Three Common Signs of Oral Cancer

By: MJ Redman, DVM

TVMA Member
San Antonio, TX.

Published August 2017

The oral cavity is the fifth most common site for cancer in dogs and the third most common site for cats. Most oral tumors are treatable if detected early, and there are a variety of treatment options that can help most pets.

The term “cancer” is generally reserved for malignant tumors, which are those that can metastasize or spread to other parts of the body. Neoplasia is an abnormal growth of tissue, and if that tissue forms a mass, it is called a tumor. Doctors often use the term “epulis” to describe a mass on the gum tissue, giving off the perception that the growth is benign. However, an epulis is any abnormal growth on the gum tissue, but whether that growth is benign or malignant can only be determined by further testing.

Common Oral Tumors and Types of Cancer in Dogs and Cats

One of the most common growths in a dog’s mouth is a canine acanthomatous ameloblastoma, a slow-growing tumor. It can look innocent, but it is highly invasive. Surgical removal is curative but usually requires removing the tumor as well as a small margin of surrounding gum tissue, teeth and bone. It is best to remove these tumors when they are small.

The most common oral cancer in cats is squamous cell carcinoma, which also occurs in humans. This is a very aggressive cancer, but treatments such as surgery and pain medication help prolong the cat’s life. Some benign inflammatory conditions can resemble squamous cell carcinoma, making a biopsy vital for an accurate diagnosis. For most oral tumors in cats and dogs, we do not know the underlying cause or ways to prevent occurrence. Squamous cell carcinoma in cats is unique in that we know that exposure to cigarette smoke is a strong risk factor.

Clinical Signs of Oral Cancer

The three most common signs of a malignant oral tumor are:

  1. Swelling on the gums or jawbone: The swelling may look like normal gum tissue or be inflamed, bleeding or have a dark discoloration. The swelling can occur on the gums, tongue or roof of the mouth. Sometimes oral tumors are mistaken for a wound or an abscessed tooth because both can lead to swelling or bleeding. Some oral tumors cause teeth to loosen, a clinical sign that mimics periodontal disease. Others manifest themselves as an extraction site that will not heal.
  2. Foul-smelling breath: Bad breath is never normal for a dog or cat, but a tumor can smell like rotten meat because it contains dead tissue.
  3. Reluctance to eat: A dog or cat that used to eat dry food or crunchy treats may refuse to eat anything but soft food. They may take only small bites because it is painful to open their mouths.

Diagnostic Procedures and Treatment Options

If you notice any of these clinical signs in your pet, have your pet examined by a veterinarian immediately. The first step is to get a diagnosis. While some oral tumors have a distinctive appearance, most do not. A biopsy or complete removal of the mass (if it is small enough) is necessary to determine what kind of tumor is present. The biopsy involves removing a piece of tissue and sending it to a laboratory for analysis. Dental radiographs may be used to determine if the tumor involves the bone. Sometimes more than one biopsy is necessary to reach a diagnosis.

If a malignancy is present, metastasisthe development of secondary malignant growths at a distance from a primary site of cancer may be detected by taking X-rays of the chest or using a needle to collect cells from a lymph node. If pets exhibit signs of discomfort, they may require prescribed pain medication and/or antibiotics while waiting for results. Depending on the diagnosis, further surgery or tests like a CT scan are recommended. Complete removal of some oral tumors can result in a cure, so it is important not to delay the process of diagnosis and treatment.

MJ Redman, DVM, is a graduate of Washington State University who lives in San Antonio, Texas. Dr. Redman practices at MissionVet Specialty & Emergency and specializes in veterinary dentistry and oral surgery.

41 Responses

  1. Cordell says:

    My dog has really bad breath but doesn’t have any signs of a tumor what else can be causing his breath to be so bad

    • Siobhan Mulholland says:

      I would take your dog to the vets to be sure. Our Sheltie is really old we rescued her 3 years ago and has always had bad breath (also other symptoms) but she had an infection in her stomach and was given antibiotics which helped. Her breath smelt better and also her toilets as well as her vomiting stopped. She is old and has other things wrong with her now.
      But always best to have them checked by a vet, our vet knew with the smell of her breath what was wrong.

