Breast Cancer Signs in Dogs: What to Look For and How to Think About Mammary Cancer
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
Updated: May 15th, 2024
Summary
Finding a lump on your dog’s breast is not good: Learn how to examine your dog for breast cancer and when to head to the veterinarian.
Breast cancer … in dogs? Can dogs even get breast cancer? Yes, they do. We don’t call it by the same name; in dogs, we call it mammary cancer. But because the mammary gland is the bulk of the breast, and the disease is very similar, mammary cancer is, in fact, dog breast cancer.
Thankfully, breast cancer in dogs is not as aggressive as breast cancer usually is in humans … but it’s serious, nonetheless. For a full discussion of breast cancer, including its warning signs, treatment, and special diet considerations, please see chapter 31, which starts on page 320 of The Dog Cancer Survival Guide.
Signs of Breast Cancer in Dogs
Signs of breast cancer in dogs include the following:
- small nodules (bumps) within the mammary tissue that feel like little BBs under your fingers
- larger nodules within the mammary tissue, still under the skin
- bloody discharge from the nipple
- straw-colored discharge from the nipple
- pus-like discharge from the nipple
- larger, deeper growths in the mammary tissue that protrude visibly and can be seen as lumps
Want to learn more about mammary tumors and how to treat them? Get the Dog Cancer Survival Guide, and flip to Chapter 31
Spaying and Breast Cancer
Veterinarians often advocate early spay for females because it can prevent breast cancer later on. This is usually done before the first heat comes at about six months.
And it’s true: female dogs who have been surgically sterilized before their first heat, which is usually around 6 months of age, usually live essentially free of breast cancer.
As the spay age increases, this protection drops.
Sounds good, right? Well, yes, as far as breast cancer goes. But you should also know this: early spay and neuter before the first heat is associated with increased risks of other types of cancer. Those other types include the very aggressive osteosarcoma and transitional cell carcinoma.
This is why we debate whether early spays help avoid cancer. The evidence is mixed. Early spays almost completely eliminate breast cancer, which is nice. But early spays INCREASE the risk of more aggressive cancers.
Found a Lump on Your Dog’s Breast? Get It Checked.
The most critical thing to remember is that if you have a female dog who has a bump in the area around the teat (nipple), please get it checked.
Many of these growths are life-threatening. And if you have a female dog who is not spayed (intact), or was spayed later in life (at more than 6 months of age), examination of the mammary tissue of your dog may be a lifesaver.
How To Give Your Dog a Home Breast Exam
A breast exam in dogs? Yes, you heard it here first. You should absolutely examine your dog, especially if she is intact or spayed late.
How do you do it?
First, you have to be able to see and feel her belly. Many dogs already like to lay on their sides or back. If your dog “gives belly,” you can do her exam then … but even dogs who won’t roll over can still be examined.
Whether giving belly or standing up, here’s what you do.
First, find the mammary glands. Dogs normally have ten, two rows of 5 going down the length of the body, one on the left and one on the right. If your dog has an extra teat or a missing teat, or if they are not perfectly aligned from left to right, don’t worry. Variations are normal!
Second, use your fingers to “see” as well as feel, as instructed below. There are two separate techniques to use — so don’t skip these steps.
- To make sure your dog is comfortable, try doing this with two hands, one on the left chain and the other on the right chain.
- Keep your fingers flat and use the pads of your fingertips to “fan” through the mammary tissue up and down the torso, from the head to tail. Start on the first teat on both sides and work down toward the last teat on both sides, feeling for “blips” or bumps under your fingertips.
- Still keeping your fingers flat, fan your fingers left to right, from the first set of teats to the last. You are still looking for those little blips or bumps.
- Next, use the second technique, which is to gently press the mammary tissue to look for deeper bumps or lumps. On each teat, gently gather the mammary tissue between your thumb on one side and your index and middle finger on the other. Keep in mind that this could be sensitive tissue, so be gentle! Gently roll the tissue with your thumb as your fingers hold the other side. Move your thumb in a circular motion and feel for blips and bumps between your fingers.
- Remember, you are looking for little lumps and nodules that feel different from the surrounding mammary glands.
- Any area that is hard or different is worth having a veterinarian take a look at.
- If you can see pus, blood, or any other abnormality on the mammary tissue, get it looked at.
How often to do an examination like this on your dog? I suggest every month or so for female dogs above the age of 7 years.
Even if your dog had an early spay, do a breast exam every once in a while for your own peace of mind. It’s well worth the few minutes.
Treating Breast Cancer in Dogs
Breast cancer in dogs is best treated with a combination of different Full Spectrum steps. In my patients, I use surgery, dietary changes, Apocaps, deliberate efforts to increase life quality, reduction in body fat (a risk factor for mammary cancer), immune-boosting and anti-metastatic supplements, touch therapies, and more. As a rule, this cancer does not respond very well to chemotherapy.
