Dog Cancer – Symptoms, Diagnosis & Treatment

Dog Cancer

Here’s a detailed description based on the provided text, along with key takeaways about dog cancer.

Understanding Canine Cancer

Cancer remains a serious threat for our beloved canine companions. Unfortunately, detection can be difficult, and treatment is often initiated too late. Being aware of warning signs is crucial for early diagnosis and successful intervention.

Common Cancer Types in Dogs

  • Liver Cancer: Impacts the vital organ responsible for detoxification.
  • Bone Cancer: Affects the skeletal system, causing pain and potential fractures.
  • Skin Cancer: Can manifest as various skin lesions or tumors.
  • Lymphoma: Targets the lymphatic system, a key part of the immune response.
  • Mammary Tumors: Develop in the breast tissue of female dogs.
  • Testicular Tumors: Affect the reproductive organs in male dogs.

Causes of Canine Cancer

  • Genetics: Certain breeds are predisposed to developing tumors.
  • Environment: Exposure to toxins or carcinogens can increase risk.
  • Aging: The risk generally increases as dogs get older.

Warning Signs of Cancer in Dogs

  • Behavioral Changes: Unusual withdrawal, lethargy, or disinterest in play.
  • Gastrointestinal Issues: Persistent vomiting and diarrhea.
  • Unexplained Weight Loss and Lack of Appetite: Can signal caloric competition between healthy and cancerous cells.
  • Fatigue and Weakness: Cancer can strain the body’s resources.
  • Breathing Difficulties and Persistent Cough: Possible indicators of lung tumors.
  • Lumps or Swelling: Any unusual masses under the skin warrant examination.
  • Skin Lesions: Sores or wounds that don’t heal properly.
  • Other Potential Signs: Seizures, pale gums, bad breath, lameness or limping.

Importance of Veterinary Consultation

Remember, these symptoms may overlap with less severe conditions. However, if you notice any of these changes in your dog, immediate veterinary consultation is essential. Early diagnosis dramatically increases the chances of successful treatment.

Diagnosis Process

  • Veterinary Examination: The first step to assess your dog’s health.
  • Additional Tests: Biopsies, X-rays, ultrasounds, blood work, or CT scans may be necessary for a definitive diagnosis.
  • Staging: Determines the extent of the cancer and if it has spread.

Treatment Options

  • Surgery: May be used to remove localized tumors.
  • Chemotherapy: Drugs administered to target and destroy cancer cells.
  • Radiation Therapy: Specialized treatment to shrink or eliminate tumors.
  • Combination Therapy: May be recommended in some cases.

Key Takeaways

  • Vigilance is Key: Pay close attention to any changes in your dog’s health or behavior.
  • Early Detection Saves Lives: Don’t delay veterinary visits if you suspect something is wrong.
  • Cancer is Treatable: With prompt diagnosis and appropriate treatment, many dogs can enjoy extended quality of life.
  • Consult Your Veterinarian: They are your best resource for information and guidance on canine cancer.

Remember: While cancer is a scary diagnosis, knowledge is power. By being informed and proactive, you can be your dog’s best advocate in their health journey.

Types Of Common Cancers in Dogs:

Different types of cancers, more or less serious, can affect dogs. It is of course essential to diagnose the tumor as quickly as possible to implement rapid and appropriate treatment.

As in humans, cancer cells can appear anywhere in a dog’s body. In the worst cases, the cancer is widespread when metastases develop throughout the animal’s body.

Among the most common canine cancers, we can cite:

  • Liver cancer;
  • Bone cancer;
  • Skin cancer ;
  • Lymphoma (cancer of the lymphatic system);
  • Breast tumors;
  • Testicular tumors;

The severity of cancer in dogs depends in part on the area affected by the primary tumor, but also on the evolution of the cancer cells.

Cancer results from mutations or genetic abnormalities appearing at a certain stage of life, transforming an organism’s healthy cells into tumor cells. These tumor cells can be located in a well-defined mass called a tumor or can circulate throughout the body when the cancer affects the blood system or the lymphatic system.

There are different forms of cancer depending on the organs affected and the severity of the cancer.

We speak of metastatic cancer or cancer with metastases when the cancer has spread to several organs. The presence of metastases is a criterion for the severity of a cancer.

A cancer is considered benign when it tends to grow slowly and when it generates no or few metastases.

A cancer is classified as malignant when it tends to grow rapidly and when it leads to the appearance of metastases to other organs.

The most common cancer in dogs is lymphoma; It is a cancer that affects the lymphatic system. But it is also the cancer best known to practitioners and researchers and for which chemotherapy protocols exist and can work.

