Tumors in dogs are among the most common causes of death, especially in older animals. Statistics show that nearly half of dogs over ten years old will face some form of cancer during their lifetime. This is why it is crucial for owners to be aware of the symptoms of dog tumors, the most common tumor types, and the possibilities of early detection. The sooner a veterinary examination is carried out, the greater the chances of improving the dog’s quality of life and survival.
Poor nutrition, improper living conditions, genetic factors, environmental pollution, and stress can all contribute to the development of tumors. In this article, we have collected all the essential information about dog tumor types, their symptoms, and possible treatment methods.
Basics of dog tumors
Tumors are groups of cells that multiply uncontrollably when the balance between cell formation and cell death is disrupted. Tumors are classified into two main categories: benign and malignant.
It is important to understand that “tumor” and “cancer” do not mean exactly the same. Every cancer is a tumor, but not every tumor is cancerous. Benign tumors, for example, do not spread to other parts of the body, while malignant tumors can infiltrate surrounding tissues and form metastases. This difference determines both the treatment options and the outcome of the disease.
Benign dog tumor types
These tumors do not spread to other tissues or organs. While they may require medical intervention, they are not cancerous and usually do not endanger the animal’s life.
Malignant dog tumor types
These tumors are cancerous and capable of spreading to other organs, forming metastases. Depending on their type and aggressiveness, they can pose serious health risks to dogs. Treatment for malignant tumors often requires surgery, radiation therapy, chemotherapy, and other medical approaches.
Causes and risk factors of dog tumor types
The exact cause of dog tumors is not always known. Some types are more common in certain breeds, which suggests a genetic predisposition. Older animals are also more prone to tumors, since cellular damage accumulates over the years, increasing the likelihood of cancer. It is important to understand that these factors alone do not always cause tumors, but over time they can significantly raise the risk. This is why prevention and conscious environmental management are crucial.
- Environmental pollutants: exhaust fumes, cigarette smoke, industrial chemicals
- Chemicals: pesticides, herbicides, and household cleaning agents
- Stress: prolonged tension that weakens the immune system
- Low-quality food: high in carbohydrates and additives
- UV radiation: increases the risk of skin tumors
The development of tumors is influenced by several factors combined. While genetic predisposition cannot be completely eliminated, much can be done to maintain your dog’s health and prevent cancer by reducing environmental risks, providing nutritious food, and minimizing stress.
Dog tumor types and prevention tips for owners
Although the occurrence of dog tumors cannot always be completely prevented, much can be done to reduce the risks. Quality nutrition, avoiding harmful environmental factors, and regular veterinary check-ups all contribute to helping our pets live healthier and longer lives.
- Healthy diet: Your dog’s food should be free of artificial additives. Avoid gluten-containing foods, as they may cause inflammation that promotes tumor development. Choose treats with low carbohydrate content and natural ingredients.
- Clean environment: Chemicals, exhaust fumes, and tobacco smoke can all increase the risk of tumors. Keep your dog in a smoke- and chemical-free environment and use natural cleaning products whenever possible.
- Regular exercise: Physical activity strengthens the immune system, helps maintain healthy body weight, and lowers the risk of cancer. Daily walks, play, and free movement are essential for your dog’s well-being.
- Stress reduction: Prolonged stress weakens the immune system, raising the risk of dog tumors. Provide a calm environment, sufficient sleep, and plenty of positive interaction for your dog.
- Veterinary screenings: Annual check-ups and timely diagnostic tests (such as blood tests, ultrasound, x-rays) help detect tumors early. The sooner the diagnosis is made, the better the chances of successful treatment.
Early symptoms of tumors in dogs
Cancer in dogs often develops stealthily, with mild symptoms at first. Owners must recognize the early warning signs, since early diagnosis greatly improves treatment success and the dog’s survival chances. While symptoms vary depending on breed and tumor type, there are general signs that should always raise concern. For a more detailed overview, read our article on the symptoms of dog tumors.