Best,
Dr D
Spay/neuter and the association with cancer in dogs: part one
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
Have diagnosis, just need info: Hi Dr. Dressler,
My chi has breast cancer that has matastisized and is terminal. She came from a puppy mill and it was obvious that her life before me was a bad one. She already had a lump when I brought her home. Her hips, shoulders, and knees are in bad shape & painful. She actually walks sideways most of the time. Watching her walk is painful; I can’t imagine how it feels to her. I didn’t want a chi but I couldn’t leave her there to be bred with her dad, (the owners hubby let that info slip). It took 3 months just to be able to pet her. She couldn’t stand a large room. I sat in the bathroom floor for hours and just talked softly to her. I have owned chihuahua’s before and was familiar with their charateristics. Of course, I fell in love with her and she is now spoiled rotten and happy–and warm. She loves and trusts no one but me. Her eyes never leave me no matter where we are or who holds her. The cancer is too advanced to warrant the pain of surgery or chemo. She would die anyway. She developes cysts that are painful but usually clear up with antibiotics in a few days. She has developed a lump on the left side of her back with swelling that runs around to her lower abdomen. It is harder than the other cysts. Of course, this developed 4 or 5 days after a vet visit. I am not looking for treatment at this point, (it is too late), but I would like to know what to expect as the stages progress toward her final days. Where does the cancer usually go, what will happen with her when the time is near, how bad is she going to get when she will no longer get better from being sick or in pain. Will it go to the lungs, kidneys, brain, or where. Mom had breast cancer that ended with lung cancer, also went to stomach and kidneys before she died. A friends went to her brain before she died. Rose, (the chi), already has hard, loud breathing. I guess what I am looking for is a sort of road map for the travels this cancer is likely to take and the symptoms I might see as it goes through. I don’t want to call the vet again because I spent a few hours there a few months ago having my beloved Boxer put to sleep, (cardio myopathy), and everyone there was crying over her. They really love the animals they care for. I am sure they are dreading the final time I take Rose in. I just want to know what to expect until that time comes. Thank you.
Dear Shae,
Sorry this is so advanced. How did this happen that it got so bad?
I am sorry but this is a question for your veterinarian. Type of cancer within the breast dictates where they go and how they behave. Some spread to the lungs and their is coughing, weight loss, labored breathing, less energy. Some don’t spread except to the surrounding area and these become large and often inflamed and painful. Time again depends on cancer type but without treatment often there is only months in advanced cases.
I would be at least thinking of diet and supplements here which are low toxicity but can help.
These are well outlined in the Guide.
All my best
Dr D
HI
I think my labrador has a breast cancer. the area around one of her nipples is swollen. when i squeezed the nipple a pus-type liquid came out. i asked my father and he said that its normal when she is on heat. but he says that about everything to do with pets. i really want to take her to the vet but my father doesnt because its too expensive. please help!!!
she is 8 years old and has had one litter of puppies when she was about 4. i hope this helps her.
THANKYOU!!!!!
Dear Bella
i’d have to go with your opinion to get it checked out at the vets. Might be nothing, but might be something. Here are some posts for your father:
https://www.dogcancerblog.com/blog/the-cost-of-my-dogs-life-part-1/
https://www.dogcancerblog.com/blog/the-cost-of-my-dogs-life-part-2/
I hope this helps
D
my female dog is 8yrs. old . she is a golden retriever and her name is baily. she has breast cancer. lately she has had greyish diarrhea. is this related to the cancer ?
Dear Esther,
I a sorry to hear about your Baily.
Diarrhea is a common problem in dogs, and since there are so many causes of diarrhea, it is very difficult to say the cause. Please have your vet work this up.
Best
Dr D
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Thank you for this article. I have recently noticed my female Chihuahua’s two mammary glands (the one’s closest to the groin) seem a bit firmer and slightly larger than the others. I felt them and they feel firm and one feels like a ball but they do not seem to cause her pain to the touch. I am concerned though because she is 4 years old and i have not got her spayed. ( I intend to soon, i have just found out that getting her spayed protects her from breast cancer. ) I was wondering if you think i should be concerned about her glands? They are not flat anymore and i was wondering if that was because of her adult development or because something is wrong. Could you please give me your opinion.
Dear Sweetpea,
I am sorry but I cannot diagnose anything on-line. Please have a licensed vet examine your dog.
