Don’t dismiss these symptoms.

Get your pet to the vet right away.

Early detection can improve your dogs chances of beating the disease and living a long, happy life.

Older dog lying on a couch, looking relaxed and content

We asked three vets what the earliest signs of cancer are in dogs.

This is, she says, typically the very clue that a dog has cancer.

The behavior change can be so slight that its only noticeable to someone in the family.

A human hand gently holds a dog's paw, conveying a bond between the person and the animal. The dog's paw is resting comfortably in the human's palm

Your dog, for example, might suddenly stop begging for a treat when you prepare your coffee.

They may also seem more lethargic than usual.

This can be mild or severe and may happen quickly or progress over days to weeks, Rebhun said.

A dog with a spotted black and white coat sits attentively on the back of a gray couch. A blanket is draped over the couch, and there is a wooden table in the background

These types of routine or behavioral changes could indicate your dog is in pain.

Most cancers cause systemic inflammation in the body and that inflammation can make your dog feel unwell.

Basically, it makes you feel blah, Bulman-Fleming said.

A dog eating from a metal bowl on a wooden floor in a cozy, modern living room

Rebhuns advice: Get any and all masses checked out.

Theyre suddenly super thirsty and peeing a lot

Some dogs with cancer incessantly lap up water.

Or, they may notice the dogs water bowl constantly needs to be filled up.

A dog with a white and brown face is peeking out from under a textured yellow blanket. The dog's expression appears calm yet slightly curious

Other types of cancers impact the kidneys, making your dog to pee more.

Cancer can also cause internal bleeding, and loss of blood can make your dog feel thirstier than usual.

These tumors can make it more difficult for dogs to get up and move around.

A curious brown dog with a black collar sits in a cozy room with a lamp, bed, and artwork in the background

In addition, many dog owners report that their dog suddenly becameuninterestedin their food.

According to Dervisis, those metabolic changes can also lower your dogs hunger levels.

Furthermore, tumors in their mouth, throat or stomach can make it painful or uncomfortable to eat.

This can lead to a noticeable decrease in how much food they consume, he said.