Breast Cancer in Dogs – Prevention and Treatment

You may not have thought about it, but dogs can get breast cancer, too. It is actually referred to as “mammary cancer” by veterinarians, and it is not uncommon in female dogs that have not been spayed. If breast cancer in dogs is caught in its early stages, there is a relatively high cure rate. For this reason, “breast” or mammary examinations should be a critical part of your female dog’s health regimen.

Dogs at High Risk for Breast Cancer

The risk for breast cancer in dogs increases with each heat cycle. The hormone processes that take place during each heat stimulate the mammary glands, and actually increase the risk of mammary cancer. For this reason, it is important to get your female dog spayed before her first heat cycle. Breast cancer in dogs rarely occurs in dogs that have been spayed prior to their first cycle.

breast cancer in dogs

As adorable as these puppies are, their mom has a higher risk of getting mammary cancer because she has not been spayed. Image credit: boxercab

Preventing Breast Cancer in Dogs

Spaying your dog early is the best defense against mammary cancer, but in lieu of that, regular mammary examinations should be performed. Visually inspect the breast area closely, and palpate the area around each nipple. Tumors will feel hard and will be static, meaning they will not move easily under the skin. These tumors tend to grow quickly however, and can be noticeably larger in just one month’s time. The more often you examine your dog, the more likely you’ll be able to identify any changes that occur. You should see your vet at the first sign of an abnormality.

breast cancer in dogs

This beautiful pup is about to fall asleep while getting a belly rub. This would be a great time to do a mammary gland exam. Image credit: David Whelan

Diagnosing Breast Cancer in Dogs

If mammary cancer is suspected, your vet will probably want to run additional tests to determine the nature of the mass, and whether or not it is malignant. About one-half of all mammary tumors in dogs are found to be malignant. Diagnostic tests might include blood tests, x-rays, ultrasounds or biopsies.

Treating for Breast Cancer in Dogs

If your dog has been diagnosed with mammary cancer and is young and healthy enough, surgery may be the best treatment regimen. If performed early enough, surgery has a 50 percent cure rate. Surgical removal of cancerous mammary tumors in dogs is less complicated and easier to recover from than in humans, so as long as they are detected early, your dog will have a good prognosis for recovery. Chemotherapy and radiation therapy are not used widely for breast cancer in dogs, so surgery is often the best option.

breast cancer in dogs

If your dog is diagnosed with mammary cancer, surgery may be the best treatment option. Image credit: Staff Sgt. Stephanie Rubi

Although breast cancer in dogs is a serious health threat, it is one of the most easily preventable cancers in dogs. Dogs that are spayed prior to their first heat only have a 0.05 percent chance of developing the disease, but that probability increases with each heat. It is therefore imperative that you spay your dog as early as possible. This is the best prevention available.


  1. Interesting article. I would have thought the opposite. Use an organ the way it was intended and it stays healthy. Haven had a girl dog in a while will share with friends though!

    • I know. sometimes I feel it’s overwhelming to think of all the things that can happen to our pups’ health. Spaying before the first heat is the key to prevention in this case.

  2. This is great information. I worked at a vet for 7 years, and the thing that most vets recommend to helpt prevent breast cancer is to have your female dog spayed. It drastically reduces the likelihood that she’ll get cancer.

    • Thanks, Ben. I am finding that most people don’t realize mammary cancer is a risk. Spaying early may save a dog’s life.

  3. I honestly never thought about the fact dogs could get breast cancer, but it makes perfect sense! Our dog is a male, but he goes for his annual physicals each year (plus whatever other appointments his allergies require) and so far so good. I’ll pass this along though, I had no idea!

  4. I didn’t realize that dogs could get breast cancer too, although it does make sense that it is possible. Definitely something to be aware of as a pet owner.

  5. I had no idea that a dogs chances of breast cancer increased with each heat cycle. It is just another reason to have your pets spayed. It is always so sad when a pet gets sick.

    • Claudia – Spaying and neutering are the answers in a lot of preventative dog health issues. Thank you for reading and taking the time to comment.

  6. I honestly never thought about this happening to a dog before! I always look forward to your tips and advice. As a pet lover and “owner” I love keeping up on these things so I have the edge on the warning signs!

  7. I’ve never thought about this before, this post is an eye opener and I’m going to make sure that I check Ella from time to time. I don’t want her to experience the pain of having breast cancer. Thank you so much for this post.

    • AnnMarie – I’m finding that many people were not aware that dogs could get mammary cancer. The more information we have, the better we are able to keep our pets happy and healthy.

    • Rose – I hope you’ll keep coming back to read more as we continue to share important news in the pet and animal world.

  8. This was actually news to me! I had no idea that dogs could get breast cancer! This post really opened my eyes and I am going to make sure that I check my 10 year old female frequently now! Thank you so much.

  9. This is great information and so important! I think the fact that prevention can be done by getting them spayed early is really great! That gives a lot of dogs a great chance of never having to do through this.

    • So true, Emily. And that’s not to mention all the other benefits that come from spaying your pets before their first heat.

  10. We’re actually scheduling our fur babies to be spayed and neutered within this month. Now that they are out of the “puppy” months. :)It is always great to look out for their health too — after all, they are family.

  11. This was a very interesting read. My kids and I had a discussion about it. They are familiar with breast cancer because both of their grandmothers were survivors.

    This was a teachable moment.

  12. I’ve never thought about dogs having cancer until recently. My mom’s male dog is dying from cancer. It’s a horrible thing for dogs just like for people. Thank you for sharing this.

    • Shannon – I’m so sorry to hear about your mom’s pup. It is incredibly hard to lose something we love so much.

  13. This is really sad dogs like people are affected by this terrible C. I hope that this awareness you are raising can help some dog owners to cope and work through this cancer scare.

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