Best,
Dr D
Hi,
My 4 year old bitch had puppies 9 weeks ago . She has started producing bloody discharge from the bottom two nipples. She has a temperature of 103.6 and is on synulox antibiotics after seeing a vet . The vet says she suspects she has mastitis however the teat is not swollen only abit lumpy but apart from that its flat. I noticed bloody discharge is a sign of breast cancer do you think I should be more concerned and question her diagnosis as mastitis, as I have had mastitis in my breeding bitches before and it has always occured afew weeks into feeding pups and they have been big swollen and sort of ropey feeling. This is nothing like that the teat looks normal at a quick glance it is flat but is abit bumpy but not at all red or swollen ?
Please help
Thanks
Kerrie
Sorry I just realized that I forgot to add the word NOT disproven in the Oncologists thoughts. That would make better sense. 🙂
Hi Dr Dressler,
Well I went ahead and got the thoracotomy and removal of the lymph node done on my girl “Miura” who is an just turned 8 year old doberman by the way. She looks and acts 6 ! It was a very scarey time but she was strong and the tube was pulled in 24 hours and she went home on the 3rd day. ( she wanted out of there bad! ) They also removed the mammary tumours. This was all done after consulting with the oncologist and specialty surgeon. They were referred by my regular vet.
The biospy results came back : Morphologic diagnosis #1 Pulmonary Papillary Adenocarcinoma # 2 lymphoid hyperplasia , hilar lymph node #3 multiple benign mixed mamary tumors,left second gland. #4 diffuse lobular hyperplasia and mltifocal dysplasia, left second and fourth glands. # 5 low grade mastitis both glands.
His comment ” The tumor in the lung is circumscribed and relatively well differentiated. The decision to call it an adenocarcinoma rather than a papillary adenoma is based on cytologic atypia and loss of nuclear polarity as well as the finding of low numbers of mitotic figures. I did not see evidence of invasive growth, invasion of lymphatics and the hilar lymph node was negative for metastatic disease. I prefer to be optimistic and would suggest a cautiously favorable prognosis. I think a series of radiographs over the next several months is in order. Both glands (mammary) had innumerable foci of atypical hyperplasia and dysplasia which can be considered pre- neoplastic and it could be argued that some of the foci represent in situ carcinomas.
The oncologist seemed very optimistic and recommended chemo treatment alternating every 3 weeks on 2 different drugs vinorelbine and carboplatin for min 4 treatments to 6 . She started Oct 28,10 and will have a CBC in 10 days
What are your thoughts?
I have read your guide and it has helped me alot. She is on the cancer diet started before surgery. I am abit confused though because she is now on chemo what to safely give her ie apocaps etc and what to wait for until after the chemo is done ie omega 3 .Asking the oncologist she remained very “Neutral” Saying nothing has every been proven on dogs but also in theory disproven .
What would be my next step ? What supplement would you recommend while on chemo ?
Sincerely ,
Norine
Hello Dr D.
My dog was recently given a diagnosis of having a primary lung tumor.
Unfortunately due to the location the oncologist said that it was too difficult to do a aspiration of it . Surgery was deemed the only option to beable to do a biopsy of it and the lymph node. An ultra sound was done on her other organs and showed no signs of metastasis. This all came about as a result of finding 3 BB sized tumors in her mammaries upon a typical physical. I had requested an x-ray “before” surgery to rule out any spread. That’s when the Dr found the tumor on her lung lobe. She has no symptoms at present and the Dr feels based on the x-rays that this can be removed with heathy cells dividing it cleanly ?? He obviously won’t know for sure until he gets in there to see any evidence of metastasis . I didn’t see anything about lung cancer and am wondering what your thoughts were on this subject . Also the tumours on her breasts should they be removed at the same time as I am afraid they could be linked even though I was given the 50/50/50 rule by the Dr. Or should I wait to see the biopsy results of the lung first ? Due to longer time under and longer post operative care and pain I am a bit afraid to take that step. I want to do what is best for my dog? What would be your recommendation?
Thank-you,
Norin e
Dear Norine,
a nodule in the lung does not a cancer make, not by definition anyway. Consult with your vet/onc, but you might consider getting the mammary masses removed and biopsied to see whether the odds of this being a met are high or if those mammary lumps are benign.
I would take some time to get and read the Guide
too- I think it will help you with some of these decisions.
Best,
Dr D
Dr. D. I publish a newsletter for the Sussex Spaniel Club of America. Your article on Breast cancer in dogs is interesting and I think would be of interest to our members. In fact we have a member who recently loos a bitch to the disease. May I reprint this article in the October issue of the Scentinel? I could send you a copy of the newsletter if you like. Thank you.
Barb Jones
Dear Barb,
yes, I would be honored to have the article in your newsletter. And of course I would enjoy reading a copy! Send it to my hospital!
Best,
D