Comprehensive Guide to Dog Cancer: Early Signs and Vet-Verified Treatments
Cancer in dogs is often a heartbreaking diagnosis, being one of the leading causes of death in this species. In fact, this disease can affect 1 in 4 dogs at some point in their lives.
For many owners, the word “cancer” carries a heavy emotional weight. It can be overwhelming and emotionally devastating. However, with today’s treatment options, dogs can have an extended life span after such a diagnosis, especially when a timely diagnosis is made. In other words, a cancer diagnosis does not always mean an immediate death sentence.
This guide aims to give you an overview of cancer in dogs and help you recognize the early signs, understand treatment options, and make informed decisions during a difficult time for both you and your beloved pet.
What Is Cancer in Dogs?
Cancer is the abnormal, uncontrolled growth of cells in various organs and tissues. This sneaky disease can develop anywhere in a dog’s body.
The causes of cancer are unknown, but several risk factors make dogs more susceptible, such as:
Age – Cancer generally occurs in older dogs (median age is 8.8 years). One of the hypotheses for why age is a factor in the development of cancer is that in older animals, the immune system declines and no longer has the same ability to control the abnormal cells that could become malignant. However, male dogs can also be diagnosed at a younger age than females.
Sex – Some types of cancer are more common in males (e.g., osteosarcoma), and others in females (e.g., mammary carcinoma).
Direct transmission of tumor cells – One of the genital cancers in dogs can be sexually transmitted. It is called canine transmissible venereal tumor (CTVT) or Sticker's sarcoma. An infected dog can transfer cancer cells to a healthy dog during sex. CTVT spreads through direct contact with infected tumor tissue.
Breed – Some breeds of dogs are more prone to developing cancer, such as Boston terriers, Boxers, Great Danes, Irish Setters, Poodles, Golden retrievers, Labrador retrievers, etc.
Environmental factors – Pesticides, herbicides, insecticides, ultraviolet radiation from long exposure to the sun, secondhand smoke, air pollution, and smog can trigger the development of cancer in dogs.
Lifestyle – Lack of physical activity and sedentarism can lead to obesity. As a result, overweight dogs have a higher risk of several diseases, including certain types of cancer.
Diet – A nutritionally unbalanced diet can weaken a pet’s immune system, increasing their susceptibility to infections, chronic inflammation, or other conditions that can contribute to an increased risk of developing cancer. Additionally, diets high in poor-quality protein, fillers, preservatives, or chemical additives are associated with long-term health problems and the development of cancer.
Why Is Cancer in Dogs Becoming More Common?
Cancer in dogs seems to be on the rise - it is like you hear about more and more cases of cancer. In addition to the risk factors we outlined earlier (environmental factors, lifestyle, and diet), cancer also seems to be more common because it is now being diagnosed more often. This is because dogs now have longer lifespans, which gives cancer time to develop. In addition, advances in veterinary medicine have led to the development of tools that allow specialists to diagnose cancer in dogs earlier. Pet owners are also becoming more aware, are more informed, and proactive about cancer, which leads to more visits to the vet and, ultimately, cancer diagnosis.
Why Cancer Early Detection is Important?
Early detection of cancer in dogs is important because it can significantly improve your pet's survival rate and quality of life. In the early stages, cancer is easier to locate and treat than in the late (terminal) stages, where the cancer has spread throughout the body and treatment of the disease is most often no longer an option. As a result, early diagnosis of cancer in dogs increases the chances of successful treatment (surgery, chemotherapy, radiotherapy, or a combination of these). In addition, early detection of cancer in dogs allows for less aggressive treatment, which can reduce side effects and improve the comfort of the affected pet.
For owners, early diagnosis can also provide more time to make informed decisions and plan the best course of care for their dogs. Simply put, the sooner cancer is detected, the more effective its management can be.
