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Do Cancerous Lumps Hurt Dogs?



Reviewed By: Dr. Joel Robertson

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Do cancerous lumps hurt dogs It is a question many pet owners have when they encounter an unfamiliar lump on their dog?

We will discuss how to identify whether a lump is benign or malignant, as well as what treatments may be available for dog owners should their pup be diagnosed with cancer.

By understanding more about canine cancer and how it affects our beloved four-legged friends, we can help ensure that any medical treatments are tailored to each individual’s needs.

Key Takeaway

  • While some cancerous lumps may cause pain or discomfort in dogs depending on their location and rate of growth, others might not cause any noticeable discomfort at all.
  • A cancerous lump on a dog might appear as a raised, firm, irregular, and potentially ulcerated area that could be big or small, soft or hard, flat or raised, often differing from benign lumps like lipomas which are soft and fatty.
  • Cancerous lumps in dogs are abnormal growths that can vary in appearance and texture, often appearing as raised, hard, wart-like patches or nodules, which may be malignant and potentially harmful, resulting from conditions like skin squamous cell carcinoma, osteosarcoma, or mast cell tumors.

What Are Cancerous Lumps In Dogs?

What Are Cancerous Lumps In Dogs

Cancerous lumps in dogs can take various forms and originate from different types of cells.

Some common types include skin squamous cell carcinoma, which appears as raised wart-like patches, and osteosarcoma, a malignant cancer arising from bone cells that often causes pain and can result in fractures.

Another common type is a mast cell tumor, a malignant growth consisting of mast cells that typically form nodules or masses in the skin. It’s important to note that not all lumps are cancerous.

Many are benign fatty tumors or lipomas. Cancerous tumors tend to be harder than lipomas and are usually not hot or sensitive to the touch.

However, any new or changing lump on a dog should be evaluated by a veterinarian to determine its nature.

Do Cancerous Lumps Hurt Dogs?

Yes. Cancerous lumps that grow quickly and are located in sensitive areas and are irritated by the dog’s activities will cause pain to dogs.

These lumps, or tumors, are typically harder than non-cancerous lumps like lipomas and are not typically hot or sensitive to the touch.

However, some cancerous skin growths may itch or hurt, while others may not bother the dog at all. Mast cell tumors, a common type of skin cancer in dogs, can grow quickly and may be red and itchy.

In some cases, dogs may chew or bump these masses, causing them to bleed.

That said, the presence of a lump on a dog’s body doesn’t automatically indicate cancer, but any new growth should be checked by a vet to rule out the possibility.

What Does a Cancerous Lump Look Like on a Dog?

Cancerous lumps on a dog can appear as raised, wart-like patches that are firm to the touch and are often found on the dog’s head and lower legs.

Others might be harder and more immovable compared to benign lumps like lipomas, which are soft and fatty.

Mast cell tumors and carcinomas, which are malignant, do not have a typical look and feel; they could be big or small, soft or hard, flat or raised.

Tumors caused by prolonged sun exposure may produce multiple irregular, raised, and ulcerated areas.

What Causes Cancerous Lumps In Dogs?

  • Papillomas: Also known as warts, these are benign tumors caused by the canine papillomavirus. The virus is usually transmitted from one dog to another through contact.
  • Malignant Melanoma: These are raised bumps that can be dark-pigmented (but not always) and are frequently found around the dog’s lips, mouth, and other areas. Unlike human melanomas, canine melanomas are not caused by sunlight and are less malignant.
  • Sudden Appearance of Lumps: Sudden appearance of large lumps that change in size, color, and texture could be indicative of cancerous growths. Any discharge from these lumps should also be a cause for concern.
  • Genetic or Hereditary Factors: Some cancerous lumps in dogs seem to be caused by a complex mix of risk factors, some environmental and some genetic or hereditary. Several genetic mutations are known to be involved in the development of mast cell tumors, for instance.
  • Abnormal Cell Growth: In general, tumors are caused by an abnormal growth of the cells in the skin or tissue of your dog. The root causes can be diverse, ranging from genetic predisposition to environmental factors.

