Boston Terriers.
  • Retrievers.
  • Boxers.
  • Poodles.
  • Spaniels.

Histiocytic Cell Tumors

Histiocytic sarcoma is a form of cancer that can appear in several places throughout the body, including the bones, skin, and joints [5].

Histiocytic skin cancers are more likely to be localized, which is the most treatable kind. In general, however, the prognosis for this type of skin cancer in dogs is often grave.

Breeds that are more likely to develop histiocytic skin tumors include:

  • Bernese Mountain Dogs.
  • Flat-Coated, Labrador, and Golden Retrievers.
  • Rottweilers.
  • Schnauzers.
  • Corgis.

Fibrosarcoma

Fibrosarcoma is one type of a larger category called soft tissue cancers [6]. This type of tumor can appear in a few parts of the body, including on the skin, muscle, and tendons [7].

Soft tissue skin cancers tend to be easy to treat, as they spread slowly and can be removed surgically. However, they do tend to reappear and have to be removed again. Visible tumors found in dogs might be firm to the touch or rubbery and anywhere from gray to red in color.

Fibrosarcoma
The metastatic rate (spread) of STSs in dogs is relatively low, particularly in low grades cancers

What Causes Skin Cancer in Dogs?

The causes of any cancer are usually tough to determine. Mast cell tumors, squamous cell carcinomas, and other tumors are caused by cell damage, which accumulates over the years and increases your pet’s risk gradually.

Unsurprisingly, skin cancers are often associated with damage to the skin, though not usually the damage that comes with normal bumps and bruises. Malignant melanoma is usually associated with exposure to the sun, for example. There may be no one event that can be pointed to as the reason a dog may get skin cancer.

Statistically, dogs between 6 and 10 years of age are the most likely to develop one of several kinds of skin cancers. Cancer is generally rarer in a younger pet. On the other end of the scale, a malignant tumor would already have grown on an older dog’s skin if it was going to.

Risk factors can include a variety of things, for example:

  • Genetics.
  • Exposure to radiation, including sunlight.
  • Repeated swelling or injury.
  • Exposure to chemicals.

What Breeds of Dogs Get Skin Cancer?

Perhaps due to genetic risk factors, some breeds of dogs are more prone to some forms of cancer. We’ve already listed some of the breeds that are more likely to develop one type of skin cancer or another.

In general, however, purebred dogs are more likely to develop some type of cancer in their lifetimes [8]. Due to the breeding process, undesirable attributes like being prone to cancer become more likely.

What Breeds of Dogs Get Skin Cancer
The Irish water spaniel and flat-coated retriever showed to be more prone to cancer and cancer-related deaths

Dogs with light-colored fur or no fur can also be prone to developing malignant melanomas, for example, Bull Terriers. With less fur comes less protection against UV radiation. However, some dogs are at an increased risk even if they have dark fur, such as Schnauzers and Scottish Terriers.

Symptoms of Skin Cancer in Dogs

One of the most common warning signs of cancer in dogs is a skin growth. It might be wart-like or maybe more like a mole, as that’s what it basically is.

Many tumors are benign, meaning that they’ve already grown as much as they’re going to. As a result, they don’t present any danger. As we’ve mentioned, about half of tumors tested end up being benign.

Those odds aren’t any better than flipping a coin. When you see a growth, don’t gamble. It’s best to get a vet to look at it.

What Does Skin Cancer in Dogs Look Like?

Most types of skin cancer will start out looking like some sort of growth or wart. Most often, they will be quite small and may appear suddenly. They can be tough to spot under fur, and you may not notice them initially. You are more likely to feel them as lumps or bumps.

Cancer may also appear as a sore, though that is more likely as the cancer grows.

What Does a Cancerous Growth Look Like On a Dog?

Skin cancer in dogs might be more wart-like and odd-looking or appear as raised, brown spots. Growths can vary in shape, texture, and color. Some general characteristics to look for include:

  • Squamous cell carcinomas often appear as raised lumps. The lumps are liable to develop sores or plaque, a medical term meaning red and lumpy, with whitish scales.
  • Mast cell tumors are more likely to appear as growths beneath the skin. They can be large or smaller, firm or pliable.
  • Melanomas may be easier to spot. They tend to be flatter, wide, and brown. Some can be smaller and darker.
  • Hystiocytmoas usually appear as singular lesions somewhere on the dog’s body. These are commonly found on the head or ear.
  • Fibrosarcoma growths might appear as grey or white, shading to red. They may be either rubbery or firm to the touch.

Dog Skin Growths Pictures

Diagnosing Dog Skin Cancer

The only way to diagnose skin cancer in dogs for certain is to take your pet to the vet. The vet will most likely perform a physical examination. If they think it’s necessary, the veterinarian will also perform a biopsy.

Diagnosing-Dog-Skin-Cancer

Physical Examination

While a physical examination can’t positively identify whether your dog has cancer, it can still provide a lot of information. The veterinarian may look for more lumps and bumps in case there might be other tumors elsewhere.

