Be sure to keep an eye on your dog’s mouth and feet to make sure you don’t see any unfamiliar masses.

When it comes to melanoma in dogs, the best thing you can do is keep a close eye out for masses in your dog's mouth, around her paws, and on her skin. If you see anything, contact your vet immediately.

"I think just really just keeping an eye out," says oncologist Angela Taylor, DVM, DAC. "There's really no way to prevent a lot of cancers."  

Here's what else you need to know about this dangerous and sometimes fatal cancer in dogs:

What Is Canine Melanoma?

Melanoma is cancer of the melanocytes, which are the cells that make melanin, the pigment that gives your dog's skin and hair their colors. The cancer appears as a tumor, most commonly in your dog's mouth but sometimes in her paw pads or near her toe nails, Taylor says. Occasionally, dogs will sprout the tumors on the skin under their hair, but those tumors are usually benign, she adds. Another rarer melanoma location: inside the eyes or eyelids. 

According to Patty Khuly, DVM, older dogs are most prone to melanoma, especially the oral version, which is aggressive. Oral melanoma makes up 40 percent of tumors found in dogs' mouths. It's generally considered a fatal illness.

As with most cancers, it's hard to know what causes melanoma in dogs, Taylor says, though researchers don't think it has anything to do with sun exposure (unlike human melanoma). It might just be bad luck or genetics depending on the kind of dog you have (more on that later). 

The first sign your dog has canine melanoma might be a mass in her mouth or on her foot, but there are plenty of other things you should look out for, too.

bulldog on sunny dock
Credit: Lunja / Getty

Signs of a Melanoma in Dogs

Generally, you'll want to keep an eye out for both a mass and whether your dog is experiencing pain in her mouth or feet. It's most likely that your dog will suffer from some form of oral melanoma, so here's what Taylor says you should look out for: 

  • Bleeding from the mouth
  • Bloody saliva
  • Trouble chewing food or preferring one side of the mouth to chew over the other
  • Locating a mass

To make sure your dog does indeed have melanoma, contact your veterinarian. 

Melanoma is probably one of the worst things your dog can go through. First, your poor pup will experience pain in the mouth from the mass, Taylor says. But then the tumor will spread to the lymph nodes and eventually the lungs, making it hard for your dog to breed and causing exercise intolerance and coughing.

There are stages of oral dog melanoma, based on the size of the tumor. According to BluePearl Pet Hospital, dogs with stage I melanoma will usually live on for months, maybe even over a year, while stage IV patients may only have weeks. 

However, some dogs do get rare, low-grade oral melanoma, which they can live with, Taylor says.

Dog Breeds Most Susceptible to Melanoma

Dogs with darker skin, including dogs with dark skin around their mouths, are usually "overrepresented" in the data of dogs who suffer from melanoma, Taylor says. It's perhaps because they have more melanin-producing cells, she adds.

Although there's not a definitive link to melanoma, breeds like golden retrievers, black Labrador retrievers, chow chows, and Bernese mountain dogs can also be susceptible. If you have one of these breeds—or even if you don't—it might be a good idea to give your dog routine once-overs.

How to Treat Melanoma in Dogs

Sadly, there aren't many options here and treatment is more centered around pain management. Surgery to remove the tumor is often the best choice if a surgeon is able to do it, Taylor says. It can limit pain and help your dog live longer. Some tumors will be in inaccessible places, however, like in the back of a dog's mouth. Otherwise, radiation treatments can help limit the pain locally.

Then there's the canine melanoma vaccine, which can be given to dogs with stage II or III oral melanoma. It's designed to help prolong life and limit pain along with surgery or radiation therapy. However, Taylor says questions have arisen recently about how effective it really is.

On the flip side of that, aside from monetary cost, the vaccine won't hurt your dog, so it might be worth a try.

"There's no harm in getting it, it's just whether or not it benefits the pet," she says.    

Not Much You Can Do to Prevent Melanoma in Dogs

That's maybe the crappiest part of all this: We're not sure what causes canine melanoma and there's not really a way to prevent it. 

The best thing you can do is catch it early. That means going into the vet's office for regular checkups and examining your dog at home yourself, Taylor says. Heck, this is another reason to brush your dog's teeth—to get in there and make sure you can't find anything that looks out of the ordinary.

If you find it early, you and your vet can get to work on making sure your dog lives the rest of her life in as much comfort as possible.