Common Types of Dog Cancer
As mentioned earlier, cancer can occur anywhere in a dog’s body. However, some types of cancer in dogs are more common, such as:
1. Lymphoma/Lymphosarcoma
Lymphoma in dogs leads to the enlargement of the lymph nodes in the body, small pieces of tissue that are part of the lymphatic system and have an important role in the immune system. It is one of the most common types of cancer seen in dogs and veterinary practice. It is characterized by a malignant proliferation of lymphoreticular cells that normally come from the lymphoid tissues (lymph nodes, spleen, bone marrow).
Lymphoma can occur in almost any part of the body. It generally occurs in dogs between the ages of 6 and 9, and the most affected breeds include Boxer, Golden Retriever, Scottish Terrier, Rottweiler, Akita, Siberian Husky, Malamute, and Shih-Tzu.
Canine lymphoma has several forms, the most common being multicentric lymphoma (80-85% of cases). This is characterized by the enlargement of the peripheral lymph nodes (those that can be palpated). Regarding the clinical signs of multicentric lymphoma, many dogs do not show clinical signs. However, lethargy, anorexia, vomiting, weight loss, and respiratory difficulties can be observed in some cases.
The gastrointestinal form is the second most common form of lymphoma, affecting the stomach and intestines. Clinical signs can include vomiting, diarrhea, and weight loss.
Mediastinal lymphoma affects the lymphoid structures in the thoracic cavity and causes respiratory problems due to the tumor mass or fluid accumulated in the cavity.
Extranodal forms are rarer and affect non-lymphatic organs:
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Cutaneous lymphoma (most often of T-cell origin) causes extensive ulcerated lesions, difficult to treat. It is the most common form of extranodal lymphoma.
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Renal lymphoma is aggressive, with nonspecific symptoms (anorexia, vomiting, hematuria) and changes in blood tests and imaging.
- The nasal form can cause facial deformity, nosebleeds, and discharge.
- The ocular form includes inflammation (uveitis) and blood accumulation in the eye ( hyphema).
Treatment for lymphoma in dogs involves the administration of several chemotherapy drugs. However, this condition can rarely be cured. The majority of affected and treated pets will experience a recurrence of the cancer at some point in their lives. However, a second remission is sometimes possible with additional therapy.
2. Mast Cell Tumors (MCT)
MCT is one of the most common skin tumors in dogs. These tumors can occur on or under the skin and, occasionally, within the abdomen or chest. In dogs, most forms of mast cell tumors (85%) are benign, not spreading at a distance. They are only locally infiltrative. The remaining 20% may suffer from aggressive forms of MCT, which can spread to other organs and tissues (metastasize) – the most common organs and tissues to which MCT spreads are the lymph nodes, liver, and spleen.
All breeds can develop MCT, but Bulldogs, Pugs, American Staffordshire, Weimaraner, and Labradors have a higher prevalence. It is more common in males.
Clinical signs most often include an abnormal growth on or under the skin, which can have different appearances and colors, such as a whitish or reddish nodule, similar to a cyst or benign skin tumor (papilloma or lipoma). Because of this, MCT can often be confused with other skin conditions. Pain is not common with MCT, but it can occur if the dog constantly scratches or bites the tumor. MCT rarely ulcerates or forms abscesses in its early stages.
Treatment mainly consists of surgical removal of the tumor, when possible. If the tumor cannot be removed surgically, radiation therapy and chemotherapy may be recommended. Dogs without metastases have a longer survival time.
3. Osteosarcoma (Bone Cancer)
Osteosarcoma is one of the most common types of cancer in dogs. It usually develops in middle-aged or older dogs. However, it can also occur in dogs as young as 2-3 years old. Like other types of cancer, osteosarcoma has a breed predisposition, occurring more frequently in large dog breeds such as Bernese Mountain Dog, Great Dane, Newfoundland, Cane Corso, and others. It is also more common in males than in females.
It usually occurs in one of the limbs, being an aggressive cancer that spreads quickly to other organs, such as the lungs.
