Your Guide to Mammary Cancer in Dogs

Mammary cancer in dogs isn’t something you think about when your dog is a puppy. Now that our dogs are getting older, I think we tend to sit up and pay attention when we discover new lumps or bumps.

If you’re worried about a new lump on your dog, please make an appointment and get her to the vet as soon as possible. 

If it is a tumor, it will need to be aspirated or biopsied to get an accurate diagnosis.  Dogs diagnosed with mammary cancer have a 50/50 chance of the tumor being benign or malignant.

By the time you’re finished reading this post, you should have a better understanding of mammary cancer in dogs, how a prognosis is made, and the treatment options available.

According to the Veterinary Cancer Group, mammary tumors are reported to occur in approximately 2 out of 1000 female dogs.
But first…please read my privacy policy and disclaimer. I am not a veterinarian and I never suggest taking any dog health advice unless it comes directly from the mouth of a licensed veterinarian. Also, there are affiliate links on this page. All that means is that if you click on an ad, I will get a small commission. It won’t cost you a cent though.

The Big Question:  What is the Prognosis for Mammary Cancer in Dogs?

Canine mammary cancer has a 50/50 chance of being benign or malignant.  Dogs spayed before six months of age stand the best chance against mammary cancer. 

Once a lump has been removed and analyzed, your veterinarian will be able to determine the grade and stage of the tumor. This system is useful in determining whether the tumor is malignant (spreading) and how advanced it is.  In this case, you want the lowest grade possible for the best outcome.

Grade I:     At this level, the tumor is benign (not cancerous) and has not spread to other parts of the body. This type has the greatest chance of survival, assuming that the entire tumor is successfully removed.

Grade II:   The tumor’s position is deeper and more likely to spread.   Don’t panic, because it may not have spread yet.  At grade II, the chance of the tumor being cancerous is greater.

Grade III:  This is not the grade you want your dog to get.  The tumor is likely aggressive and will require a lot more treatment including surgery, radiation therapy, and chemotherapy.  Note: The veterinarian/surgeon will determine the best treatment options.

After a grade has been established, the next step is to assign a stage.  Stages 0 through 3 have different outcomes as you’ll see below:

Staging Process to Determine How Long a Dog Can/Will Live with Mammary Cancer

Stage 0:   At this stage, no lymph nodes are involved which means the cancer has not begun to spread.

Stage I:   Stage 1 means that the tumor has not spread yet.

Stage II:  Stage II is getting a little more serious and probably involves the lymph nodes.  The veterinarian will need to determine how many lymph nodes are affected and where.  The image below shows you where to find the lymph nodes in your dog’s body.

Stage III:  Multiple tumors with or without lymph node involvement.  This is where things get serious. 

The Science Behind the Spay

Mammary cancer in dogs is more common in older dogs, and dogs who have either not been spayed, or spayed after the first heat. 

I’ve read that females should be spayed well before their first heat, and other reports suggesting that spaying should occur much closer to that 6 month mark. 

At the end of the day, you also have to factor that people are taking excellent care of their dogs these days and they are simply living longer.   So, in some cases, mammary cancer in dogs may develop simply because they have lived longer.

When a female dog is spayed, her reproductive system is completely removed, which eliminates the body’s need to produce estrogen and progesterone for the purposes of pregnancy.  High levels of these hormones are thought to increase the risk of mammary cancer in dogs.  It’s very possible that I don’t have that last statement entirely accurate, although the research I’ve done points to that.

Please remember that I am not a veterinarian.  I highly suggest taking your dog to see a licensed veterinarian if you suspect there is anything wrong.

FACT:  According to Fetch a Cure, approximately 6 million dogs in the US are diagnosed with cancer every year.  As stated above, our pets are living longer and that longer life exposes them to various types of cancers.  In addition, when dogs get cancer, the malignancy looks a lot like the human equivalent of the disease in that it spreads to the same organs.

Figuring it Out: A Canine Case-by-Case Study

You can’t tell by touching or palpating the lumps whether they are cancerous or not. The only way is to examine the tissue, which the veterinarian will do through a biopsy. In a biopsy, a small amount of tissue is removed and examined. 

In the best case scenario, all of the lumps are benign.  However, you could be faced with other scenarios including:

  1. Some of the lumps are benign, but some are also malignant, meaning the cancer may have spread to the lungs and lymph nodes.
  2. The lumps are all malignant and have likely spread to other parts of the body.
  3. All the lumps are benign.

The Most Important Thing is Not to Delay an Appointment with The Veterinarian

By using fine-needle aspiration, the veterinarian is able to take a small tissue sample for further evaluation. 

If there is more than one lump, all lumps must be tested because it is very possible for some to be benign (non-moving) and some to be malignant (moveable and likely to spread within the body). They are not all necessarily the same. In fact, there are different sub-types of malignant mammary cancer in dogs that will determine how aggressive the cancer actually is.

What Are The Signs and Symptoms of Mammary Cancer in Dogs?

