13 Types of Cancer in Dogs

Types of Cancer in Dogs

Dogs, like their human counterparts, are susceptible to several cancers, including lymphoma and even breast cancer. The good news is that veterinary oncology treatments are similar to those used to treat cancer in humans. We have compiled a list of 13 types of cancer in dogs to help you learn about which ones could affect your beloved pup.

While this is not a definitive list, here are some of the different types of cancer that can affect dogs.

Types of Cancer in Dogs

Similar to humans, there are different types of cancer in dogs, including:

Anal Sac Cancer in Dogs

Anal sac cancer is a rare, aggressive form of cancer that affects a dog’s anal glands. The anal glands are small pouches located on either side of the anus that produce a musky scent.

Anal sac cancer is a type of adenocarcinoma, which is a cancer that begins in cells that line body cavities and organs. Anal sac adenocarcinoma can also develop in other parts of the body such as the colon or rectum.

Anal sacs are located under the skin on either side of the anus and produce secretions that are released when your dog has bowel movements. Dogs typically don’t have any symptoms until they reach advanced stages of disease or the tumors become very large. Treatment options include surgery, chemotherapy and radiation therapy.

Signs of anal sac cancer in dogs includes:

  • A swollen or firm lump in one or both of your dog’s anal sacs
  • Blood in the stool or around the anus
  • Difficulty urinating or defecating (constipation)
  • Loss of appetite and weight loss
  • Your dog may lick at their anus frequently

Bladder Cancer in Dogs

There are a few different types of tumors that can cause bladder cancer in dogs. The most common, transitional cell carcinoma (TCC), develops in the deep portions of the bladder wall. As the tumor grows, it may invade the urethra and obstruct urine flow, resulting in difficulty urinating or total blockage.

Bladder cancer is more common in older and elderly female dogs, but it can affect any breed. Shetland Sheepdogs, Scottish terriers, Firehair Fox Terriers, West Highland Terriers, and Beagles are the breeds most usually affected.

Signs of bladder cancer in dogs include:

  • Blood in the urine
  • Urinating outside the box
  • An increase in urination (frequent urination)
  • Hesitation before urinating
  • Painful or difficult urination
Bladder cancer in dogs
Bladder Cancer in Dogs

Hemangiosarcoma in Dogs

Hemangiosarcoma is a type of cancer that arises from blood arteries, with tumors most commonly found in the spleen, liver, skin, and heart. This type of cancer can spread to any part of the body and is more common in middle-aged and older dogs.

Hemangiosarcoma can strike any dog breed, although it’s most frequent in German Shepherds and Golden and Labrador Retrievers. This sort of cancer appears to be prone in males as well.

The most common sign of hemangiosarcoma in dogs is a lump or swelling under your dog’s skin. If you notice one, it’s important to get it checked out by your veterinarian immediately so that the tumor can be biopsied and diagnosed as early as possible. Additional signs include:

  • Lumps or swellings on your dog’s body
  • Pale gums or other discoloration near the tumor
  • Vomiting, loss of appetite or weight loss
  • Anemia (low red blood cell count) or bruising easily
  • Abdominal swelling or distention

Liver Cancer in Dogs

Because evident clinical indications are not always present, liver cancer can be a silent killer in dogs. This type of cancer can be caused by a variety of malignant tumors, however, it is most commonly caused by a single big tumor called hepatocellular carcinoma. This tumor only affects the liver and seldom spreads to other regions of the body.

Liver cancer can affect any breed and usually affects older dogs, although it has been known to occur in younger dogs.

Early signs of liver cancer include:

  • Loss of appetite
  • Weight loss
  • Vomiting
  • Diarrhea

As liver cancer progresses, additional symptoms may develop including:

  • Jaundice (yellowing of the skin)
  • Increased thirst and urination
  • Abdominal swelling due to fluid buildup

Lymphoma in Dogs

Lymphoma is a disease of the lymph nodes and lymphatic system that is one of the most commonly diagnosed tumors in dogs. Lymphoma in dogs can affect a variety of organs, but it is most usually discovered in the peripheral lymph nodes, which are deep within the subcutaneous tissue (the innermost layer of the skin). 

