Rising Dog Cancer: One in Four Pets Now Faces a Lifetime Diagnosis and Breeds at Risk for Cancer (What to Watch For)
Mast Cell Tumors (MCTs)
Mast cell tumors are one of the most common skin cancers in dogs. They usually show up as raised, red lumps on the skin, but they can also develop inside the body (like in the liver or spleen). Some can look just like harmless fatty lumps, so it’s always worth getting any new bump checked.
Vets often use a simple test called a fine needle aspirate (basically taking a few cells from the lump) to figure out what it is.
Breeds to watch more closely:
Boxers (common, usually less aggressive)
Pugs (common, often less aggressive)
Shar-Peis (common and more aggressive)
What you can do:
Regularly check your dog for new lumps or changes
Have your vet examine any new bump
Schedule at least yearly vet visits
Melanoma
Melanoma is a cancer that starts in pigment-producing cells. In dogs, it most often shows up in the mouth, but it can also affect toes (digits).
Signs to watch for:
Bleeding in the mouth
Trouble chewing
Pawing at the mouth
Bad breath
Limping or swelling in a toe
Breeds at higher risk:
Miniature Schnauzers
Scottish Terriers
What you can do:
Make sure your vet checks your dog’s mouth and toes, especially as they age
Get any suspicious mass biopsied quickly
Early detection really matters here.
Osteosarcoma (Bone Cancer)
This is an aggressive bone cancer that tends to affect large dogs. It often shows up as sudden limping, pain, or swelling—usually in the legs.
Breeds at higher risk:
Rottweilers
Irish Wolfhounds
Greyhounds (may also be more prone to fractures)
Diagnosis usually involves X-rays of the limb and chest.
What you can do:
There’s no proven way to prevent it yet
Take any sudden lameness seriously and get it checked right away
Transitional Cell Carcinoma (TCC)
TCC is a cancer of the bladder and urinary tract. It’s the most common urinary cancer in dogs.
Warning signs:
Blood in the urine
Frequent or strained urination
Accidents in the house
Pain when urinating
Breeds at higher risk:
Scottish Terriers (very high risk)
Beagles
West Highland Terriers
Shetland Sheepdogs
What you can do:
Don’t ignore urinary symptoms—even if they seem like a simple infection
Avoid lawn chemicals, especially for high-risk breeds
For Scottish Terriers, diets including vegetables several times a week may reduce risk
Brain Tumors
Brain tumors are more common in dogs over age 5. The most frequent types are meningiomas (often benign) and gliomas (more aggressive).
Common signs:
Seizures (especially in dogs with no history of seizures)
Behavior changes
Vision problems
Balance issues or unsteadiness
Head tilt or neck pain
Nausea or vomiting
Breeds at higher risk:
Boxers
Collies
Pugs and other short-nosed breeds
Possibly Golden Retrievers, Dobermans, Scottish Terriers, and Old English Sheepdogs
What you can do:
Treat neurological symptoms as urgent
Diagnosis typically requires advanced imaging (CT or MRI)
Gastric Carcinoma (Stomach Cancer)
This is a rare but serious cancer in dogs, often diagnosed late.
Signs to watch for:
Vomiting
Diarrhea
Bloating
Weight loss
Loss of appetite
Low energy
Breeds at higher risk:
Chow Chows
Belgian Shepherds
What you can do:
Don’t ignore ongoing digestive issues
Get symptoms evaluated early, since this cancer is often found after it has spread
A Quick Note on People and Pets
Many of these cancers also occur in humans, and research in dogs is helping scientists better understand and treat cancer in both species. This field is called comparative oncology—and it’s an important area of ongoing research.