Types of Dog Cancer and Their Severity

The American Kennel Club Canine Health Foundation estimates that one in four dogs, or 25% of all canines, will develop cancer at some point in their lives. The good news is that most types of cancer are treatable. When caught early, many can be cured. No matter the type of cancer you suspect your dog may have, it’s important to seek a diagnosis and treatment immediately. Below are the seven most common types of dog cancer, as well as how they affect your pup long-term and what treatment options exist.

Bladder cancer

Bladder cancer is the most common type of canine cancer, and it occurs when cells in one or more parts of the bladder become abnormal. This can happen on its own or as a result of another disease. There are two main types: primary and secondary.

Primary bladder cancers occur spontaneously without any known cause, without having been preceded by some other disease process. Secondary bladder tumors develop as a result of an underlying condition that affects the bladder’s tissue structure, such as inflammation from chronic cystitis (a bacterial infection), radiation therapy for other cancers, or trauma to the area during surgery (such as spaying).

Bladder tumors can also be either malignant or benign. Malignant tumors grow quickly and invade nearby areas; they may spread to other parts of your pet’s body through lymph nodes or blood vessels. Benign tumors are not cancerous but still need attention because they can grow large enough over time to affect organ function

Bone cancer

Bone cancer is rare in dogs, but it does occur.

  • The average age of affected dogs is about 11 years old, with a range of 6 to 15 years old.
  • Bone cancer most often occurs in older pets, but younger dogs can also be affected.
  • This type of cancer most often affects large breed dogs and boxers, as well as some other breeds including Bernese mountain dogs and cocker spaniels.

Bone cancers can be surgically removed if possible, and radiation therapy may also be an option depending on where the tumor is located within the bone or if other treatments are not feasible due to an animal’s overall health status or size/weight considerations. Chemotherapy has been used with some success as well; however it can have side effects such as nausea, vomiting and loss of appetite that make treating small animals difficult without sedation or anesthesia first being administered by your veterinarian before giving them any medications orally at home afterward during recovery time where needed post surgery instead during recovery time when needed post surgery instead during recovery time after surgery which may take longer than expected depending on how much medication had been given before hand because some pets might require more than others due to differences between species versus breeds from one another even though certain breeds tend towards certain illnesses more often than others do according

Breast cancer

Most dogs do not get breast cancer. Breast cancer is rare in canines, and it’s not hereditary. Furthermore, while it may be tempting to blame your dog’s diagnosis on diet or stress, there’s no evidence that these factors cause canine breast cancer.

Breast cancer has been documented in both male and female dogs as well as cats, but it affects more females than males — three times more often in dogs versus one-tenth as much in cats (according to the ASPCA).


Lymphoma is a cancer that begins in lymphocytes, the white blood cells that defend your dog’s body against infection and disease. Lymphoma can affect any part of the body but most commonly affects the lymph nodes. It may also occur in bone marrow, spleen, liver and other organs.

Lymphoma can be caused by infections with viruses such as Epstein Barr virus (EBV) which causes mononucleosis in humans but also causes lymphosarcoma in dogs. Other causes include immunodeficiency diseases like feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV). Signs include enlarged lymph nodes near the neck or underarm area; fever; weight loss; anemia; lethargy and increased thirst or urination (polydipsia). Treatment options include chemotherapy drugs injected into your pet’s bloodstream through an IV line placed either surgically or via a catheter inserted under anesthesia into a vein on their leg or arm at home during hospitalization if necessary depending on where tumors are located within body system(s); radiation therapy used most often when tumors are localized to one area such as lungs heart liver pancreas intestines etc.; surgery if only one organ has been affected by cancer tumor growths


Hemangiosarcoma is a type of cancer that affects the blood vessels. It’s the most common cancer in dogs and affects deep-seated organs like the spleen or liver, as well as outer areas like skin, heart and muscle tissue. Hemangiosarcomas are most common in large breed dogs (e.g., boxers) and usually occur between ages 10 and 14 years old; however, some smaller breeds have been known to develop hemangiosarcoma at very young ages (as early as one year). Males are more likely than females to develop this type of tumor; they can also spread quickly throughout your pet’s body if left untreated.


A form of skin cancer, melanoma can be treated if caught early. But if it spreads to other organs, it’s fatal. The most common cause of melanoma in dogs is exposure to ultraviolet light from the sun or indoor bulbs. If your dog has white fur, he’s more likely to develop this type of cancer than a pup with darker hair.

It’s important to note that not all white-haired dogs will get melanoma—and not all dark-haired dogs won’t! So don’t think that your pal is safe just because they’re black or brown.

Squamous cell carcinoma

You may have heard of sarcoma, or cancer of the bone. But did you know that “sarcoma” is a general term for several types of cancers? This includes:

  • Cancer of the red blood cells (erythrocytic leukemia)
  • Cancer of the white blood cells (leukocytic leukemia)
  • Cancer of the lymphatic system (lymphosarcoma)
  • Cancer of bone marrow (myelogenous leukemia)

Some forms are more common than others, and each has their own symptoms and treatment options. These include:

Skin cancer (mast-cell tumor)

Mast-cell tumors are common in dogs. They are usually malignant and can spread to other parts of the body, including the eyes, lungs, liver, intestines and lymph nodes. Mast-cell tumors are most often found on the skin and head area. Sometimes they’re also found on the ears or eyelids.


We’ve covered a lot of information so far, and you may be wondering what to do next. If your dog has cancer, keep in mind that the earlier it is diagnosed, the better chance there is of recovery. Early detection is key to fighting cancer in dogs. This means that if you see any symptoms at all (especially those we’ve listed above) you should schedule an appointment with your veterinarian right away.