Breast Cancer in Dogs

Understanding and Successfully Treating Canine Breast Cancer

Mammary cancer is one of the more common types of cancer found in older female dogs but has been on the rise in younger dogs in recent years.

If detected early, it can often be successfully treated by surgical removal. Relapse is not uncommon especially when dealing with certain types of tumors that are difficult to completely remove, such as sarcomas. For this reason, ongoing holistic diet treatments offer the highest chance at maintaining remission.

Breast cancer is rarely found in dogs that have been spayed within 2 years of age. For this reason it’s considered one of the most preventable types of dog cancer.

 Dog CancerCanine mammary cancer can occur in any of the glands, but is most common in the 4th and 5th glands, which are the closest to the hind legs.

Mammary cancer tumors in dogs are can be small, simple benign nodules or large, aggressive, metastatic growths. It’s also possible for benign tumors to become malignant and spread through the lymphatic system, so it’s extremely important to have a thorough examination if any abnormality is noticed.

Canine mammary cancer can and does develop in any of the 8-10 breast of a female dog, however the breasts closest to the hind legs are where they are most commonly found.

It’s uncommon for mammary tumors to develop in male dogs, but it can happen. Usually in these cases, the tumors are very aggressive and have a much worse prognosis, especially if using conventional methods alone.

 Dog CancerMammary cancer spreads to the rest of the dog’s body through the release of individual cancer cells from the various tumors into the lymphatic system.

Main Causes for Breast Cancer in Dogs

Though there is a link between the female reproductive hormone progesterones and mammary tumors, this should not be mistaken as the cause of the disease. It’s suspected that the hormones promote cellular growth, which then increases the number of cells that may be susceptible to malignant transformation.

The actual causes for the immune dysfunction and development of the disease are unclear, but improper diet and exposure to certain chemicals are considered main factors.


A biopsy is needed to accurately determine the the type of tumor and severity of the disease. Often, the tumor is removed during this process.

Malignant tumors can metastasize and spread to the lungs or surrounding lymph nodes, so a chest x-ray and physical inspection of the lymph nodes may be performed with certain types of mmammarytumors.

 Dog CancerCertain types of cancers such as sarcomas, are difficult to completely remove, and without ongoing treatment, the tumors are likely to return.


If detected early and tumors surgically removed, most malignant mammary cancer cases have around a 50% chance of successfully eliminating the disease. Complete removal of some types of tumors, such as sarcomas, can be difficult resulting in the tumor returning to the same area.

Relapse or developing mammary cancer in another breast is not uncommon.

Canine Breast Cancer Symptoms

About half the cases of mammary tumors in dogs are malignant and often show rapid growth spurts, while benign growths are often more slow growing.

  • Firm attachment to skin or underlying tissue
  • Bleeding and ulceration
  • Irregular shape

Spaying and Prevention

Spaying has shown to lower hormones such as estrogen and progesterone. This in turn drastically reduce the chance of a female dog developing mammary cancer.

Females dogs spayed prior to their first heat cycle very rarely develop mammary cancer is less than 1%. In contrast, female dogs spayed after their second heat have 25% chance of developing mammary cancer.

Types of Malignant Tumors found in Dogs

Single tumors that possess more than one kind of cancerous cell is referred to as a “benign mixed mammary tumor”.  These are rare occurrences where the tumor consists of both glandular and connective tissue.

  • Tubular adenocarcinomas
  • Papillary adenocarcinomas
  • Papillary cystic adenocarcinomas
  • Solid Carcinomas
  • Anaplastic Carcinomas
  • Anaplastic Carcinomas
  • Osteosarcoma
  • Fibrosarcomas,
  • Malignant mixed tumors

Conventional Treatments for Breast Cancer in Dogs

Surgical removal is the most common type of procedure performed, and this can often be successful in completely eliminating the disease. However this alone does not deter another case or a relapse from occurring.

Occasionally, chemotherapy such as  Mitoxantron (Novantrone™), Adriamycin or Cytoxan is administered to aid in the prevention of metastases to the lungs. 

Chemoprevention supplements such as Inositol hexaphosphate, and 1-3-beta glucan may be recommend for the prevention of tumors reoccuring on dogs that are considered to be more predisposed.

Tamoxifen (a drug often given to women with breast cancer)  has shown no positive clinical results at this point for treating advanced mammary cancer in dogs.

Conventional treatments for mammary cancer in dogs are considered to be more successful than other types of canine cancer, however they’re still only a little more than 50% successful when used by themselves.

Holistic Treatments for Breast Cancer in Dogs

Holistic  Veterinarians and health practitioners seem to have a little better understanding of the philosophy of “treating the patient” not just the disease. They tend take into account the unique circumstances of that particular dog, as well as what’s leading to the illness or disease.

A tumor or any disease is the result of an underlying issue (the cause). That issue needs to be addressed in order achieve and maintain remission. This along with promoting the body’s ability to heal itself, are the main aspects of holistic approaches.

It’s important to understand that many conventional treatments do have some undeniable benefits, but they also have their limitations. To fully realize their potential, they must combined with a holistic approach that promotes health as well. Otherwise, the initial cause and the bodies ability to heal itself are constantly working against the treatment.

The body has a remarkable ability to heal itself. In fact, it’s only the body and the immune system that can heal itself. This fundamental aspect of nature must be recognized and honored by promoting its ability to heal. Only then do we have the  highest chance at attaining and maintaining remission.

The proper diet with powerful immune boosting herbs and cancer fighting supplements offer the best to address and alleviate the underlying causes, while promoting cell recovery. This is extremely important when dealing with the possible relapse of breast cancer in dogs.

Just as the improper diet can cause complications that lead to disease, a holistic cancer diet treatment can work to help reverse those issues.

Is it a Case of Faulty Genes?

In the vast majority of cases, absolutely not. Some types of cancer are more common it certain breeds as canine mammary cancer is more prevalent in: poodles, Brittany spaniels, English setters, Pointers, Fox Terriers, Boston Terriers and Cocker Spaniels. However, it’s important to understand that predisposed does not mean predetermined! Genetics are a factor, but there are many other factors as well.

Many dogs have these same “weak links” and go on to live a healthy full lives, while some unfortunately do not. Genes are merely blueprints, and it’s how well these these blueprints are properly built upon and maintained that makes the difference.

For cancer, or any disease to develop, a dysfunction in the immune system must be present. So by addressing this area, we can greatly reduce illness regardless of what genetic challenges a certain breed has.

All that being said, when a breed is more predisposed, this simply means that when something is challenging the immune system, this is the weakest link that we often find the effects first.

External factors such as dietary complications and toxins are a main factor in affecting the digestive tract and immune system, which are directly linked. This intern allows for the cells to be altered and cancer to develop.