If any of these symptoms persist or worsen, an immediate veterinary examination is required. Many owners tend to delay, but every lost week decreases the chances of successful treatment. Early detection of tumors often makes the difference between complete recovery and an advanced, hard-to-treat condition.
Dog tumor types and their symptoms
There are many dog tumor types, and the symptoms vary depending on whether the tumor is benign or malignant, and which organ or tissue is affected. Tumors in dogs often develop slowly, so owners may only notice the signs later. This is why it is crucial to be familiar with the symptoms of the most common cancers, as early detection can save lives.
Malignant dog tumor types
Malignant tumors are groups of cells that grow uncontrollably, infiltrate surrounding tissues, and often form metastases. These cancerous tumors pose serious health risks, can spread quickly, and may be life-threatening. Their treatment is complex, often requiring surgery, chemotherapy, radiation therapy, or immunotherapy. Early detection is key to improving survival chances. Malignant tumors can affect any organ, including the central nervous system. Brain tumors form a separate category, which we discuss in detail in another article.
Mast cell tumor (mastocytoma)
This malignant tumor develops from the mast cells in a dog’s skin. These cells are normally part of the immune system, but in cancerous conditions they multiply abnormally. Mast cell tumors can appear in many forms: as small lumps, pimple-like lesions, or even resembling benign lipomas. They most commonly occur in beagles, boxers, bulldogs, bullmastiffs, golden retrievers, labradors, and pugs.
Typical symptom: various skin changes, lumps under the skin of different size and shape.
Mammary tumor
Mammary carcinoma is among the most common tumors in female dogs. Those at greatest risk are unspayed females, or those spayed only after their second heat. Half of mammary tumors are benign, but only a histopathological examination can confirm this. Breeds at higher risk include poodles, English spaniels, English setters, and terriers.
Typical symptom: lumps in the mammary glands, swelling in the area, usually in unspayed females.
Lymphoma
Lymphoma is a malignant tumor of the lymphatic system, originating from lymphocytes (white blood cells). Common breeds include golden retrievers, boxers, bullmastiffs, basset hounds, Saint Bernards, and Scottish terriers.
Typical symptom: large, firm lymph nodes (around the jaw, in front of the shoulders, behind the knees), along with lethargy and loss of appetite.
Thyroid cancer
This malignant tumor of the thyroid gland arises from the gland’s cells. A neck swelling is often only noticed late, sometimes after the cancer has already spread to other organs. It is more common in golden retrievers, beagles, and boxers.
Typical symptom: swelling on the neck, often detected only at an advanced stage.
Osteosarcoma (bone sarcoma)
Osteosarcoma is a malignant bone tumor that is extremely painful and often leads to bone fractures, limb swelling, and lameness. It occurs most frequently in large breeds such as boxers, golden retrievers, German shepherds, Great Danes, Pyrenean mountain dogs, greyhounds, labradors, and rottweilers.
Typical symptom: lameness, limb swelling, severe pain, spontaneous bone fractures.
Melanoma
Melanoma is a malignant tumor that develops from pigment-producing cells (melanocytes). It often appears in the oral cavity but may also occur in the eye, nail bed, or skin. It is more common in schnauzers and Scottish terriers.
Typical symptom: pigmented or pink lesions in the mouth, eye, nail bed, or on the skin.
Benign dog tumor types
Benign tumors are groups of cells that grow slowly and do not form metastases. These non-cancerous tumors generally do not pose a serious risk to the dog’s life, but sometimes require surgical removal. While they do not spread to other parts of the body, they may cause discomfort, pain, or mobility issues. Benign tumors in dogs are often removed for cosmetic or comfort reasons.
Histiocytoma
A histiocytoma is a benign tumor that originates from histiocytes (immune cells) in the skin. It often regresses spontaneously within a few weeks. It is most common in dogs under 2 years of age, particularly in labradors, boxers, shar peis, bulldogs, pitbull terriers, staffordshire terriers, and Scottish terriers.