Clinical signs include lameness and inflammation of the tissue where the bone cancer occurs. Treatment consists of amputation of the affected limb, followed by chemotherapy. To avoid amputation, radiotherapy may be recommended. The average survival time depends on the treatment of the disease and the stage of the cancer. As a result, dogs can have an average life expectancy of 6 months if radiotherapy and chemotherapy are chosen; those that undergo amputation and chemotherapy have a survival time of up to a year. If dogs are left untreated, their life expectancy is approximately 3 months from diagnosis.
4. Hemangiosarcoma (HSA)
Hemangiosarcoma is one of the most aggressive types of cancer in dogs that can spread very quickly throughout the body to organs such as the liver and lungs. HSA develops from blood vessels and can occur anywhere in the body. However, HSA most often affects a dog's spleen, heart, liver, or skin.
HSA is most commonly diagnosed in middle-aged and senior dogs. Although it can develop in any breed, some dogs are more prone (German Shepherd, Golden Retriever, Labrador Retriever, Boxer, Pit Bull, Whippet, Greyhound, Greyhound, Beagle, Basset Hound).
Clinical signs of visceral HSA (in the internal organs) may include acute weakness, collapse, lethargy, loss of appetite, weight loss, abdominal distension and pain, pale (anemia) or yellow (jaundice) mucous membranes, and increased respiratory rate.
Surgery to remove the tumor is vital because the tumor can rupture and cause abdominal bleeding, and the dog may die. If the tumor has spread to the spleen, your veterinarian will recommend removing it (splenectomy). The average survival time is only a few months for visceral hemangiosarcoma. For cutaneous HSA, the survival time can be up to 2 years, depending on the stage of the cancer and the dog's general health.
5. Malignant Melanoma
Melanoma in dogs is a common form of skin cancer. However, it can also occur in the oral cavity, eyes, or meninges. This cancer arises from melanocytes, the cells responsible for producing pigment in the skin, eyes, nails, and fur. It generally occurs in older dogs, and breeds such as Boston Terriers, Doberman Pinschers, Golden Retrievers, Papillons, and Chihuahuas are more prone to it.
The tumors are usually large, raised (bumps) or flat, with most owners seeing them as a black spot. Other clinical signs include bleeding at the site, difficulty eating, and difficulty breathing.
Treatment of melanoma in dogs may include surgery, radiation therapy, chemotherapy, and immunotherapy, depending on the location.
Malignant melanoma has a poor prognosis because it can spread to the lungs.
6. Transitional Cell Carcinoma (TCC) of the Bladder
Transitional cell carcinoma is the most common bladder cancer in dogs (75% of cases). It arises from the transitional epithelial cells that line the inner surface of the urinary bladder. TCC is locally invasive but can also spread to other tissues and organs in the body. It can occur in all dog breeds, but some are more prone, such as Beagles, Fox Terriers, Scottish Terriers, and West Highland White Terriers. The average age of onset is over 7 years.
Clinical signs of TCC may include frequent urination (sometimes bloody), straining to urinate, accidents in the house, lethargy, decreased appetite, and weight loss. In advanced cases, dogs may even develop urinary blockage.
Treatment largely includes chemotherapy and nonsteroidal anti-inflammatory drugs (NSAIDs). Surgical removal is often difficult to perform due to the location of the tumor. Radiation therapy can also be recommended. The average survival time in untreated dogs is only a few months, while those who receive treatment can have an average life expectancy of 6-12 months.
Symptoms And Early Warning Signs Of Cancer In Dogs
Recognizing the early signs can help diagnose cancer early and, consequently, extend your dog's life expectancy. Keep in mind that clinical signs can vary depending on the type and location of the cancer. However, some warning signs should be considered.
Physical Changes to Watch for
Check your pet's skin, mouth, eyes, paws, and nails often. Look for lumps on or under their skin, swellings, and dark spots. Monitor for changes in shape, growth (tumors tend to grow fast), or don’t go away. There may also be wounds that don't seem to heal; these could be signs of cancer.