It’s also important to assess the dog’s overall health, as that can have an effect on prognosis and treatment options.

Biopsy

The actual diagnosis will most likely be made after some tissue is extracted from the growth and tested. This process is called a biopsy.

The veterinarian will take a small sample via a method called fine-needle aspiration in which a few cells are removed. Fine needle aspiration is very safe and may be done with only a local anesthetic or no anesthetic.

A biopsy sample is then usually sent to a lab for testing, with results returning within a few days. Cancer might also be diagnosed through blood tests or X-rays.

Dog Skin Cancer Treatment

A lot of the same treatment options that work for humans also work on dogs. Most dogs will be treated with some combination of surgery, radiation, or chemotherapy.

Surgery

Surgical removal of a tumor is probably the most common skin cancer treatment and may be the only treatment required.

Depending on the variety of skin cancer, there may be a chance the tumor will reappear. For that reason, surgery may be combined with other treatments.

Chemotherapy

Chemotherapy involves various drugs (or chemicals, though that doesn’t sound as nice) that are used to target the tumor [9]. These can have a variety of effects but are mostly aimed at:

  • Halting the growth of the tumor.
  • Reducing the size of the tumor.

There can be some serious downsides that come with chemotherapy, as it basically involves giving your dogs chemicals that would otherwise be considered toxic. However, chemotherapy can be very effective. Note that some of these medications can be toxic to you too and should be handled with care.

Steroids

Using steroids as a cancer treatment is a subtype of chemotherapy. The steroids used are similar to the cortisone shot your grandfather gets in arthritic joints. Benefits include:

  • Possibly reducing the size of the tumor.
  • Possibly halting the growth of the tumor.
  • Managing other symptoms like pain or stomach upset.

While they can be used on their own, your dog is more likely to get steroids after surgery to remove skin tumors [10].

Radiotherapy

Radiotherapy, or radiation therapy, is often used to treat skin cancer as part of a larger treatment plan that includes a few different strategies [11]. As technology has advanced, radiation therapy has become very precise, which can reduce side effects.

Clinical Trials for Dogs with Skin Cancer

Since many of the same treatments that work on humans also work on dogs, advances in medical science have benefited our furry friends. While still being researched, there are a few treatments that have been effective.

Clinical-Trials-for-Dogs-with-Skin-Cancer

Immunotherapy

Cancer cells started out as regular dog cells, and as a result, the dog’s body has a hard time telling them apart. A tumor can also suppress your dog’s immune system.

Immunotherapy focuses on supporting the dog’s immune system and helping it target the cancer cells [12]. At the moment, immunotherapies are still being evaluated for dogs. It’s pretty cutting edge and may not be available everywhere and limited to only a few types of cancer, including melanomas.

Electrochemotherapy

It may seem a little mad scientist, but adding electric shocks actually does help. In some cases, chemotherapy treatments can be combined with electric shocks [13]. As a result, the barrier that divides cancer cells from the rest of the body and can block the chemotherapy drugs becomes more permeable.

This treatment has found some success with mast cell tumors, squamous cell carcinoma, and malignant melanoma.

How Long Can Dogs Live With Skin Cancer?

It’s impossible to say how long a dog may be able to live with skin tumors. Tumors start small and grow over time, during which the dog may not be bothered at all. However, the longer it goes untreated, the more likely it is going to spread to other organs. Tumors can also become uncomfortable quickly.

When tumors spread to lymph nodes, they can quickly travel to other lymph nodes, and from there, throughout the body. At that point, your dog faces an increased risk of serious health problems.

How Long Can Dogs Live With Skin Cancer
Dogs with a mitotic count of >10/10 HPF usually don’t survive longer than 1000 days

Sometimes, dogs may be considered to be living with tumors after treatment. It’s tough to say when cancer is ‘cured,’ which means tumors will definitely not return. More often, it is said to be in remission, in which a tumor has been removed, but there remains an increased risk for developing tumors [14].

How To Care for a Dog With Skin Cancer

It may go without saying, but the best way to care for a dog with skin cancer is to take it to a veterinarian. As we’ve discussed, the treatments can be pretty aggressive. A veterinarian has the training and experience to apply them in an effective way.

There are some alternative treatments that people recommend. Discussing options with a vet is, again, probably the best way to go. You can also do some things to make your furry friend more comfortable, both before and after treatment.

How To Treat Dog Tumors at Home

When you’re trying to care for a sick dog, life can be pretty tough. Your pet can’t do all of the things they are used to doing, as well as not feeling well.

Your vet will probably have some directions. There are also some over-the-counter products that may help. A topical CBD cream can help reduce pain and inflammation, for example.

What may be more important is your attitude and outlook. If you’re stressed and unhappy, your dog probably will be too. A more positive outlook can help them be more at ease [15].

It’s also important to be realistic. While dogs can live for years after being treated for cancer, in some cases, you may be buying some extra time to love your pet and say goodbye.

FAQ

Is Skin Cancer Painful for Dogs?