    • Holly soileau says:

      I just found out my dog of 13 years has a tumor under her tongue. Never noticed it but upon a dental cleaning it was found. Now it’s just time until we see the end I will treat her with meds but again I never seen this coming and she had horrible breath to plus her eating and drinking was off, food was only taken in small bites and even drinking was odd. Hope this helps you out

      • Holly says:

        It’s sounds identical to my ginger she is 14 .they found the tumor under tongue while getting a dental clean up because her breath was horrible. The tumor has interfered with drinking and eating she seems to be in pain. It’s hard to euthanize her when she still wants life it’s just life that hurts.we tried antibiotics and prednisone too it still grew now it’s worse.have to do what is right see her soon.

        • Chris Dizon says:

          Holly. My family is in a similar predicament with our 15 yo dog, Tally. I am interested to know what your family did for Ginger in the end.

      • Dave B says:

        Just found a mass under my 10yr old German Shepherd’s tongue,, was hoping for it to be a dental issue, maybe even a cracked tooth,, but both Vets at the animal Hospital feel that it is likely a cancerous tumor.. it came out of no-where unfortunately and has grown into an issue that affects his eating for sure.. Just nervous that,, if the mass affects the bone in his jaw too much more, then I will Have to put him down even though he’s full of life….

      • Thomas King says:

        So sorry you went that with your four legged child. My wife and I are currently in a similar situation. Just today we had the exact same diagnosis with our Maxwell, a 17 year old Blue Yorkie. I’m hoping you’ll receive this response as it’s about 3 years since your post and hoping you can maybe answer a few questions regarding his treatment and possible misdiagnosis. Wondering if it could be an infected abscess

    • Dana Landis says:

      Your dog may have a abscess, gum infection that can be caused by a build up of plaque and tartar on the teeth. Check your pets teeth especially the back ones. Your pets gums should be pink. If there is a build up on the teeth this will cause gum infection and very bad breath from the bacteria. If you do not get the teeth cleaned it can cause other health problems such as heart disease. Many times dental problems can cause watering eyes and other issues. Dental problems can also be very painful . I am not a vet but from my experience I would think your pet needs a dental and antibiotics. If there is not a issue dental issue it could be a digestive issue or some other condition.

    • Victoria says:

      Go to a very good vet and see if they can examine or test for cancer. My dog has always had bad breath since a puppy. Now at 13 he was diagnosed with oral cancer and I can’t help being haunted that the cancer was there all along and went undetected until the masses appeared in his mouth. The odor from his mouth now is unbearable and the vet is saying there is no Rx for the mouth odor and the tumors are inoperable. I pray for a miracle healing soon or his peaceful death soon.

    • Joseph says:

      Sometimes a tumor can’t be seen until the dog is put under and the dog’s entire mouth and throat is inspected. Tumors can and do hide under the tongue, and in other places that they can’t easily be seen. Therefore, it can go unnoticed.

  2. Holly says:

    It’s sounds identical to my ginger she is 14 .they found the tumor under tongue while getting a dental clean up because her breath was horrible. The tumor has interfered with drinking and eating she seems to be in pain. It’s hard to euthanize her when she still wants life it’s just life that hurts.we tried antibiotics and prednisone too it still grew now it’s worse.have to do what is right see her soon.

  3. Helen McKinney says:

    My wee dog had alot of teeth out at Xmas, ever since her tongue seems out of control I just assumed it was because she had missing teeth that her tongue was falling out, on Saturday we noticed a large lump on her gum she was took to the vet were he said it was a tumour, I can’t understand how this was not noticed in December as he seems to be very big for 3 months

    • Kevin J Groen says:

      That sounds exactly like my yorkie. He had some teeth removed in February 2020. He started lip smacking licking. The vet thought it was from increased saliva glind production. He died from carcinoma in his neck Nov 2020.

