Lymphoma in dogs

Lymphoma in dogs is a cancer of their body’s immune system. It’s one of the most common types of cancer, affecting up to 1 in 1000 dogs. Lymphoma in dogs is rarely curable. Treatment aims to control the cancer and to improve the symptoms. Lymphoma can develop in any dog, but it’s most likely in middle-aged to older dogs and certain breeds.

Lymphoma in dogs happens when lymphocytes start to multiply out of control. Lymphocytes are a type of white blood cell and are part of the body’s immune defences. There are different types of lymphoma in dogs, which affect different parts of the body. Symptoms will depend on the location and spread of the cancer. Life expectancy with treatment is on average 6-12 months. Life expectancy depends on the type of lymphoma, stage and response to treatment. Outlook for remission is best when the lymphoma is identified and treated promptly. Call a vet as soon as possible if you notice a new lump or swelling on your dog.

Overview

What is lymphoma in dogs?

Lymphoma in dogs is a cancer of white blood cells. These cells usually protect the body from infections. Lymphoma in dogs accounts for 15-20% of cancers diagnosed by vets each year.

Lymphoma is a cancer of white blood cells called lymphocytes.
Lymphocytes are made in the bone marrow. They help the body to fight infection and disease.
Lymphoma usually develops in lymphoid tissue, the body’s ‘battlegrounds’ against infection.
Common sites for lymphoma include peripheral lymph glands, liver, spleen, bone marrow.
There are different types of lymphoma in dogs, including multicentric, gastrointestinal, mediastinal (chest) and cutaneous (skin)
Lymphocytes travel throughout the body, so the cancer spreads easily to multiple organs or tissues
Lymphoma in dogs can rarely be cured. It will eventually result in death.
Life expectancy with treatment is 6-12 months but less without treatment or with poor response to treatment

Call a vet as soon as possible if you find a new lump on your dog.

Symptoms

Symptoms of lymphoma in dogs

Symptoms of lymphoma in dogs will depend on the type of lymphoma and organs or tissues involved.

Multicentric lymphoma is the most commonly recognised form of lymphoma.

80-85% of all lymphomas in dogs.
You may notice painless swelling of one or more of your dog’s peripheral lymph glands.
Peripheral lymph glands (lymph nodes) are paired glands located throughout the body.
5 of the pairs are just under the skin and easily felt if enlarged.
- Submandibular (beneath the angle of the jaw area;
- Prescapular (in front of the shoulder blade, near the chest);
- Axillary (armpit);
- Inguinal (inside the thigh, in the groin);
- Popliteal (behind the knees).

General symptoms

Weight loss
Dullness and depression
Loss of appetite
Vomiting and diarrhoea
Hair loss
Difficulty breathing with cancers in the chest
Swelling of the face and neck

High blood calcium level(hypercalcaemia) is a serious complication with some types of lymphoma.

Associated symptoms include:

Drinking more
Urinating (peeing) more
Irregular heartbeat resulting in weakness, loss of energy, and collapse.

Risk

Which dogs are most at risk of getting lymphoma

Whilst any dog can get lymphoma, there are recognised and suggested risk factors:

Belonging to certain breeds: Golden retriever, Bulldog, Poodle Boxer, Scottish Terrier, Basset Hound, Airedale Terrier, Chow Chow, Cocker Spaniel, German Shepherd, St. Bernard, Bulldog, Beagle, Rottweiler
Being middle-aged to older
Being exposed to environmental pollutants and toxins

Risks to people and other dogs

Lymphoma is a disease of individual dogs. It won’t spread between dogs or from dogs to people or other animals.
Dogs who share the same genetic and environmental factors will be equally at risk.
Chemotherapy drugs to treat lymphoma are hazardous to dogs and people they’re not prescribed for. Careful handling and strict hygiene are essential.

Diagnosis

How do vets diagnose lymphoma in dogs?

The first stage of diagnosis of lymphoma in dogs is usually the discovery of one or more enlarged lymph glands. Vets carry out further tests to confirm the diagnosis:

Fine needle aspirate: Collecting cells from the lump to examine under a microscope
Biopsy: Removing a larger piece of the lump or a whole lymph gland for more detailed assessment.

Once the diagnosis is confirmed, further tests check the spread and effects elsewhere in the body:

Chest x-rays and abdominal ultrasound
Blood tests

Your vet may advise referral to a cancer specialist, an oncologist, for further investigation and treatment.

Finding out more about the type of lymphoma, the stage (spread) and the best treatment options:

Advanced imaging: MRI, CT scan
Urinalysis
Bone marrow aspirates: collecting samples where lymphocytes are made
IHC (immunohistochemistry): This can help to identify the type of lymphoma.

Vet treatment

How can vets treat lymphoma in dogs

There’s no cure for lymphoma in dogs. The treatment goal is remission. This means reducing the symptoms and signs of the cancer. And above all, maintaining your dog’s quality of life.

The best treatment available for lymphoma is chemotherapy. Chemotherapy drugs kill cancer cells. There are multiple drugs and combinations of drugs used to treat lymphoma in dogs. 3 drugs are commonly used:

Cyclophosphamide
Vincristin (Oncosin)
Prednisolone

Each of these drugs acts against cancer cells in a different way. But they are even more effective when used in combination to tackle the cancer cells from multiple angles. This is called the COP protocol.

Chemotherapy begins with a higher induction dose to control and reverse symptoms.
Treatment gradually reduces to a maintenance level as tumours shrink and symptoms improve.
Chemotherapy pauses after 6-12 months. This will depend on the protocol your vet uses and your dog’s response to treatment.
Close monitoring and regular tests continue so we can identify any recurrence of the cancer as soon as possible.

Side effects are relatively mild on this protocol, but can include:

Vomiting and diarrhoea
Reduced appetite

A 4th drug, called Doxorubicin (Hydroxydaunorubicin) may be added to the COP protocol. This is the CHOP protocol. CHOP and other more complex individual protocols may achieve remission where simpler treatments fail. However, this comes at the cost of greater risk and severity of side effects.

Radiotherapy is occasionally used alongside chemotherapy for some types of lymphoma, especially in the skin.

Home treatment

How to care for a dog with lymphoma at home

There are no home remedies for lymphoma in dogs. During their illness and any treatment, the best we can do is to prioritise their quality of life.

Give all medicines exactly as prescribed by your vet
Handle chemotherapy drugs carefully and dispose of packaging or unused medicine as directed by your vet
Always wear gloves if cleaning up after a dog on chemotherapy
Let your dog rest in a warm, quiet and comfortable place
Feed a high-quality diet. This may be a special prescription diet, such as Hills Prescription Diet On-Care or a/d, where appetite is poor.
Go for short walks as long as your dog is able and still keen to have a sniff or explore outside
Keep a careful eye on their breathing rate and depth, urine and faeces (poo) production and weight changes.

Even with intensive treatment, life expectancy for dogs with lymphoma is unlikely to be more than a year. At some point, their health will deteriorate and their quality of life will worsen. When this happens, euthanasia is the kindest option. By this time you will have travelled a traumatic and heart-wrenching journey with your dog. Talk to your vet and those who share your dog’s care early on about how and when you will make this decision together. Monitoring quality of life regularly and objectively with the accompanying tool may help.

Prevention

Can lymphoma in dogs be prevented?

There is no way to prevent lymphoma in dogs. There’s rarely one absolute cause. Like any cancer, multiple things can contribute to risk. And early identification of cancer offers the best chance of achieving remission.