Mammary Tumors in Dogs

Mammary tumors in dogs are lumps or swelling that occur in the breast glands. They are a common finding in female dogs that are not spayed or were spayed after the age of 2.

Studies have shown the risk of breast cancer in female dogs that are spayed before their first heat or before 6 months of age, is almost eliminated at 0.5%. The risk, however, becomes much higher (over 26%) in female dogs that are not spayed or spayed after the age of 2.

Unfortunately, the exact cause of developing breast tumors is not known but the contributing factors are believed to be hormones (estrogen or progesterone), obesity, and consuming high fat diets. (See Natural Cancer Cures below.) 

Mammary tumors in dogs are the second most common tumors found in female dogs (skin tumors being the most common).

The mammary glands are associated with the nipples and extend from the chest to the groin on both sides. A dog normally has five pair of mammary glands, each with its own nipple. It is therefore possible for tumors to occur in all 10 of the glands.

The most frequent occurrence of tumors found in female dogs however, are in the lower 2 pair of glands located in area of the abdomen and thigh.

note: Over 50% of female dogs diagnosed with mammary tumors will have more than one growth.

Benign vs Malignant Tumors

Benign tumors are usually slow growing, small nodules in well-defined or limited areas, like a small pea. Malignant tumors, on the other hand, can be similar to benign tumors but usually become more aggressive, growing larger more rapidly, having irregular borders and firmly attaching to skin or underlying tissue, perhaps becoming ulcerated or inflamed.

About 50% of mammary tumors in dogs are found to be malignant and 50% benign.

When tumors do arise in the breast tissue, they are usually easy to detect by gently palpating or feeling the mammary glands. On first appearance, they will feel like small pieces of pea gravel just under the skin. Since it is very difficult to determine the type of tumor based on just a physical inspection, a biopsy is performed.

By performing a biopsy (removal and analysis of cells and tissue), the type of tumor and how invasive it is can be identified so a treatment plan can be developed. With early detection and prompt treatment, even some of the more serious tumors can be successfully treated.

Photo courtesy of Wikipedia

Mammary tumor in a fourteen year old Labrador Retriever. The tumor is about eight centimeters in length. It was confirmed to be a carcinoma on histopathology.

Treatment and Prevention of Mammary Tumors in Dogs

TREATMENT: Treatment for mammary tumors in dogs is surgical removal. Surgery involves removal of either the mass alone or the affected mammary gland. Benign tumors are cured by complete surgical resection, although the development of new mammary tumors in dogs (both benign and malignant) is still possible.

In advanced breast cancers where metastasis has occurred surgery will not be curative but may still be an option to reduce the burden of the tumor and improve the dog's quality of life. Metastasis is when the cancer has spread from where it originated to other organs or parts of the body.

PREVENTION: There are few cancers that are as easily prevented as mammary cancer in dogs. The answer: Simply spay your female dog before her first heat. It is one of the best things pet owners can do to improve their dog's health and increase their lifespan.

Other factors that may reduce the incidence of mammary tumors in dogs and other cancer(s) in dogs include:

  • Feeding your dog a well-balanced diet. Your dogs diet is one of the things that you do have control over. Provide a natural diet with as many fresh, raw, whole foods as possible. and keeping your dog's weight down, thus avoiding obesity.
  • Give your pet antioxidants, Omega-3 (EPA an DHA), and other supplements to support immune function, decrease inflammation, and promote cellular health.
  • Offer only purified, filtered water as tap water contains chemicals, and other toxins.
  • Eliminate chemical toxins used in and around your home; choose non-toxic, green cleaning products and reduce your pet’s exposure to fertilizers & pesticides.
  • Do not smoke around pets. If you must smoke, go outside!
  • Do not over-vaccinate, and never vaccinate a sick animal.
  • Avoid chemical flea & tick products and use natural insect control products instead.
  • Reduce emotional stress for your pet and yourself with flower essences, massage, homeopathy, and other energy therapies.
  • Exercise and play with dog every day to help relieve stress and avoid obesity.

If you do find a growth or lump in the mammary tissue of your dog (male or female dog) inform your veterinarian immediately.

Further Reading: Dogs and Cancer

How to Perform a Breast Exam on Your Dog

The steps are simple to do and so important as early detection is key.

  1. While your dog is standing, feel under the belly and all the way up under the armpit areas. Massage small areas at a time feeling for any unusual lumps or swelling.
  2. Have your dog roll over onto her back, with belly facing up towards you. Continue to massage around each nipple. Roll the breast tissue between your fingers, gently. Massage the glands using light pressure only. Again you are feeling for any lumps or swelling.
  3. While your dog is lying down on her back be sure to inspect each nipple for any inflammation.

If you feel any tiny lump, don't wait to see if it gets better. Take your dog in to see the vet right for a proper diagnosis.

Natural Cancer Care for Dogs

Pet BSST Herbal Formula is designed to help strengthen the innate defense mechanisms of the body to support the immune system’s ability to fight pathogenic and system-degenerative ailments and to destroy abnormal cells.

Guide to Natural Pet Care Cancer Comprehensively covers gentle, natural treatments for cancer in both dogs and cats. Delves into the latest scientific research and veterinary clinical trials, as well as actual cases in which pets have been cured by holistic medicine.

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