In addition to seeing or feeling lumps in and around the breast tissue, you may also notice:

  • an unusual secretion draining from the nipple(s).
  • ulceration (in the case of large tumors)
  • inflammation
  • secondary infection which will leave your dog feeling under-the-weather

Again, the key is to be aware of what’s happening in your dog’s body and having any unusual lumps and bumps examined by a veterinarian. Even experienced veterinarians can (and have) missed the signs of cancerous tumors because they don’t always present the same way.

Everything I’ve read on the topic suggests that nobody (not even your veterinarian) can tell what a lump is just by looking at it. The only way to get an accurate diagnosis is through aspiration and/or removal of the lump.

Risk Factors for Mammary Cancer in Dogs

Female dogs not spayed are more likely to develop mammary cancer than any other dog.  The risk of a dog developing a mammary tumor is 0.5% if spayed before their first heat (approximately 6 months of age), 8% after their first heat, and 26% after their second heat.

If you suspect your dog might have mammary cancer, it’s important to understand that they are:

  • usually slow-growing
  • inflamed
  • moveable (implying a benign tumor)
  • affixed to skin or body wall

The motto used by veterinarian specialists is IF YOU SEE SOMETHING, DO SOMETHING.  That means if your dog has a mass that is the size of a pea (1 cm), and it’s been there a month, get it checked! 

Veterinarians should be aspirating more suspicious lumps rather than suggesting a wait-and-see approach.  In fact, this just happened to me. I brought my golden retriever in for a suspicious lump on her torso and was told it “looks like a fatty tumor”.  Then I was told to come back if the growth “doubled in size within a month”.

Let’s hope the veterinarian is right.

The following YouTube video shows you how to check your dog’s lymph nodes. However, please note that enlarged lymph nodes do not necessarily point to cancer and can mean any number of things.  If you suspect your dog does have enlarged lymph nodes, you should bring your dog to the vet.  The video explains it all!

Treatment is Not a Cure, But No Treatment is Deadly

Most mammary tumors are removed surgically, taking a wide margin to determine whether or not the cancer has spread. Chemotherapy is not recommended in dogs with mammary gland tumors.

The best course of action post-surgery is to maintain regular check-ups so that the veterinarian can intervene if any tumors come back. Mammary cancer in dogs is not necessarily a death sentence if the tumor is found early.

Quality of Life for Mammary Cancer in Dogs

If you get the worst-case scenario news, ask your doctor how surgery will affect your dog. You may have to decide if the post-surgery quality-of-life is worth the procedure. Some questions to ask the veterinarian might include:

  • Is my dog strong enough to undergo anesthesia?
  • What will my dog’s quality of life be after surgery?
  • What is a realistic life expectancy with the surgery?
  • What is a realistic life expectancy without the surgery?
  • Is my dog in pain?
  • How can I keep my dog as healthy as possible through this process?

Living With the Prognosis

I wish I could have given you a definitive answer to your question on how long a dog can live with mammary cancer. As you can see, the answer is a moving target that is dependent on a lot of different things.

You should know that new treatments are being studied all the time and researchers are getting closer to finding longer-term solutions for dogs with cancer. I realize that doesn’t help you much right now.

My best advice is to try and stay positive and work with your veterinarian to find the best possible treatment plan for your dog. Your beautiful dog is going to need a lot of care and love through this, and nobody is better equipped for that job than you are.

I want to wish you the best of luck as you go through this process. Please share your story with others so that everyone can benefit. Let us know what works and what doesn’t. What was your experience with the veterinarian and what challenges did you face?

Brain Tumors in Dogs

I want to be completely honest with you, dealing with brain tumors in dogs is not easy. If it were my dog facing that diagnosis, I would would want to know two things:

  1. Is there treatment and can my dog be cured?
  2. Can I afford the diagnostic tests and treatment?

What a horrible position to be in!

Yes, advancements in diagnoses and treatment plans are helping dogs to live longer lives with a better overall quality of life. Studies show that owners are increasingly opting for treatment to extend life rather than opting to euthanize.

If you are concerned about being able to afford the diagnostic tests and the recommended follow-up or palliative care, then read on.  Below, you will find 3 cost-effect strategies to help reduce the cost of treating brain tumors in dogs.

You Don’t Have to Compromise on Quality to Treat Brain Tumors in Dogs

The veterinarian will want to do a series of tests to definitely diagnosis the problem.  The more tests ordered, the more expensive the bill. Some tests could include:

  • Neurological exam.

This is done through a physical examination. The veterinarian will measure your dog’s reflexes, sensitivity to light, and condition of the pupils.

  • Blood tests

Results of blood work done will indicate whether the organs (kidney and liver, for example), are working properly.

A chest x-ray will show whether there is cancer in the lungs. Cancer in the lungs or elsewhere in the body could hint at a metastatic brain tumor.

You Have a Right To Explore All of Your Financial Options

If you are feeling guilty right now, I totally understand. It’s hard to talk money when your beloved dog is sick. After all, you don’t want people to think that you are trying to save a buck at the expense of your dog.