This form of cancer affects dogs of any age and breed, however, it’s most commonly found in Golden Retrievers and dogs between the ages of 6 and 9. 

Signs of lymphoma in dogs include:

  • Swollen lymph glands
  • Hair loss or skin sores that don’t heal
  • Fever, weight loss, vomiting and diarrhea
  • Abnormal bleeding (such as rectal bleeding)

Breast Cancer in Dogs

This type of cancer affects the mammary glands in the same way as it affects humans. There are ten mammary glands in dogs, which are arranged in two rows from the chest to the belly wall. Tumors can form in either of these glands, although the two nearest to the hind legs are most usually affected.

The three main types of mammary cancer are:

  • Adenocarcinoma. This type of tumor develops from the glandular tissue that makes up the bulk of the breast.
  • Lobular carcinoma. This type of tumor forms in the milk-producing cells that line the lobules (the smallest parts) of the breast.
  • Mixed adenocarcinoma-lobular carcinoma. This type of tumor has both types of cancerous cells in it.

Older female dogs are at higher risk of developing mammary tumors, particularly those that are unspayed or were spayed after 2 years of age. Breeds known to be at higher risk of developing mammary tumors include Poodles, Terriers, English Spaniels, and English Setters.

Signs of mammary cancer in dogs include:

  • Lumps or bumps in your dog’s mammary glands
  • A change in size or firmness of one (or more) of your dog’s mammary glands
  • A change in coloration or texture of one (or more) of your dog’s mammary glands

Mast Cell Tumors in Dogs

Mast cell tumors (MCTs) are cancerous masses generated by usually healthy cells that have gathered together and formed a mass. The most common site for these tumors is the skin, but they can also affect other regions of the body. The respiratory and digestive tracts are included. MCTs in dogs may be quite harmless and curable with surgery. They can, however, be quite aggressive and spread to other parts of the body in other cases.

Although mass cell tumors can develop in dogs of any age, they are more common in older dogs, with Boxers, Bull Terriers, Boston Terriers, and Labrador Retrievers being the more susceptible breeds.

Signs of mast cell tumors include:

  • Swelling around the tumor site
  • Lump or bump on your dog’s skin
  • Redness around the tumor site
types of cancer in dogs
Boston Terrier

Melanoma in Dogs

Melanoma is a type of skin cancer that develops from melanocytes, which are the skin cells responsible for creating pigment in the nails, skin, and eyes. Despite the fact that these tumors are most typically discovered as masses or lumps on the skin, they have a high proclivity for spreading and can affect other regions of the body. They also have a proclivity for bleeding as they develop.

Melanoma can affect dogs of any breed but is more commonly seen in Chow Chows, Cocker Spaniels, Poodles, and Schnauzers.

Signs of melanoma in dogs include:

  • Sores that won’t heal
  • Scabs or crusty areas that bleed when scratched
  • Solid black patches of skin that don’t go away after a few days
  • Small tumors (usually less than an inch wide) that grow rapidly

Oral Melanoma in Dogs

The most prevalent type of oral tumor in dogs is this type of cancer, which involves cancers that damage the mouth cavity. Melanoma can form on the gums, lips, and other oral tissues. The tumors might be benign or cancerous, and they normally grow, causing discomfort and eating difficulties.

Oral melanoma is more common in elderly dogs that have darker pigmentation in their mouth. Boxers, Chow Chows, Cocker Spaniels, German Shepherds, German Shorthaired Pointers, Golden Retrievers, Gordon Setters, Miniature Poodles, and Weimaraners are among the breeds at risk.

