5 Most Common Cancers That Canines Suffer From

Understanding the most common cancers that affect dogs can help owners recognise potential warning signs earlier and seek timely veterinary evaluation.

1. Canine Lymphoma

Canine lymphoma is one of the most frequently diagnosed cancers in dogs, making up 24% of canine cancer cases. It affects the lymphatic system, which plays a key role in the body’s immune function. As lymphatic tissue is found throughout the body, lymphoma can develop in many different areas, including the lymph nodes, liver, spleen and bone marrow.

Dogs with lymphoma often develop enlarged lymph nodes, which may first appear as painless swellings under the jaw, in front of the shoulders or behind the knees. The liver, spleen and bone marrow can all be affected by lymphoma. Other symptoms may include lethargy, loss of appetite and weight loss.

Treatment typically involves chemotherapy sessions that aim to control the disease and maintain quality of life. Early-stage lymphoma has a relatively high survival rate when treated with chemotherapy.

2. Osteosarcoma

Osteosarcoma is the most common type of skeletal cancer that dogs can develop. This condition mainly affects large dog breeds, first appearing as highly aggressive tumours in longer bones of the limb. This cancer often begins as a rapidly growing tumour within the bone, which can weaken the bone structure and lead to bone destruction. Osteosarcoma has a high tendency to spread to other parts of the body, most commonly the lungs, through a process known as metastasis.

Dogs with osteosarcoma may show signs such as persistent lameness, swelling around the affected limb or reluctance to bear weight. The condition can progress quickly and may spread to other parts of the body. Treatment options often include surgery, chemotherapy or a combination of both.

3. Melanomas

Melanomas are cancers that develop from melanocytes, the cells responsible for producing pigment in the body. In dogs, these tumours most often occur in the mouth, lips, nail beds and skin. While some melanomas grow slowly and remain localised, others can be aggressive and spread to surrounding tissues or distant organs.

Cutaneous or skin melanomas are generally less likely to be malignant compared to those that develop in the mouth or toes. They often appear as dark brown or black raised masses on the skin, although some may be pink or hairless. These growths may gradually increase in size and can occasionally ulcerate or bleed if irritated.

Oral melanomas are among the most aggressive types of canine cancer. They typically develop along the gums, lips, tongue or roof of the mouth and can invade nearby bone or soft tissues. Dogs with oral melanoma may develop persistent bad breath, excessive drooling, bleeding from the mouth or difficulty chewing and swallowing.

Diagnosis usually involves a physical examination followed by tests such as a biopsy or imaging to determine whether the tumour has spread. Treatment options depend on the tumour location and stage, and may include surgical removal, radiation therapy or immunotherapy.

4. Mast Cell Tumours

Mast cell tumours are among the most common skin cancers in dogs. They develop from mast cells, which are part of the immune system and normally help the body respond to inflammation and allergic reactions. When these cells grow uncontrollably, they can form tumours on or under the skin.

These tumours can vary greatly in appearance. They may look like small bumps, raised lumps or larger masses on the skin, and can sometimes resemble harmless growths such as warts or fatty tumours. Mast cell tumours may also change in size, becoming swollen or red due to the release of histamine and other chemicals from the cancerous cells.

Dogs with mast cell tumours may experience symptoms such as itching, redness, ulceration or bleeding around the affected area. In some cases, the chemicals released by the tumour can cause additional signs such as vomiting, diarrhoea or stomach ulcers.

Treatment often involves surgical removal of the tumour along with surrounding tissue. Depending on the tumour grade and whether it has spread, additional treatments such as radiation therapy or chemotherapy may also be recommended.

5. Hemangiosarcoma

Hemangiosarcoma is an aggressive cancer that develops from the cells lining blood vessels. It most commonly affects organs such as the spleen, liver or heart, although it can also appear on the skin. Because it grows within blood vessels, the tumour is fragile and prone to rupture, which can lead to sudden internal bleeding.

This cancer is typically not noticeable in the early stages. In many cases, it is only detected once internal bleeding begins. Dogs may suddenly show signs such as weakness, pale gums, collapse, rapid breathing or abdominal swelling.

Treatment often includes surgery to remove the affected organ, such as the spleen, followed by chemotherapy to slow the spread of cancer. While hemangiosarcoma is considered a serious and aggressive disease, early detection and treatment may help extend survival time and improve the dog’s quality of life.

What Do I Do If I Suspect My Dog Has Cancer?

If you notice unusual changes in your dog’s health or behaviour, it is important to monitor the symptoms closely and seek veterinary advice as soon as possible. Early detection can help improve treatment options and may lead to better outcomes for your pet.

Some warning signs of cancer in dogs can be subtle at first. Keep an eye out for the following symptoms:

• Unusual lumps or bumps that continue to grow or change in size
• Swelling or tenderness that does not subside over time
• Unexplained weight loss and loss of appetite
• Bleeding or discharge from the mouth, nose or other body openings

If you notice any of these symptoms, it is advisable to arrange a veterinary consultation promptly.

We offer a wide range of services, from emergency and critical care to advanced diagnostics and preventive care. Advanced Vetcare operates 24/7, and we maintain a dedicated pet ICU that provides the highest standard of care day and night.

Contact us today to find out more or schedule a routine check-up for your pet.

Frequently Asked Questions (FAQs) About Canine Cancer

Are certain dog breeds more prone to cancer?

Yes, some breeds have a higher risk of developing certain types of cancer. Larger breeds such as Golden Retrievers, Boxers, Rottweilers and Great Danes are often more susceptible to cancers like lymphoma or osteosarcoma. However, cancer can occur in dogs of any breed.

At what age do dogs usually develop cancer?

Cancer is more commonly diagnosed in middle-aged to older dogs, typically from around 7 years of age onwards.

What treatment options are available for canine cancer?

Treatment options vary depending on the cancer type and stage. Common treatments include surgery to remove tumours, chemotherapy, radiation therapy and supportive care to manage symptoms. Your veterinarian will recommend a treatment plan tailored to your dog’s condition.

Can cancer in dogs be cured?

The possibility of curing canine cancer depends on the variety of disease, how early it is detected and whether it has spread to other parts of the body. Certain types of cancer can be excised with surgery, while others may be managed to slow progression and maintain quality of life.

Meet Our Veterinary Specialist in Singapore

Dr Nicholas WooConsultant Vet and SurgeonBVSc (Hons) MANZCVS (Small Animal Surgery)

Dr Nicholas Woo is a consultant vet and surgeon with a strong passion for animal care. Dr Woo has undergone specialised training in small animal surgery and oncology under renowned veterinary specialists, equipping him with experience in managing complex surgical and medical cases. His clinical interests include advanced soft tissue surgery, animal orthopaedics, oncological care, hip replacement, spinal surgery and critical care management.

In 2017, Dr Woo founded Advanced Vetcare with the aim of providing accessible, high-level veterinary care supported by modern medical facilities and round-the-clock emergency services.

Dr Woo has also presented at numerous veterinary meetings, where he shares his knowledge and experience with fellow professionals while contributing to ongoing developments in veterinary medicine.