Here are some other clinical signs you may notice that may be red flags:
- Weight loss (often sudden)
- A distended and/or painful abdomen
- Unexplained bleeding (mouth, nose)
- Blood in urine and stool
- Chronic vomiting (sometimes bloody)
- Limping
- Difficult breathing
Changes in behavior and appetite
Cancer in dogs can cause subtle but significant behavioral changes. Your dog may seem to have less energy than usual, will not play as much as before, will seem more tired, and may sleep more often. You may also notice a sudden decrease in appetite or changes in their drinking habits. Some dogs may hide more, show signs of discomfort or pain, or become unusually clingy or irritable (aggressive).
When to seek veterinary help
If any of these signs persist for more than a few days or if your dog appears to be in pain or is unusually lethargic, it is important to contact your veterinarian as soon as possible. These signs indicate that your dog has a health problem and, even if it is not cancer, will require veterinary attention. Early diagnosis of any health problem (including cancer) can lead to more appropriate treatment options and a better prognosis.
Diagnosing Cancer In Dogs
Diagnosing cancer in dogs is a multi-step process that begins with a physical exam and medical history. If your dog has unusual lumps on their skin, has lost weight suddenly, has changed their appetite, or has changed their behavior, these could be early warning signs of cancer. If your vet finds a lump (on their skin or inside their body), they may recommend a fine needle aspiration (FNA) to see if cancer is present – the vet examines the cells collected under a microscope (it is called a cytology exam). In cases where the FNA result is inconclusive, the vet may recommend repeating the FNA or a biopsy (surgical removal of the tumor and examination under a microscope – it is called histopathological examination).
Keep in mind that the histopathology exam is the exam that leads to a definitive diagnosis and identifies the type of cancer. In addition, your vet may recommend blood tests, urine tests, or imaging exams, such as X-rays and ultrasounds, to see if the cancer has spread throughout the body. For more detailed information, especially in the case of complex or internal cancers, advanced imaging such as CT scans or MRIs can be used – these are also recommended before surgery to get a better view of the location and size of the tumor.
The type, grade, and stage of the cancer are crucial information that your veterinarian needs to know in order to develop a treatment plan tailored to your dog’s cancer and overall health.
Early and accurate diagnosis not only improves the success of treatment but also gives you the time and clarity needed to make the best decisions for your dog’s care and quality of life.
Treating Cancer In Dogs
Cancer treatment in dogs depends on several factors, such as the type, location, and stage of the disease, but also on the general health of your dog. Most of the time, your veterinarian will recommend a veterinary oncologist who will prescribe and carry out the treatment for your dog.
When it comes to cancer, the goal is not always to cure the disease because this is often not possible. Instead, the treatment usually focuses on slowing the progression of the cancer and improving the dog's quality of life.
The most common cancer treatment options in dogs include:
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Surgery - is often the most preferred method of treatment, especially when the cancer has not metastasized.
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Chemotherapy - is recommended after surgical excision, in the case of metastases, or when the cancer cannot be treated surgically. This is generally well tolerated by dogs (unlike humans), with side effects not being as pronounced.
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Radiation therapy – this may be recommended to shrink tumors, relieve pain, in combination with other treatment methods, or when surgical removal is not possible.
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Palliative care – palliative treatment aims to improve quality of life. As a result, the vet may recommend pain medications, anti-inflammatories, supplements, and nutritional support.
A complete remission occurs in rare cases. However, cancer treatments help extend your pet’s life. Your vet will help you evaluate the benefits, risks, and costs of treatment to make the best choice.
Alternative Therapies
Alternative therapies, while not a cure for cancer, can help boost your dog's immune system, making them stronger against the disease. So, if your dog has cancer, here's what you can try:
Zumalka’s SHIITAKE supplement is formulated to support a healthy immune system and liver function. Shiitake mushrooms are rich in essential nutrients like vitamins B2 and B12, which may help enhance your dog’s energy, reinforce their natural defenses, and protect against environmental stressors, helping them stay strong and feel their best every day. This supplement is great for dogs with stomach, colorectal, pancreatic, and liver cancers. Studies on humans showed that Shiitake supplements extended their survival time.
