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Great Dane Cancer Symptoms

Great Dane cancer symptoms.

While having a sick dog is always difficult for pet owners, having your Great Dane diagnosed with cancer can be absolutely devastating. According to a study sponsored by the National Canine Cancer Foundation, one in three dogs will develop some type of cancer during their lifetime.

Sadly, Great Danes are considered a high-risk breed when it comes to canine cancer.

Common symptoms of cancer in Great Danes include weight loss or loss of appetite; unusual swelling or growths; bleeding or discharge from any part of the body; a change in odor; lethargy or loss of stamina; and difficulty breathing, swallowing, urinating or defecating.

Let’s take a look at these symptoms more in-depth, as well as the various types of cancer commonly seen in canines.

Symptoms of Great Dane Cancer

In the event that your Great Dane exhibits any of the following symptoms then it’s possible that they may have cancer.

  • Weight loss or loss of appetite
  • Sores
  • Unusual swelling or growths
  • Bleeding or discharge
  • Lethargy or loss of stamina
  • Difficulty breathing or swallowing
  • Difficulty urinating or defecating

Weight Loss or Loss of Appetite

Any sudden change in appetite, usually loss of it, is a reason to be concerned. With that, if your dog’s weight begins to change or fluctuate, this can also be a symptom of cancer or another disease.


Dogs can often get small cuts or sores—especially if they are rougher while playing.

However, should a sore or cut continue to remain open and not heal, this may be a sign of a blood disorder or cancer.

Unusual Swelling or Growths

Unusual swelling or growth is one of the major visual symptoms of cancer. These typically appear by your dog’s lymph nodes. This can be in the leg or armpit area, groin, under the chin, and on their throat.

If the abnormality continues to grow or remains present, your veterinarian may need to perform a biopsy to see if it is malignant or benign.

Bleeding or Discharge

Any type of bleeding or discharge from any opening—mouth, nose, rectum, etc.—may be cause for concern.

This can be a symptom of a tumor in an area that may be difficult for you to see.

Lethargy or Loss of Stamina

Any time your Great Dane is sick, they may become lethargic or lose their general level of stamina. Illness can be draining for them.

This is one of the more general symptoms and could be an indicator of any type of illness—not just cancer.

Difficulty Breathing or Swallowing

Difficulty breathing or swallowing can be indicators of oral or respiratory cancer.

There may be hidden tumors that are undetectable to dog owners, which can cause discomfort and harm to your Great Dane.

Difficulty Urinating or Defecating

Similar to difficulty breathing or swallowing, difficulty relieving themselves may also be signs of tumors impacting those systems and body parts.

Should there be any blood or strange discharge when your pet does urinate or defecate, that is also a cause for warning.

Causes of Great Dane Cancer

Many things about cancer are still a mystery. However, it is important to understand exactly what cancer is. Cancer is simply a mutation of cells.

The cells may grow uncontrollably, start growing in surrounding areas and, eventually, metastasize or spread throughout the body.

Some cancers are hereditary. Hereditary means the risk or disposition to getting that type of cancer was passed on genetically. This explains why some breeds, like Great Danes, are at a higher risk for developing cancerous cells.

Other cases of cancers are caused by environmental factors. Much like smoking may cause lung cancer in humans, external factors may cause your pet to develop cancerous cells.

Environmental factors may include exposure to exposure to chemicals or sun, or whether or not your female pet is spayed.

Most cancers are caused by a combination of both genetic and environmental factors. And, as a pet owner, it is important to note that there is likely nothing you did or did not do to cause your Great Dane’s cancer.

Common Types of Great Dane Cancer


Lymphoma is a blood-borne cancer, where there are mutations of a type of white blood cell. Unusual swelling or growths are indicators of this type of cancer.

These growths are usually found near the dog’s lymph nodes—under the chin, in the groin area, or in the leg or armpit areas.

Thankfully, this type of cancer is largely treatable, as long as it is detected early. Also, the swelling is fairly painful for your Great Dane.

Mast Cell Tumors

Mast Cell Tumors, another type of blood cancer, are abnormal growths on your dog’s skin or internal organs. More commonly found on the skin, this type of cancer is usually easy to visually detect.

A veterinarian will be able to determine if these tumors are either low-grade or high-grade. Low-grade tumors can easily be removed with surgery. High-grade tumors may need surgery and an additional form of treatment, like chemotherapy.


Osteosarcoma is a type of bone cancer commonly impacting larger breeds. A more aggressive disease, osteosarcoma quickly spreads and can be extremely painful for your Great Dane.

Unfortunately, it is also difficult to visually detect. Be on the lookout for swelling or tenderness—especially on their legs—or joint pain.

Your veterinarian will need to take X-rays to confirm the diagnosis, but treatment can include amputation and/or chemotherapy. This is one of the most common types of cancers impacting Great Danes.