Causes Of Cancer In Dogs:

Just like in humans, there is no single symptom that can indicate cancer. The first signs are sometimes almost imperceptible, which is why the possible symptoms must be well understood. In addition to the fact that dogs over 10 years old have a higher risk, veterinary medicine has determined that if detected early, 50% of cancers can be treated.

It is difficult to prevent the onset of canine cancer, especially in older pets. Given the large number of tumors that a dog can suffer from, the origin of cancers is also very varied.

It is therefore considered that there are three main causes for the appearance of cancer in dogs:

Genetic Material:

Some dogs are unfortunately predisposed to developing cancers. It is a disorder that is frequently found in purebred dogs subject to excessive inbreeding.

The Environment:

Like humans, dogs are exposed to their environment. The dog’s lifestyle, its diet, or even its immediate surroundings can increase the risk of the appearance of cancer.


Finally, we must not neglect the impact of aging. If cancer is becoming one of the most common causes of death in domestic animals, it is because veterinary medicine is becoming more and more effective in the treatment of infectious diseases or accidents.

Symptoms of Cancer In Dogs:

Older dogs are most predisposed to cancer. Specific breeds also develop more tumors than others. For example, the Boxer is particularly predisposed to cancer, particularly mastocytoma (skin tumor affecting cells called mast cells).  The symptoms that appear depend on the type of cancer. The most common are:

A Change In Behavior:

Manifested by your dog becoming unusually withdrawn and unresponsive to activities that previously interested him, such as playing or petting. These signs may indicate that he is suffering morally or physically. A visit to the veterinarian will be the best way to find out for sure.

Vomiting and Diarrhea:

Vomiting and diarrhea can be a sign of parvovirus, diabetes, poisoning, or the consequence of too much food. However, they can also be a sign of stomach or intestinal cancer. If they persist and are not very far apart, take your dog to a veterinarian immediately.

Loss of Energy and Feeling Tired:

Cancer tires your pet’s body. It is therefore not uncommon for a dog suffering from a malignant tumor to be more tired, less playful or even less inclined to go for walks. He most often appears apathetic and inactive, even if you try to stimulate him to go out or play. Obviously, fatigue is not just a sign of cancer, but it is not a normal state for a dog; It is therefore best to consult a veterinarian quickly.

Weight Loss and Loss of Appetite:

If you haven’t changed your dog’s eating habits, but he is losing weight or has no appetite, you need to be concerned. These disorders do not necessarily mean cancer, as they are generally common to many diseases and disorders. It can also be temporary stress or even depression. However, if this persists, consult your veterinarian without delay.

Cancer causes weight loss because healthy cells in the canine body are in conflict with cancer cells, resulting in greater calorie consumption. In addition, a tumor located in the mouth or digestive system can cause pain in your dog when eating, which tends to reduce its appetite.


If your dog sleeps longer than his usual sleeping pattern, if he expresses abnormal laziness accompanied by fatigue at the slightest physical effort and by unusual and sudden weakness, seek help from a veterinarian. Cancer can infect the nervous system and muscles.

Cough and Breathing Difficulties:

Cough or breathing difficulties can be due to old age (for example, physical exertion is likely to cause breathing difficulties in older dogs) or bronchitis. However, they can be a sign of lung cancer. If these symptoms are repetitive and persist, do not hesitate to take your dog to a veterinarian.


If your dog is having seizures, it is important to act quickly and consult a veterinarian urgently. Of course, it could be a tumor affecting his brain or nervous system, but it could also be something else. However, take action, because seizures should not be taken lightly. In addition, the practitioner will be able to advise you on how to act in the event of a crisis.

Respiratory Problems and Cough:

Coughing does not come naturally to dogs, so it should be taken seriously. Your dog may suffer from respiratory problems that tend to trigger this dry cough. The dog may wheeze and struggle, such as after intense exercise. Consult your veterinarian quickly, especially if you notice that his cough is accompanied by bloody secretions.


Knowing that a dog’s normal temperature is between 37.7 and 38.8°C. The temperature is measured rectally, using a thermometer.

Pale Gums:

The dog’s gums should have a pink color. It is an indicator of good oxygenation and blood circulation. Pale gums are a sign of a lack of blood flow and may be linked to a serious illness.

Bad Breath:

Dogs often have bad breath, that’s a fact. However, if you notice foul, strong odors that persist in his mouth, nose, ears, or rectum, it may be a more serious problem. Obviously, this can only be due to a wound that heals poorly or difficult digestion, but cancer cannot be ruled out. We advise you to consult the veterinarian quickly.