Zumalka’s Reishi supplement is a capsule that contains reishi mushroom. Its antioxidant-rich formula is designed to support dogs with severe conditions like cancer. Reishi mushrooms were traditionally used to strengthen the immune system and promote healthy cell function. They are also known for supporting liver health and enhancing the body’s natural defense mechanisms, especially during harsh treatments like chemotherapy. Research in humans suggests that the Reishi mushroom may help inhibit protein synthesis and slow tumor growth.
Zumalka’s Coriolus (Turkey Tail) product is a powerful natural supplement that is packed with polysaccharide-K (PSK) that promotes a healthy gut microbiome, boosts the immune system, and supports recovery.
Zumalka’s HEPATOPET product is an excellent liver tonic with immune-boosting and anti-inflammatory benefits for your dog. It contains astragalus, milk thistle, and curcumin, which can support your dog’s liver, especially when they are on chemotherapy medication.
Zumalka’s product PIPTOPET, a mother tincture that contains Fomitopsis betulina, can be administered to support your dog’s immune system and body. To support your dog’s overall vitality and wellness, PIPTOPET can be used alongside TONICPET #4, #5, #7, and #10, which are formulated to help maintain immune function, oxygenation, circulation, and internal balance.
By combining Zumalka’s products, you can provide your dog with a powerful, natural kit to boost their immune system and overall health.
Always consult a holistic vet or pet homeopathy specialist before using any natural remedies or products.
Preventing Cancer In Dogs
Unfortunately, cancer in dogs cannot always be prevented, but you can take certain preventive measures to reduce the risks, such as:
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Spaying or neutering – Studies show that neutering your dog decreases the chances of them developing mammary and reproductive system tumors.
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Weight management – Obese pets are more likely to develop cancer. As a result, ensuring a healthy diet and keeping your dog active can reduce the risk of developing cancer.
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Limiting exposure to toxins – Reduce your dog’s exposure to pesticides, insecticides, cigarette smoke, and other environmental pollutants as much as possible.
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Limiting sun exposure – Reduce your dog’s exposure to UV rays, especially if you have a light-colored dog, to lower the risk of skin cancer.
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Regular veterinary check-ups – It is important to take your dog for regular medical check-ups to catch any health problems in a timely manner.
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Genetic awareness – It is important to remember that some breeds are more prone to cancer.
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Administering supplements - PIPTOPET is a great option for prevention by boosting the immune system and targeting unhealthy cells in the body.
Managing Treatment and Side Effects
Conventional treatments like surgery, radiation therapy, and chemotherapy often come with side effects. While many dogs tolerate these side effects well (especially those caused by chemotherapy), some patients may present with lethargy, loss of appetite, fatigue, pain, skin redness (in the case of radiation therapy), and/or gastrointestinal upset. For these side effects, your veterinarian may recommend pain medications, antiemetics, appetite stimulants, and nutritional support. The medication and medical management can significantly improve your dog's quality of life. Therefore, it is advisable to work closely with your veterinarian to provide your dog with the care they need.
The Emotional Impact of Cancer in Dogs on Pet Owners
A cancer diagnosis can be emotionally overwhelming. For many pet owners, the diagnosis can be stressful and have a significant impact on their mental well-being as well. The stress of making a decision, managing costs, making changes to their home environment, and caring for their pet during this difficult time in their life can be overwhelming. However, if you rely on support and focus on your pet's comfort, you can make it through this difficult journey.
End-of-Life and Palliative Care in Dogs With Cancer
When your dog is diagnosed with terminal cancer, palliative care and improving the quality of life are essential. As a result, as previously mentioned, palliative care can relieve pain and clinical signs, improving your pet's final moments. It is essential that during this critical period, you monitor your dog's condition to see if it is getting better or worse. Here are some signs that may tell you that your dog's condition is getting worse:
- Difficult breathing
- Reduced appetite or no appetite (the dog refuses to eat)
- Visible pain and discomfort
At these times, your veterinarian can guide you on when to make the heartbreaking decision to humanely euthanize your dog. This decision is not easy and can have an impact on you, but it is an act of love and compassion for your suffering dog. Surround your dog with love and make them feel as comfortable as possible in their final moments.