When tumors first appear, they are relatively small, and the dog may not even notice they are there. However, as they grow and spread, they can become uncomfortable or painful.

Can Dogs Die From Skin Cancer?

Unfortunately, cancer is a very serious condition. Tumors can spread to other organs, impeding their function or stopping it altogether. As a result, untreated tumors can lead to death.

Can Dog Skin Cancer Be Cured?

Cured, when speaking about cancer, means the tumors are gone and aren’t going to come back. It’s difficult to know that for certain. Remission is more likely, in which the tumors are gone but still have the potential to grow back.

Can a Dog Live With Skin Cancer?

Skin cancer can be treated successfully so that a dog can be happy and healthy once more. It’s not something that will resolve on its own and will require treatment, however.

Conclusion

It’s hard not to look at the newly discovered pimple on your dog and wonder if it’s the big C, particularly as they get older. However, with early detection and the right treatment, your dog can still live a long, happy life.

References:

  1. “5 Types of Skin Cancer in Dogs.” North Carolina University College of Veterinary Medicine, cvm.ncsu.edu/wp-content/uploads/2018/03/5-Types-of-Tumors.pdf.
  2. Garrett, Laura D. “Canine Mast Cell Tumors: Diagnosis, Treatment, and Prognosis.” Veterinary Medicine (Auckland, N.Z.), Dove, 12 Aug. 2014, www.ncbi.nlm.nih.gov/pmc/articles/PMC7337164/.
  3. “NCI Dictionary of Cancer Terms.” National Cancer Institute, www.cancer.gov/publications/dictionaries/cancer-terms/def/mast-cell.
  4. Nishiya, Adriana Tomoko, et al. “Comparative Aspects of Canine Melanoma.” MDPI, Multidisciplinary Digital Publishing Institute, 19 Feb. 2016, www.mdpi.com/2306-7381/3/1/7/htm.
  5. “Canine Histiocytic Sarcoma.” NC State Veterinary Medicine, 22 Nov. 2019, cvm.ncsu.edu/nc-state-vet-hospital/small-animal/oncology/canine-histiocytic-sarcoma/.
  6. Simeonov, R., et al. “[PDF] Prevalence of Canine Epithelial, Melanocytic and Mesenchymal Tumours of the Skin and Soft Tissues: a 10-Year Study.: Semantic Scholar.” Undefined, 1 Jan. 1970, www.semanticscholar.org/paper/Prevalence-of-canine-epithelial%2C-melanocytic-and-of-Simeonov-Dinev/8c91043c223eb709c9b4a2a3871ab90246d458d0.
  7. Simeonov, R., et al. “[PDF] Prevalence of Canine Epithelial, Melanocytic and Mesenchymal Tumours of the Skin and Soft Tissues: a 10-Year Study.: Semantic Scholar.” Undefined, 1 Jan. 1970, www.semanticscholar.org/paper/Prevalence-of-canine-epithelial%2C-melanocytic-and-of-Simeonov-Dinev/8c91043c223eb709c9b4a2a3871ab90246d458d0.
  8. Baioni, Elisa, et al. “Estimating Canine Cancer Incidence: Findings from a Population-Based Tumour Registry in Northwestern Italy.” BMC Veterinary Research, BioMed Central, 28 June 2017, www.ncbi.nlm.nih.gov/pmc/articles/PMC5490209/.
  9. “Chemotherapy Fact Sheet.” North Carolina State University College of Verterinary Science, cvm.ncsu.edu/wp-content/uploads/2018/03/Chemo-Fact-Sheet.pdf.
  10. McCaw, Dudley L., et al. “Response of Canine Mast Cell Tumors to Treatment With Oral Prednisone.” Wiley Online Library, John Wiley & Sons, Ltd, 28 June 2008, onlinelibrary.wiley.com/doi/abs/10.1111/j.1939-1676.1994.tb03259.x.
  11. “NC State Veterinary Hospital Radiation Oncology.” NC State Veterinary Medicine, 19 Sept. 2019, cvm.ncsu.edu/nc-state-vet-hospital/small-animal/radiation-oncology/.
  12. “Immunotherapy.” North Carolina State University College of Veterinary Medicine, cvm.ncsu.edu/wp-content/uploads/2018/04/Immunotherapy-Med-Onc-4.19.18.pdf.
  13. “Electrochemotherpay: the New Wave of Cancer Treatment?” North Carolina State University College of Veterinary Medicine, cvm.ncsu.edu/wp-content/uploads/2018/04/Electrochemotherapy-MED-ONC.pdf.
  14. “Can Cancer Be Cured?” American Cancer Society, www.cancer.org/treatment/understanding-your-diagnosis/can-cancer-be-cured.html.
  15. Ehrhart, Dr. Nicole. “10 Things To Do When Your Pet Gets Cancer.” Flint Animal Cancer Center, 16 July 2020, www.csuanimalcancercenter.org/2019/11/14/when-your-pet-has-cancer/.