Typical symptom: small, round lumps on the skin surface, which appear in young dogs and often disappear spontaneously.
Lipoma
A lipoma is a benign tumor that develops from fat cells in the fat layer under the skin. Although it can grow large, it does not pose a serious health risk. Lipomas are typically soft, movable lumps that usually cause no pain. Breeds at higher risk include the Weimaraner, Doberman, German shorthaired pointer, English springer spaniel, and labrador.
Typical symptom: soft, movable lumps under the skin, mostly harmless.
Papilloma
A papilloma is a benign skin tumor caused by the papillomavirus. It most often appears as wart-like growths, which usually regress on their own. Since it spreads through contact, it is more common in community settings such as dog parks or daycares.
Typical symptom: warty growths on the lips, tongue, throat, or gums, which usually disappear spontaneously.
When should you see a veterinarian?
Many owners tend to wait when noticing small changes in their pet, but with cancer, time is the most important factor. The earlier the veterinary examination, the greater the chance of successful treatment. Therefore, any suspicious sign should be addressed by a veterinarian without delay.
If you notice any of these symptoms, do not wait – make a veterinary appointment immediately.
Diagnosing dog tumor types
Early diagnosis plays a key role in treating cancer in dogs. Identifying the exact type of tumor is essential for the veterinarian to select the most effective therapy. The diagnostic process involves several steps to determine the location, size, type, and possible metastases of the tumor.
The veterinarian uses the results to create a treatment plan. Diagnosis not only identifies the disease but also reveals the tumor’s extent and stage. This determines whether complete recovery is possible or whether the focus shifts to improving quality of life.
Treatment options for dog tumor types
Treating cancer in dogs is always personalized, as the therapy depends on the tumor’s type, location, size, and the dog’s overall health. The veterinary oncologist selects the best method, often combining different therapies. The goal may be full recovery, but in advanced cases, pain relief and quality of life become the priority.
Every dog is unique. Combining therapies often increases success compared to a single method. Ongoing consultation with the veterinarian and regular monitoring are essential for long-term success.
The role of medicinal mushrooms in treating dog tumors
Medicinal mushrooms are increasingly recognized in veterinary oncology as complementary therapies. They do not replace surgery, chemotherapy, or radiation, but research shows they support the immune system, improve overall condition, and reduce side effects of conventional therapies. The most commonly used are reishi, turkey tail, maitake, shiitake, and cordyceps.
Reishi (Ganoderma lucidum)
A powerful antioxidant and immunomodulator. Research suggests it slows tumor growth and eases chemotherapy side effects.
Turkey tail (Trametes versicolor)
One of the most studied mushrooms. Its beta-glucans strongly activate immune cells, aiding cancer defense. It is useful as adjunct therapy during treatment and supports recovery.
Maitake (Grifola frondosa)
Its beta-glucans stimulate immune cells and may help in cancer defense, as well as in complementary therapy.
Shiitake (Lentinula edodes)
Contains lentinan, an immunomodulating polysaccharide. It enhances immune response and contributes to fighting tumors.
Cordyceps (Cordyceps sinensis)
Improves cellular energy and oxygen use, strengthens resistance, and may inhibit cancer cell growth.
Always consult a veterinarian before using mushrooms. Proper dosage and therapeutic combinations are key for safe and effective support.
Can dog tumors be cured?
The curability of dog tumors depends on type, stage, and timing of diagnosis. Some localized tumors can be completely removed surgically, offering good chances of full recovery. In other cases—especially metastatic cancers—treatment focuses on quality of life and pain relief rather than cure.
Owners must understand that early detection is critical. The sooner a vet is consulted, the greater the chance the tumor is operable and treatable. In advanced cases, veterinary oncologists aim to prolong life, ensure comfort and pain-free living, and slow disease progression.
