Skip to main content
AdviceDogsHealth AdvicePetsUncategorized

Breast Cancer In Dogs

By October 13, 2023 November 13th, 2023 No Comments

Can Dogs Get Breast Cancer?

Sadly, yes — one in four dogs will develop mammary tumors — but there’s an easy way to prevent them.

Closeup of white lab mix dog being pet under the chin by pet parent

You’ve heard of breast cancer in humans, but did you know that dogs can get it, too? Breast (mammary) cancer in dogs is common — in fact, it’s even more prevalent than in humans. The good news is, the disease can be treated successfully if caught early.

According to veterinarian Dr. Race Foster, the most common type of tumor in female dogs is the mammary tumor — especially in unspayed dogs between ages five and 10. One in four unspayed dogs is affected by breast cancer and approximately 50% are malignant. Some male dogs also develop breast cancer and sadly, their prognosis typically isn’t good, as the cancer is usually very aggressive.

Signs of Breast Cancer in Dogs

Similar to human breast cancer, mammary tumors in dogs can range in size. Breast tumors in dogs often grow quickly with an irregular shape. They can also cause bleeding and ulceration. Even if your dog has a tumor that doesn’t exhibit these signs, that does not mean they’re cancer-free. Small tumors that have been present for a while can suddenly grow aggressively. As with most other types of cancer, once malignant tumors in dogs start to grow, the cancerous cells can spread to other parts of the body.

Symptoms to look for are:

#1 – Unusual Odors

While “dog breath” is common, if you notice unusually foul odors coming from the mouth, nose or rectal area, it may be due to a tumor.

#2 – Bumps or Lumps On or Under the Skin

Get into the habit of checking your pet’s skin monthly. Don’t forget to check behind ears and around the face. Even if you find a very tiny lump or bump, cancer can grow very quickly. Any new lumps or bumps should not be ignored. If the bumps are bleeding or there is discharge, see a veterinarian immediately.

#3  Unusual Weight Loss

Unless you’ve put your pet on a diet, their weight should remain pretty consistent. Sudden weight loss is a cause for concern.

#4 – Appetite Changes

If your dog has lost interest in meal times, illness is likely the cause. Many health conditions cause appetite loss, and cancer is one of them.

#5 – Lethargy

Learn to tell the difference between a lazy dog and a lethargic one. You know your dog’s personality the best. If he doesn’t seem like himself and is spending more and more time sleeping, talk to your veterinarian.

#6 – Respiratory Problems

Dogs can get lung cancer, and some indicators could be coughing, wheezing, or shortness of breath after very little exercise.

#7 – Behavior Changes

Has your normally mellow dog been snapping? Is she spending more time away from you? She could be in pain. Also pay attention to how she is walking, eating and playing. If you notice any limping or struggling – it’s time to see the vet.

#8 – Open Sores

If your dog has an open sore or other wounds that aren’t healing properly, it could be because of a larger medical issue. Time to seek a professional opinion.

#9 – Vomiting and Diarrhea

If you notice that your dog is vomiting frequently, and/or has diarrhea, you should see your veterinarian, especially if it’s accompanied by any of these other symptoms. Also check your dog’s abdomen for bloating and distension (stomach swelling).

#10 – Pale Gums

Know what a healthy dog’s mouth looks like so you can tell when your canine’s isn’t. Very pale gums could mean blood loss, and cancer is one of many illnesses associated with this symptom.

If you find a lump on your dog, do not wait to go to the veterinarian. It’s always best to play it safe and have them examined by a professional. Even though half of all mammary tumors in dogs are benign, there’s no point in playing guessing games when it comes to your dog’s health.

Ask a Vet

Pet health question that’s not an emergency? Our vet team will answer over email within 48 hours. So, go ahead, ask us about weird poop, bad breath, and everything in between. You can also directly message the clinic using our new mobile through PetDesk.

Treatment for Breast Cancer in Dogs

A biopsy will determine the type of tumor your dog is dealing with. It will also determine the size of the tumor, whether the tumor has spread, and its history of rapid growth, which will narrow down treatment options.

Treatment of a malignant tumor usually involves surgery. Similar to breast cancer in humans, dogs will either have just the tumor removed or the entire mammary tissue along with lymph nodes. Dogs’ mammary glands are different from humans’ in that they’re outside the muscle, so surgery is not as invasive. However, chemotherapy and radiation in dogs has been to not be as successful as they are in humans.

Preventing Breast Cancer in Dogs

The best way to prevent breast cancer in female dogs is to spay them before they go into heat for the first time (just another benefit of spaying). By doing this, you’re practically eliminating the chances of your dog developing mammary cancer.

Approximately 50% of malignant mammary tumors in dogs have receptors for either estrogen or progesterone. Having these female hormones promotes the growth of these tumors. This means that spaying is important, even if a tumor has already developed. In one study, female dogs spayed at the time of their tumor removal (or in the two years prior to the tumor removal) lived 45% longer than those who remained unspayed.

Diet is also a factor in preventing breast cancer. Dogs fed a fatty diet or who are overweight have an increased risk of developing the disease.

Some cancer fighting foods that are dog safe are:

1. Apples

bunch apples for Cancer-Fighting Foods for Dogs by PetWell

Dietary fiber and polyphenol compounds from apples work with gut microbes to foster a setting that may help lower the risk of cancer.

They contain antiangiogenic properties that prevent the formation of new blood vessels from the walls of pre-existing blood vessels, which is a frequent mechanism for cancer to progress into tumors.

IMPORTANT: Be sure to remove the seeds and core. The seeds contain small amounts of toxins, not suitable for their digestion.