Don’t worry!  Your dog is part of your entire family, and you have to think of your family as a whole.  When shopping around for the best cost, keep the following tips in mind:

  • Do not just compare dollar-for-dollar; make sure you understand what treatment options are included in the final tally.
  • Pay attention to how you and your dog are treated.
  • Look for Board Certified Veterinarians

Some other options that you might not have considered include:


Neurology Services at Perdue University offer these trials as a way of testing new treatment methods. The benefit of taking advantage of a clinical trial is the significantly reduced cost, and the fact that your dog will be treated with the newest, cutting-edge technology.

Your dog will not be used as a guinea pig.  Treatments offered have been approved. Now, it’s just a matter of getting that real-world look at how the brain tumor responds to it.

As of this date, June 6, 2018, their website shows a clinical trial for dogs suspected of having a brain tumor. To gain acceptance for a clinical trial, certain processes have to be completed.  Requirements for acceptance are on the Purdue University website.

Take a look at this tweet. It appeared last year, but the information on clinical trials (see the link in the tweet) might be useful for you.

If you are interested in learning more, please visit their website. This is where you will find all of the frequently asked questions and contact information. Ask about the availability of subsidies!


Pet insurance plans are comprehensive and offer various price-points. It’s important to understand that insurance companies typically won’t accept your application if a diagnosis has already been made by a veterinarian.

There are several pet insurance companies and it is worth your while to explore them all.  If you cannot get insurance for your dog right now, it might be worth thinking about for any other animals you have.

I highly recommend checking out this excellent YouTube video. This man has gone through the experience and provides a lot of insight into what to expect.


The veterinarian is going to want to provide the best treatment options for your dog.  Comprehensive diagnosis enables the veterinarian to see the whole picture. When he/she has that information and is confident in the accuracy, a customized treatment plan can be established.

However, if you cannot afford it, the veterinarian would rather come to a reasonable compromise than have you leave with no treatment or diagnostic plan in place.

Signs and Symptoms of Brain Tumors in Dogs

Brain tumors in dogs are not always evident right away. Symptoms could be vague or non-existent in the early stages. Below is a comprehensive list of symptoms, and the type of brain tumor that could be causing them.

Please keep in mind that some of the symptoms noted below could also be related to an underlying or preexisting condition.

Brain tumors in dogs fall under one of two categories:

Primary Brain Tumors: The brain tumor developed on its own, within the brain, without other signs of cancer throughout the body.

Secondary Brain Tumors:  These tumors, called metastases, start as cancer in another part of the body then spread to the brain.

It is estimated that 1 in 4 dogs will develop neoplasia at some point. The definition of neoplasia: “uncontrolled, abnormal growth of cells or tissues in the body”.  Keep in mind that not all neoplasms are cancerous (malignant).  Malignant neoplasms are unpredictable and will invade other parts of the body.


The following are various types of tumors in dogs and their accompanying symptoms:


  • Circling

Circling can also be caused by Vestibular disease, liver disease, poisoning, stroke, infection.

  • Unusual Gait

Brain tumors grow and press on the brain. This intrusion affects cognitive function.

  • Aggression or change in personality

Dogs with diabetes, toxicity, infections, and pain may also exhibit this symptom.

Cerebral tumors will typically cause behavior changes, seizures, visual deficits and circling.


This type of tumor develops within the cells that produce cerebrospinal fluid in the ventricles of the brain.  It is not commonly seen.

  • Vomiting
  • Bradycardia
  • Blindness and/or dilated pupils that are not responsive to stimuli.


  • Head Tilting

Head tilting can be any number of things including an ear infection or a vestibular syndrome.  Your dog might tilt his or her head in response to a sound or command, but if you notice it happening continuously and frequently, you should bring the dog to the vet.

  • Uncoordinated Movements
  • Depression

Brain stem tumors will typically cause depression, head tilt, cranial nerve deficits, weakness and ataxia.

Sometimes seizures are idiopathic, meaning there is no known cause. Your dog might have one seizure, and never have another one.  Other causes of seizures in dogs include liver disease, kidney failure, toxins, or some other sort of brain trauma.

  “Primary nervous system tumors in dogs account for 60-80% of all such tumors reported in domesticated animals.” – source: UC Davis, Veterinary Medicine


This type of tumor occurs within the skull and accounts for about 10% of diagnoses made.

  • Hearing Loss

Mild to moderate hearing loss in dogs can also be caused by wax buildup, scar tissue from ear infections, and birth defects. It can also happen to older dogs.

  • Weakness
  • Inability to eat – no appetite


Cerebellar tumors occur at the back of the brain in the section that coordinates muscle control.

  • Loss of body movement controls (ataxia)
  • Head tilt
  • Circling
  • Vomiting (possibly)
  • Bradycardia (low heart rhythm)

As stated above, symptoms of a brain tumor might actually be something else entirely.  Remember to let the veterinarian know exactly what types of supplements and over-the-counter medications your dog is taking. Even “natural” supplements can interact with prescribed medications.

I want to offer you luck and an excellent prognosis for your dog. My heart goes out to you, and I hope you can find the best possible treatment options.

Thank you for reading this post. I hope you were able to get valuable, usable information from this post.

To learn more about me and what brings me to blogging, please check out this link. I am not a veterinarian. My intent is to resource quality, peer-reviewed, texts to deliver to smart dog owners like you.