The role of the veterinary oncologist
When a dog is diagnosed with cancer, one of the most important steps is consulting a specialist veterinary oncologist. They assess the tumor’s type and stage and create a personalized treatment plan. The oncologist’s role includes not only presenting treatment options but also supporting owners in decisions and ensuring long-term quality of life.
The oncologist explains all possible treatments, including surgery, radiation therapy, chemotherapy, immunotherapy, and complementary natural therapies such as mushrooms. Treatment goals depend on the dog’s condition: sometimes full recovery is possible, but often the focus is on extending life and ensuring pain-free days.
While dog cancers are a serious challenge, early detection and involving a specialist oncologist greatly improve outcomes. Alongside conventional therapies, natural supplements such as reishi, maitake, shiitake, cordyceps, and turkey tail can support immunity and fight cancer cells. Consulting an oncologist is not just about treatment planning, but also about reassurance, clarifying options, and ensuring the best possible quality of life during illness.
Summary of dog tumor types
Dog cancers are a major challenge for both pets and owners. Early detection and proper treatment are crucial for recovery. Alongside conventional treatments, medicinal mushrooms can support the immune system and help fight cancer cells. Regardless of tumor type, alternative options are generally similar. Veterinary oncologists and detailed diagnostics help build the best plan so that dogs can achieve the best possible quality of life.
Frequently asked questions about dog tumors
❓ What are the most common early symptoms of dog tumors?
Early signs include palpable lumps, swelling, loss of appetite, weight loss, lethargy, persistent coughing or breathing difficulties. Digestive issues, unusual discharges, or lameness may also indicate a problem. If these symptoms occur, it is important to consult a veterinarian immediately.
❓ Can dog tumors be cured?
Some tumors can be completely removed surgically if detected early, allowing the dog to fully recover. In more advanced cases, treatment often focuses on prolonging survival and improving quality of life. The exact prognosis always depends on the type and extent of the tumor.
❓ Which dog breeds are more prone to tumors?
Some breeds are more prone to certain tumor types. For example, boxers, golden retrievers, and labradors are more likely to develop lymphoma and mast cell tumors. Large breeds such as German shepherds or rottweilers are more likely to suffer from bone tumors. However, any breed or mixed-breed dog can be affected.
❓ When should I see a veterinarian about a suspicious lump?
Every newly detected or growing lump should be examined by a veterinarian, especially if it is hard, grows quickly, or if changes in the dog’s behavior are noticed. Delaying reduces the chances of successful treatment, so it is always best to consult a professional promptly.
Learn more about dog tumors
- Osteosarcoma in dogs
- Hemangiosarcoma in dogs
- Lymphoma in dogs
- Dog mammary tumor
- Mast cell tumor in dogs
- Brain tumors in dogs
Important: This article is for informational purposes only and does not replace veterinary examination or treatment. For an accurate diagnosis and appropriate therapy, always seek your veterinarian’s advice.
References
- Arendt, M. L., et al. (2025). Genetics of canine cancer: a guide for the veterinary oncologist. Veterinary Oncology.
- Komazawa, S., et al. (2016). Canine tumor development and crude incidence. PMC.
- Paździor-Czapula, K., Rotkiewicz, T., Otrocka-Domagała, I., Gesek, M., & Śmiech, A. (2015). Morphology and immunophenotype of canine cutaneous histiocytic tumours with particular emphasis on diagnostic application. Veterinary Research Communications, 39(1), 7-17.
- Srisawat, W., Pringproa, K., Prachasilchai, W., Thongtharb, A., & Sthitmatee, N. (2024). Epidemiology and classification for canine and feline mammary gland tumors: a histopathological survey of 437 mammary gland tumor biopsies performed in a secondary care hospital in Chiang Mai, Thailand from 2012 to 2019. PeerJ, e17077.
- Tarone, L., et al. (2019). Naturally occurring cancers in pet dogs as pre-clinical models. PMC.