Symptoms of Cancerous Lumps In Dogs

  • Abnormal swellings or lumps that persist or continue to grow
  • Sores that do not heal
  • Foul-smelling discharge from the mouth, nose, or eyes
  • Non-healing wounds or sores
  • Abnormal odors from the mouth, ears, or other parts of the body
  • Uneven growth of the testicles (in the case of testicular cancer)
  • Lethargy or decreased activity levels
  • Difficulty eating or loss of appetite
  • Weight loss
  • Coughing or exercise intolerance
  • Bleeding or discharge from any body opening
  • Vomiting or diarrhea

How To Help a Dog With Cancerous Lumps

Here is how to help a dog with cancerous lumps:

Regular Check-ups and Early Detection

One of the most effective ways to help a dog with cancerous lumps is by conducting regular check-ups and early detection.

Most dogs will develop lumps and bumps over their lifetime, and it’s essential to catch these as early as possible. Regular vet check-ups and grooming services can help identify any abnormalities that may not be noticeable at home.

Surgical Removal

For some types of tumors that are locally invasive, surgical removal can be an effective treatment. This involves removing both the tumor and some surrounding tissue to prevent recurrence. However, this method is usually recommended for tumors that haven’t spread to other parts of the body.

Chemotherapy and Radiation Therapy

In cases where cancer has spread or the tumor cannot be completely removed surgically, chemotherapy and radiation therapy may be recommended.

These treatments aim to kill cancer cells and prevent them from growing and spreading further. For higher-grade tumors, a combination of surgery and chemotherapy is often recommended, even without evidence of spread.


Immunotherapy is another treatment option for dogs with cancerous lumps. This involves using the dog’s immune system to fight cancer cells. It can be used alone or in combination with other treatments like surgery, chemotherapy, or radiation therapy.

Behavioral Changes and Supportive Care

If you suspect your dog has cancer, whether from finding a lump or witnessing behavioral symptoms, it’s crucial to contact your vet immediately. Providing supportive care, managing pain, and monitoring your dog’s behavior can help improve their quality of life during treatment.


Q: What are the common types of lumps in dogs?

A: There are many different types of lumps that can occur in dogs. Some common types include fatty tumors (lipomas), mast cell tumors, cysts, and cancerous tumors.

Q: What are the warning signs of cancer in dogs?

A: The warning signs of cancer in dogs can vary depending on the type and location of the cancer. Some common symptoms include the presence of a lump or bump, unexplained swelling, changes in the size or shape of a lump, sores that do not heal, weight loss, decreased appetite, lethargy, and abnormal bleeding.

Q: When should I see a veterinarian if I find a lump or bump on my dog?

A: It is recommended to see a veterinarian as soon as possible if you find a lump or bump on your dog. The veterinarian will be able to examine the lump and perform necessary tests such as a biopsy to determine if it is cancerous or benign.

Q: Can lumps on dogs be a sign of cancer?

A: Yes, lumps on dogs can be a sign of cancer. While not all lumps are cancerous, it is important to have any new or suspicious lump examined by a veterinarian to rule out the possibility of cancer.

Q: How common is cancer in dogs?

A: Cancer is a prevalent disease in dogs, particularly in older dogs. It is estimated that about one in three dogs will develop some form of cancer during their lifetime.

Q: Can cancer spread to other parts of the dog’s body?

A: Yes, cancer can spread to other parts of a dog’s body. This process, known as metastasis, occurs when cancer cells break away from the primary tumor and travel through the bloodstream or lymphatic system to establish new tumors in different organs or tissues.

Q: What should I do if I suspect my dog has cancer?

A: If you suspect your dog has cancer, it is important to consult with a veterinarian. The veterinarian will perform a thorough examination and may recommend further diagnostic tests such as blood work, imaging, or a biopsy to confirm the diagnosis and determine the appropriate course of treatment.

Q: Can cancer in dogs be treated?

A: Yes, cancer in dogs can be treated. The treatment options for cancer in dogs vary depending on the type and stage of the cancer. Common treatment modalities include surgery, chemotherapy, radiation therapy, and immunotherapy. The veterinarian will discuss the treatment options and prognosis with you based on your dog’s specific condition.

Q: Are lumps beneath the skin always cancerous?

A: No, lumps beneath the skin are not always cancerous. There are many different causes for lumps beneath the skin in dogs, ranging from benign tumors to cysts or abscesses. The only way to determine the nature of the lump is through a veterinary examination and possibly a biopsy.

In Conclusion

The pain associated with a lump will depend on its location, size, and type.

If you suspect that your dog has a cancerous lump, it is important to take them to the vet for proper diagnosis and treatment as soon as possible.

With early detection and proper treatment, many types of cancer can be managed or even cured in dogs.

Please take the time and leave a comment below if this article helped you, or you have any additional questions.

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