2. Blueberries

Berries are packed with plenty of phytochemicals and antioxidants, especially blueberries., The antioxidants work to protect cells against free radicals and inflammation, helping to prevent cancer. Also, they contain ellagic acid which helps block the metabolic pathways that can lead to cancer. As well as anthocyanins which reduce cell proliferation and inhibit tumor formation.

3. Broccoli

Rich in phytochemicals, vitamins, nutrients and antioxidants that fight cancer-causing free radicals. Also loaded with vitamins A, C, and D as well as a natural anti-inflammatory that collectively works to support immune health.

Glucosinates, abundant in broccoli are converted into biologically active substances with anti-cancer effects. They render carcinogens inactive, prevent DNA damage, and cause tumour cell death.

4. Carrots

Carrots contain pro-vitamin A, also known as beta-carotene. They are rich in phytochemicals, vitamins and minerals that support the immune system, aid digestion and fight cancer-causing free radicals.

5. Cruciferous Vegetables

Group shot of mixed Cruciferous Vegetables for cancer Fighting Foods for Dogs by PetWell

The cruciferous family include brussels sprouts, cauliflower, cabbage, rutabagas, kohlrabi, bok choy and turnips. They contain glucosinolates which are associated with decreased inflammation, lowering the risk of cancer.

According to recent studies, the chemicals in cruciferous vegetables “switch on” genes that suppress tumors, halt tumor growth and encourage cancer cells to self-destruct.

6. Kale

Research shows the carotenoids present in dark-green leafy vegetables like kale can work as antioxidants and strengthen the body’s natural defenses against free radicals.

These safeguards aid in preventing free radicals from damaging DNA, which can result in cancer. Kale contains antioxidants that work to prevent the synthesis of carcinogens in cells, which can lead to cancer.

7. Omega-3 Fatty Acids

Food that is rich in Omega 3 fatty acids as Cancer-Fighting Foods for Dogs by PetWell

Omega-3 fatty acids, found in fish and fish oil are well known for reducing inflammation and slowing down the growth of cancerous tumors. In addition to omega-3 fatty acids, vitamin D3 in fish and fish oil is an essential ingredient in cancer prevention.

High-quality proteins such as sardines, salmon, herring, cod, mackerel and shellfish are the best sources of Omega-3. These fish are also high in useful vitamins and minerals. Including calcium, phosphorus, iron, zinc, iodine, magnesium, and potassium.  Alternatively, you can use all-natural supplements that can be easily added to your dog’s bowl.

Omega-3 fatty acids have other benefits for your dog. It helps keep their coat shiny and prevents dry flaky skin. Plus it supports good gut health and joint health due to its powerful anti-inflammatory properties.

NOTE: If you chose to give your dog fish, make sure it’s cooked or freeze-dried.

Some raw fish contain dangerous parasites. For example, raw salmon poisoning is caused by rickettsia which uses a parasite fluke on the salmon as a host. This can be fatal for your dog.

8. Pumpkin

The pumpkin’s vivid orange color serves as a visible indicator of its high beta-carotene content which the body converts into vitamin A.

A powerful antioxidant that is essential for preventing cancer because it shields cells from the harm that free radicals can do. Beta-carotene can inhibit the progression of cancer and boost the enzymes that work to remove cancer-causing substances in the body..

9. Sweet Potatoes (Cooked)

bunch of sweet potatoes for Cancer-Fighting Foods for Dogs by PetWell

A special combination of vitamins and minerals found in sweet potatoes can help slow and prevent canine cancer. These include vitamins A, B6, C, E, and D. Plus the minerals iron, magnesium, potassium, folate, copper, and thiamine. And don’t forget the all-important carotenoids and beta-carotene,

IMPORTANT: Raw or dried sweet potatoes can cause digestive issues. Do not give your dog raw potatoes of any kind.

10. Turmeric

Turmeric contains curcumin, which is a powerful antioxidant and anti-inflammatory compound. It works as a cancer preventative by neutralizing free radicals in the body. Curcumin interferes with cancer development.  Combining coconut oil with turmeric can help the absorption of curcumin.

We hate the thought of our pups becoming ill, but being educated is key to keeping our dogs as healthy as possible. Everyone knows that the quicker cancer is found and diagnosed, the better the chances are of fighting it off and prolonging your dog’s life. While annual check-ups at the vet are important, a year between visits may prove to be just too long when it comes to fighting cancer.  Regardless of your dog’s age, be proactive by looking for early symptoms that could indicate cancer. Home assessments will help if you have any of the following breeds as a pet:




Yorkshire Terriers

Cocker Spaniels

Brittany Spaniels

English Setters

Boxer Dogs

Doberman Pinschers

Research in veterinary medicine continues, but to-date we still know little about which genes and mutations can lead to the development of mammary tumors in dogs. In human medicine, research has established a definite relationship between the BRCA gene (or breast cancer gene) and the development of breast cancer

The way malignant mammary tumors typically progress is entirely dependent on the type and size of the tumor(s), and whether metastasis has occurred. Larger tumors (those greater than 3 cm) and those with evidence of spread have a poor prognosis. Tumors smaller than 1 cm have a better prognosis. Detecting and treating these tumors when they are small and before spread has occurred will provide your dog with the best chance for long-term control.

If you have any concerns  call our office and schedule an exam as soon as possible. 417-876-5717

Mitchell Veterinary Clinic

Mitchell Veterinary Clinic

Providing veterinary care since 1995 like exams, vaccines, surgery, labs, dental, nutrition and more!

Leave a Reply