  4. Sara says:

    My dog had a mouth tumor removed. The vet said it was aggressive and would grow back. That was in Dec. it grew back in Jan. I started the drops from PetS Well-being. It is 4 months past initial RX and surgery. The tumor is large but doesn’t appear to be other places? He’s thin. The tomor bleeds at times. I just wonder if you know anything else I can give him?

    • Bianca hinojosa says:

      Can i ask what did you give your dog for the bleeding. My dog currently has the tumor in his moith. It bleeding starting to be a daily thing. Im at a loss on what to do. He still loves to eat and go for a walk.

  5. Michelle Burnett says:

    My one year old min pin has horrible breath, he’s had bad breath since we got him at 8 weeks old. Now I noticed he already has tarter buildup on his teeth and he only gets hard dog food.

    • Cindy says:

      Sal had horrible bad breath after a teeth cleaning and removal of 14 teeth We noticed noticed a mass on his upper lip. He’s a 10 year old Boston terrier.

      • KJ says:

        Can you tell me more about this… I’ve just found out my dog has oral cancer. He is 13 and is my absolute world. Vets are saying anywhere up to £3000, it’s not the cost I just don’t want to put him through horrific surgery if I don’t need to. He is eating, drinking, play fighting with his puppy brother. Jumps around when you pick his lead up, no different to how he has ever been.

  6. Jane Home says:

    My doggie of 13 yrs . Was diagnosed with oral cancer 14 months ago . We immediately put him on CBD powder . He is still alive , takes 4 small walks a day . Eats anything we give him . He looks forward to his mince Kong, after his daily medication … no surgery … just CBD powder , try it , what harm can it do

    • Rossi says:

      Can i ask what brand of CBD powder you use?

      • Diana says:

        It’s a sad day for us, we had to put our beloved fur baby down this morning. He was a 7 year old yorkie. 2 weeks ago I noticed a bump on his right jaw and I thought he might of had a snack stuck in his gum. But it started to get bigger and bigger and very tender to the touch. Took him to the vet 2 weeks ago and I as told it was an abscess. It turned out he had a type of very aggressive cancer when I took him back this morning. I’m devastated.

      • Carolina says:

        Hi. My 9 years old dog Brandy has 7 teeth removed this past Thursday . When they did that they found a small growth in the back of her gum. Biopsy will be ready in 5/7 days . How’s the chances that growth is malign ? I’m so scared .

      • Wendy says:

        My 12 yr old Portuguese water dog has a large tumor on her upper part of her mouth. They say it’s inoperable. Her breath is terrible and it smells up the house. When is it ok to euthanize a dog? She eats and seems to not be in too much pain although she is a much slower walker these days. Her quality of life isn’t great but if no one can stand to be by you, it really makes life less happy.

      • Marcy says:

        My dog 11 years old just diagnosed with an oral tumor under tongue towards front of mouth. Bad breath and a little bleeding. The dentist is doing a biopsy to see if it is benign or malignant. I pray it’s benign and then we will consider surgery although it seems very scarey

    • Steve says:

      Can you share the CBD powder that you are using ? Thank you

    • Cherl Thorne-Fielder says:

      what kind of cbd powder, I googled that and hemp oil comes up, is that the same!?

  7. Kevin J Groen says:

    That sounds exactly like my yorkie. He had some teeth removed in February 2020. He started lip smacking licking. The vet thought it was from increased saliva glind production. He died from carcinoma in his neck Nov 2020.

  8. Jo says:

    My dog is from battasea he has bad teeth now he has a lump in his mouth I’m on benefits and can’t afford vets they wouldn’t take insurance said Cos didn’t no how old I got I’ll and can’t work my benefits won’t help and ideas pleas

  9. Joe Coxon says:

    How is your dog? My dog more than likely has a tumor in his mouth. Reaching out for assistance. Thanks

  10. Isabel says:

    My 3.5 year old dog has a tumor on mouth, the vet said it similar to epulis but it doesn’t look benign. She gave antibiotics to see if it will go away, if not she has surgery in 3 weeks. Vet did not do a blood test. Should I get a second opinion?