Above all, the goal at this stage is to ensure that your pet feels safe, cared for, and loved until the end of their journey, whether you choose to end their suffering or let them pass naturally.
Financial Considerations
The cost of cancer in dogs depends mainly on the type of cancer and the treatment options. If your veterinarian recommends chemotherapy, the cost per session can range from $100 to $500 (depending on the size of the dog and medication).
The cost of surgical treatment will be determined depending on the location of the tumor and the complexity of the procedure (for example, a surgery to remove a tumor in the stomach will be much more expensive than one on the skin). Therefore, it can reach up to $7,000.
If you choose radiotherapy, keep in mind that it is very expensive and can exceed $10,000 in some cases for a complete treatment.
In addition to these costs, the following costs may also be added:
- Veterinary visits
- Sedation or anesthesia
- Laboratory tests
- Imaging tests
If you cannot afford these expenses, you have other options such as:
- Payment plans offered by veterinary clinics
- Pet insurance (it has to be purchased before the diagnosis)
- Research centers or universities may offer treatment at a reduced cost as part of clinical trials.
- Non-profit organizations
Discuss any aspect, including financial, with your veterinarian and explore all options before starting treatment to ensure that your pet will receive the care they need.
Frequently Asked Questions (FAQs)
How long will a dog with cancer live?
The life expectancy of a dog diagnosed with cancer depends on several factors, including the type and stage of the cancer and your dog's overall health. In general, a dog diagnosed with cancer has an average life expectancy of only a few months (with or without treatment in some cases). Conventional treatments can extend a dog's life expectancy by a few months to years, depending on the type and stage of the cancer. Additionally, natural approaches, such as supporting the immune system and promoting overall wellness with complementary therapies, may help improve your dog’s quality of life and support their body during treatment.
Is it worth treating a dog with cancer?
Deciding whether to treat a dog with cancer is a personal and often difficult decision. This decision often depends on the type and stage of the cancer, as well as the prognosis and overall health of your dog. Treatment can prolong and improve life, but it can be expensive and emotionally distressing. If you are unsure about what to do, consider the pros and cons, the costs, and the quality of life for your dog. Also, talk to your veterinarian, who can help you make the best choice.
How do dogs act when they have cancer?
When a dog has cancer, they may show certain behavioral changes such as losing their appetite, being low in energy, lethargic, tired, having difficulty breathing, or becoming aggressive. In any case, when you see the slightest change in behavior in your dog, notify your veterinarian.
What do vets do when a dog has cancer?
When a dog is diagnosed with cancer, your veterinarian will discuss the next steps, including treatment options, quality of life assessment, regular check-ups, and costs. In many cases, your current veterinarian will refer you to a specialist (oncologist) for the best course of action. If your dog’s condition worsens, your veterinarian may recommend palliative care or humane euthanasia. The goal is always to ensure your dog’s comfort and well-being.
What does cancer on a dog's skin look like?
Skin cancer can present itself in many forms. It can appear as lumps, bumps, skin tags, wounds that don't seem to heal, dark or red spots, etc. It is important that when you notice anything suspicious on your dog's skin, you take them to the vet for evaluation and proper diagnosis.
How long can a dog live with skin cancer?
The average survival time for a dog with skin cancer depends on various factors such as the type of cancer, the dog’s response to treatment, and their overall health. In the case of melanoma, dogs can live up to 36 months after the surgical removal of the tumor (and if there are no metastases). A dog with squamous cell carcinoma can have a life expectancy of 1 to 3 years after surgery.
How long can a dog live with Stage 4 cancer?
The survival time for dogs with stage 4 cancer depends on the type of cancer, its location, the dog’s response to treatment, and their overall health, However, in general, without treatment the survival time is a few weeks; dogs undergoing treatment have an average survival time of a few months to a year, in most cases.
Should I put my 12-year-old dog through chemo?
A dog's age should not influence a veterinarian's recommendations for a prognosis as long as the pet is systemically healthy. Therefore, age does not matter if the pet is treatable and if treatment will improve their quality of life.
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