Cancer and Tumors in Dogs

What tumours in dogs mean and what to look out for.

At a glance

What is it?: Uncontrolled cell growth; tumours can be benign or malignant.
Typical signs: Lumps that don’t go away, weight loss, lethargy, wounds that don’t heal.
Commonly affected: Mainly older dogs; some breeds have a higher risk.
Diagnosis: Palpation, blood tests, imaging, and a cell sample or biopsy.

Reading time 3 minutes Senior dogs

When should you see a vet?

Have any new lump looked at promptly. Go to the vet straight away if:

a lump grows quickly, changes or bleeds,
your dog is short of breath, suddenly collapses, has pale mucous membranes or a swollen belly,
they are lame for no apparent reason or lose a lot of weight.

What are cancer and tumors?

A tumor is a growth of tissue caused by uncontrolled cell growth. Benign tumors usually grow slowly, do not invade surrounding tissue and do not spread. Malignant tumors, that is cancer, can grow into surrounding tissue and form secondary tumors (metastases) in other organs. Many lumps in dogs are benign. But whether a lump is benign or malignant can only be determined at the vet.

What are the risk factors?

Age: The risk increases with age.
Breed: Some breeds are more prone to certain types of cancer.
Environment: For example, secondhand smoke or certain chemicals are discussed as risks.
Hormones: Some tumors, for example of the mammary glands, are linked to hormones.

Which signs should you watch for?

lumps or swellings that don’t go away or that grow
weight loss or loss of appetite
lethargy and less interest in exercise
problems breathing, swallowing, urinating or passing stool
wounds that don’t heal, or bleeding
lameness or pain without an obvious reason

How does the vet make the diagnosis?

Palpation and examination
Cell sample: Cells are collected with a fine needle and examined.
Biopsy: A tissue sample confirms the diagnosis.
Blood values and imaging: X-rays, ultrasound, CT or MRI show whether and where tumors have spread.

Which breeds are particularly affected?

Some breeds have a higher risk of certain types of cancer, for example:

Golden Retriever: lymphomas and hemangiosarcomas
Bernese Mountain Dog: histiocytic tumors
Boxer: mast cell tumors
Rottweiler: bone cancer (osteosarcoma)

Ask your vet what you should pay particular attention to with your dog.

What you can do in everyday life

Feel your dog over regularly, for example while brushing.
Note the size and location of lumps, so you can spot changes more easily.
Have every new lump looked at promptly instead of waiting.
If your dog is ill, fixed routines, rest and lots of attention provide security. You decide on treatment and feeding together with your vet.

Frequently asked questions about Tumours

Is every lump cancer?

No, many lumps are benign. Whether a lump is benign or malignant can only be said for certain with a cell sample or biopsy.

Should I wait and see with a new lump?

Better not; have it looked at promptly. Note its size and location so that changes are easier to spot.

Which dogs are particularly at risk?

The risk increases with age, and some breeds are more prone to certain types of cancer. Ask your vet what to look out for in your dog.

What can I do day to day?

Feel your dog over regularly and watch for changes in behaviour. Fixed routines, calm and lots of attention are good for them.

Veterinary expertise at the heart of our team

Dr. med. vet. Sibylle Ott has been part of our team at DOG FIT by PreThis^® from the very beginning. As an experienced vet, she supports our work professionally and contributes her knowledge of dog health. Her experience and her deep understanding of dogs’ needs are an important guide for us. She is a valuable treasure for our team and for the well-being of many dogs.

This content is for information only and does not replace advice from a vet. Our products are complementary feed for dogs. They do not replace a veterinary examination or treatment. If your dog has any health problems, please contact your vet.