    • Sherylyn says:

      I use pet well being products too but recently took him off. 8ts just prolonging our agony although I’m very appreciative for what it did do. Their products are excellent. I just couldn’t afford biopsies and surgeries not even chemotherapy. I’m poor and live off 1000 a month. But my rent is low so I gave him all my money I had. He has been in a wellness program every since I’ve had him for 5 years he’s 16 years old now and wants to live which I can’t bear to put him down. He gets codeine every 6 hours unless sleeping. He eats ok and drinks water and poopies everyday. I love him and that’s our story of him having oral cancer.

  11. Brenda Iten says:

    My Jack Russell gets dizzy. Has that happened to anyone else’s dog?

  12. Sharon Burrell says:

    About 3 months ago I noticed blood coming from my 80 lb bull mastiffs mouth. I took him to a vet who came out to the car and looked at it and said yeah, its cancer?? He said it would have to be cut out along with part of the jaw and it would come back and have to be done again until he passed away. Well so far he still is very energetic, hasn’t lost any weight and haven’t seen any bleeding lately. I opted to not have all that done. Im wondering if this was possibly just and abscessed tooth.

  13. Caroline says:

    My 11 year old husky has a growth in his mouth and we are waiting on biopsy results. He is a rescue and been through a massive operation on both his legs not that long ago. Reading up on mass removal it sounds so bad even though there is a good outcome. I am just not sure if i should put him through another big op or let him go. My heart is breaking

    • Dustin says:

      I have a dog who has a cancerous oral tumor that isn’t operable. And the smell is rancid and really hard to deal with. Are there any suggestions on something I can do to help with the smell??? It’s a ver challenging situation and I feel awful for him. But it’s hard for other people to even want to pet him because it smells so bad. Any suggestions would be hugely appreciated! I’ve tried everything I could think of. Thank you.

    • Sherylyn says:

      If you can save him please do. If I could save mines I certainly would not hesitate to do so.

  14. Ysaias says:

    We took out 13 year old Chihuahua to get her teeth cleaned because her breath was horrible. They found a dime size tumor on the back of her tongue. They said said they could do surgery but it would come back. They also said they wouldn’t know how much of her tongue they would have to remove. We tried holistic meds to see if it would help. To make a long story short. We put out sweet Abby girl down 10 months later. The tumor was twice the size and she was in lots of pain. She seem to be getting along fine then one day she quit eating and drinking and would not come out of her kennel. We took her to be put to sleep. We are so heart broken. Have your dogs mouth check often. Don’t fee regret like we are. RIP Abby girl.

  15. Jennifer Webster says:

    My 8 yr old mastiffs jowls are bleeding bright blood on both sides, & has for a week. He’s still eating & drinking ok, but has a little smell on his breath, I just figure it’s the smell of blood. He’s going to the vet tomorrow. I’ve been told it’s possibly Dermatitis or maybe even jaw cancer, any thoughts??

  16. Sherylyn says:

    The best thing is listen to the vet. And many of us on here like myself can’t afford the treatments. So I give my baby codeine and feed him well and sleep with him next to me every night. That’s all I can do. Also, make sure to keep him in a wellness program. At least he’ll get the bare minimum in care.

  17. Nayda says:

    My Yorkie has malignant oral cancer on lower jaw. Smells and is black and beginning to hurt when I try to clean inside mouth w QTip. I see here, like many, she’s walking, eating ok. She’s having trouble sleeping. Any ideas?

  18. Deborah says:

    I brought my dog to the vet thinking her teeth where bad as her breath was horrid. The vet says she has a very bad oral cancer, and in extreme pain. Even though she does not show any signs of pain. The vet told me that it takes a lot for a dog to show pain at all. I was in total shock, not expecting this diagnosis. I was not thinking very clearly, and said I would take her home that day, which was a Friday and have her put down, on Monday. She was given a strong pain medication shot that lasts 24 hours, and send me home with 3 more. I should of put her down immediately. Oral cancer is a very painful disease, in my opinion, because of this I would not prolong a pets life. As a animal does not show any pain until its very very serious. But that’s just my view on the subject.

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