Similar to Mast Cell Tumors, lipomas are skin tumors composed of fatty tissue. Thankfully, lipomas are generally benign, or non-cancerous. While generally not dangerous, they can impact your pet’s ability to move, sit or lie down comfortably.

Lipoma’s should still be treated surgically. Lipomas can develop internally. Unfortunately, these types of lipomas can sometimes push on internal organs.

They may be dangerous or uncomfortable for your Great Dance. Surgery is more difficult but is still likely the best option for treatment.

Oral Melanoma

Oral melanoma is a type of oral cancer, meaning it impacts the mouth and surrounding areas. This type of cancer is common in dogs with darker-colored mouths.

These tumors start in the mouth or surrounding areas. However, they can spread to the throat, jawbones and, eventually, to the lungs or other parts of the head.

Signs of oral melanoma include difficulty swallowing or breathing, have bleeding or other discharge coming from their mouth, or swelling in by their lymph nodes.

Anal Glad Adenocarcinoma

This type of cancer impacts your Great Dane’s anal gland. While rather rare, it is an aggressive disease. It is often difficult to treat.

Anal glad adenocarcinoma typically appears as a tumor. However, it can be difficult to visually detect tumors in this area.

Other symptoms including difficulty defecating or lethargy. Surgery and radiation are the usual courses of treatment.

Mammary Gland Carcinoma

Mammary gland carcinoma is more common in female dogs. This type of cancer impacts your pet’s mammary glands. These glands help in the milk production process for mothers.

Half of all cases of mammary gland carcinoma are malignant, or dangerous, and half are benign.

The most common symptom of this type of cancer is unusual swelling or growth. Surgery is the typical course of treatment.

Primary Lung Tumor

Primary lung tumors are tumors found on the lungs. They can negatively impact your Great Dane’s respiratory system. Unfortunately, almost 80% of primary lung tumors are malignant and may spread to other respiratory organs.

If your pet is starting to experience difficulty breathing, that may be a symptom of this type of cancer. Surgery, followed by chemotherapy or radiation, is typically used to treat these tumors.

Thyroid Carcinoma

Thyroid carcinoma results in tumors developing on your dog’s thyroid gland. This gland is located in the throat. It is essential for managing weight and hormones throughout the body.

Symptoms include swelling or growth in the throat area, difficulty eating or breathing, and dramatic weight fluctuation.

Unfortunately, there is no cure or common treatment for this type of cancer. Surgery may be used to help alleviate some of the issues and remove part of the tumor.

However, this will not eliminate the cancer entirely.


Hemangiosarcoma happens when tumors develop in your dog’s blood vessels. Because it starts in blood vessels, this type of cancer easily spreads to other organs and parts of the body.

Hemangiosarcoma is commonly found in dogs—and not nearly as often in humans or other species.

This type of cancer impacts internal organs. Unfortunately, there are rarely visual symptoms. Look out for weakness, a change in energy level or a change in engagement level.

Surgery, radiation, and chemotherapy are often used as treatment methods.

Treatment Options for Great Dane Cancer

While Great Dane cancer can be scary, there are different options for cancer treatment.

Your veterinarian may recommend a specific course of treatment, depending on your Great Dane’s type of cancer, how aggressive the disease is, and how old or generally healthy your pet is at the time of diagnosis.

Every treatment is different. Every Great Dane reacts differently. You and your veterinarian will just need to make an informed decision to ensure a high-quality of life for your dog.


Surgery is common for cancers that produce tumors or unusual growths. For benign growths, this is commonly the easiest way to extract the mass.

For malignant growths, surgery may only be the first step in treatment and recovery.

Depending on the type and location of the tumor, your veterinarian may use a general or local anesthetic. This is followed by physically cutting away the unusual mass.


Chemotherapy, commonly called chemo, involves giving your dog a mixture of drugs meant to kill mutated cells and prevent further mutations.

Side effects of chemotherapy include gastrointestinal issues, hair loss, lethargy, and skin irritation. Generally speaking, dogs tend to deal with chemotherapy more easily than humans do.


Radiation is not a cure for cancer. It is palliative care, meaning it is meant to decrease pain for your pet. It also helps to prevent the continued growth of tumors.

Radiation treatment uses high-energy radiation to target and break down cancerous cells. Unfortunately, it is sometimes difficult to ensure just the cancerous cells will be impacted.

Every time your Great Dane gets radiation, a general anesthetic may be used.

Side effects of radiation included skin irritation, loss of appetite, diarrhea, and nausea.


Immunotherapy involves stimulating your pet’s own immune system to help fight against cancer. This can be done with a group of drugs that are given orally or through injections/shots.

Immunotherapy is frequently used to help dogs with severe allergy issues.

This type of treatment would likely be used in conjunction with another course of treatment—and would not be used alone.

Conclusion on Great Dane Cancer

Ultimately, cancer sucks…  There is no nice way to say it.

Should you see any of these mentioned symptoms, have your veterinarian check your Great Dane immediately. Early detection gives your beloved furry friend the best chance at survival.

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