A Limp:

Pain, whether due to a cancerous tumor or an injury, can greatly weaken your pet. Your dog will tend to refuse outings and games or force himself to do so for your pleasure while showing discomfort. If he limps or appears to be in pain, be alarmed, because your dog may be injured or affected by bone cancer. In general, consult your veterinarian without delay, because an injury, even a minor one, can get worse if not treated properly.


If you notice bumps or lumps forming on your pet, they may be cancerous tumors. It is then advisable to consult your veterinarian to identify the reason for this bulge. However, these lumps can have other origins, which is why there is no need to panic. In fact, they can simply be warts or small cysts, or even benign tumors, therefore non-cancerous.

Cuddling, scratching, and brushing times are ideal for monitoring your pet’s body and possibly detecting these lumps.

You may also notice swelling in the lymph nodes located in the dog’s neck and behind the knees, in the joint crease. It may then be lymphoma, a cancer of the lymph nodes. In this case, go to the veterinarian without delay.

Skin Problems:

Your pet can get sores, injuries, or small skin lesions when playing outside. When properly cared for, they heal smoothly over time and are nothing to worry about. On the other hand, if you notice that these skin marks do not disappear, that they do not heal well, or that your dog suffers from frequent itching, it may be skin cancer.

Also, observe the color of your pet’s gums. When it is healthy, they are pink/red in color. On the other hand, if you notice that they are changing color, especially if they take on a paler shade, it could be a cancer that is disrupting blood circulation or at least a serious condition.

What To Do If You Suspect Cancer?

The disorders mentioned above are common to other pathologies and may not be a sign of cancer. However, we recommend that you consult your veterinarian quickly when they appear. If it is cancer, your pet’s chances of survival are greatly linked to how early the diagnosis is made; The earlier the cancer is detected, the sooner the appropriate treatment can be implemented and the better the chances of remission.

If it is not cancer, the veterinarian will be able to identify the cause of these symptoms, and then treat another significant disease. So don’t wait to take care of your doggie.

Diagnosing Cancer In Dogs:

If your dog appears to be in poor health, you have detected a cyst, or is suffering from any of the symptoms mentioned above, it is important to consult a veterinarian as soon as possible. Only a dog health specialist can diagnose cancer.

To date, no veterinarian can say with certainty the seriousness of such a condition in a dog without first carrying out extensive examinations (cytology, biopsy, etc.).

The veterinarian must first establish a diagnosis by carrying out additional examinations. These examinations depend on the type of cancer suspected based on the symptoms observed. This may involve, for example, biopsies (taking a piece of the tumor to determine its nature), an abdominal ultrasound, a bone marrow aspiration, or even a CT scan.

A follow-up assessment helps clarify the progression of the disease. When cancer is diagnosed, it is essential to understand its progression. In particular, it is important to know whether the disease has spread to other organs.

The diagnosis of cancer in dogs can be started after an initial examination of the animal. To be confirmed, it is often necessary to complete it with an x-ray or tests, such as a biopsy.

Once the diagnosis has been made, the veterinarian will offer an extension assessment. The purpose of this assessment is to know whether or not the identified cancer is associated with the presence of metastases.

Treatment Of Cancer in Dogs:

There are three types of treatment for cancer in dogs; surgery, chemotherapy, and radiotherapy.

If the cancer appears in the form of a tumor that affects only one organ, surgery may be considered with the aim of completely removing the tumor. This is the case, for example, of hemangioma of the spleen for which the veterinarian will suggest splenectomy (removal of the spleen).

For more “diffuse” cancers, such as lymphoma or leukemia, a chemotherapy protocol is generally recommended. In dogs, chemotherapy consists, as in humans, of the administration of anticancer drugs, orally or intravenously. This may require the hospitalization of your pet. Anticancer drugs destroy cancer cells. The side effects of chemotherapy in dogs are generally less severe than in humans.

Finally, radiotherapy can be offered to destroy or attenuate certain cancers using radiation which blocks the multiplication of cancer cells. Veterinary radiotherapy can only be done in very specialized centers. Sometimes, several types of treatment can be combined to treat cancer in dogs.


Cancer in dogs is characterized by the appearance of one or more malignant tumors due to the transformation of healthy cells, due to genetic abnormalities or mutations.

Cancerous tumors in dogs are then likely to multiply and a primary tumor can spread throughout the body and give rise to other tumor cells called metastases. As they grow, tumors can reach vital organs, or even the animal’s blood system, and cause significant physical deterioration, then death.

Aapt Dubey
Aapt Dubey

Aapt Dubey, a devoted canine enthusiast and experienced dog Owner, brings boundless passion to our team. With a heart full of love for our four-legged friends, Aapt is dedicated to sharing insights on dog care, behavior, and training to make every pup's life happier and healthier at

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