Oral melanoma in dogs can be difficult to detect because it usually does not cause any symptoms until it has reached an advanced stage. The most common sign of oral melanoma is an ulcer that lasts longer than two weeks and does not heal by itself. Other signs include:

  • A lump or bump on your dog’s lips or mouth
  • Bleeding from the mouth or gums
  • Pain when eating or chewing

Stomach Cancer in Dogs

Stomach cancer is not the most frequent type of cancer in dogs, but it is one of the most deadly. This type of cancer usually does not present any signs until it has grown to an advanced stage. Stomach cancer in dogs is caused by a variety of tumors, most of which are malignant and can spread to other parts of the body.

This type of canine cancer is most commonly found in older male dogs. Breeds known to be predisposed to this type of cancer include the Rough Collie, Staffordshire Bull Terrier, Belgian Shepherd Dog, and Chow Chow.

Signs of stomach cancer in dogs include:

  • Vomiting
  • Loss of appetite (anorexia)
  • Weight loss
  • Diarrhea
  • Painful abdomen (colic)
stomach cancer in dogs
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Soft Tissue Sarcoma in Dogs

This is a common cancer in dogs that is made up of a range of malignant tumors that damage the body’s connective tissues, such as fat muscles and cartilage. They often manifest as non-painful lumps that can emerge anywhere on the body, but most commonly on the limbs, chest, or abdominal wall.

Soft tissue sarcoma can affect dogs of any age and breed but is most commonly diagnosed in older, large-breed dogs, with Golden Retrievers, Saint Bernards, and Doberman Pinschers known to be at higher risk.

Signs that your dog has soft tissue sarcoma include:

  • Pain when moving the leg
  • Swelling or bulge in the leg
  • Lameness
  • Tenderness when you touch the tumor area
soft tissue sarcoma in dogs
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Testicular Cancer in Dogs

Male dogs are affected by this type of cancer, which causes tumors to grow on the testicles. Testicular tumors are most common in dogs over the age of ten that are not neutered. They can, however, affect dogs of any age that are healthy, especially those who have undescended testicles, a condition known as cryptorchidism.

Breeds known to be predisposed to the condition include Afghan Hound, Boxer, Collies, German Shepherd, Maltese, Shetland Sheepdog, and Weimaraner.

The following are common signs of testicular cancer in dogs:

  • A swollen or enlarged testicle on one side
  • Painful or enlarged scrotum; the skin over the entire scrotum may be red and inflamed
  • Difficulty urinating or straining to urinate
  • Blood in the urine or bloody discharge from the penis

Thyroid Cancer in Dogs

Tumors of the thyroid, a gland in the neck that releases key hormones that govern metabolism and help control major body functions, are involved in this type of cancer. Thyroid cancer is virtually always cancerous, and it frequently spreads to the lungs and lymph nodes. They can also get into neighboring organs like the windpipe, blood vessels, and esophagus.

Fortunately, thyroid cancer is relatively uncommon in dogs, however, Beagles, Boxers, and Golden Retrievers between the ages of 9 and 11 are known to be at higher risk.

Signs of thyroid cancer in dogs include:

  • Weight loss, despite an increased appetite (polyphagia)
  • Increased thirst (polydipsia)
  • Excessive panting or drooling
  • Difficulty breathing or swallowing
  • A lump or mass on your dog’s neck

Recognizing the Warning Signs of Cancer in Dogs

Early detection is key to treating cancer in pets, so knowing how to recognize the warning signs is an important first step for pet owners.

Published by AmberLDrake

Dr. Drake is an award-winning author and well-known cancer specialist in her field. She is best known for her extensive research on canine cancer prevention and nutrition, her dedication to help dogs live a long, happy life, and for teaching veterinary medicine. As the CEO of Canine Companions Co., the Founder of Drake Dog Cancer Foundation and Academy, and the Co-Founder of Preferable Pups, in addition to being a respected figure in the dog world, she has earned the respect of thousands of dog lovers worldwide.

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