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Mammary Tumors In Dogs

Mammary Tumors In Dogs

Canine mammary gland tumors (CMGTs) are common in female dogs that were either spayed after the first heat cycle or are not spayed at all. Mammarian carcinomas are malignant growths in the surface cells of mammary tissues of one or several of the teats.

Canine Mammary gland tumors are relatively heterogeneous in terms of biological behavior and morphology. Of all neoplasms in female dogs, the occurrence of mammary tumors is estimated at 50%, of which approximately 40% are malignant and 60% are benign. Mammary glands closest to the groin (fourth and fifth mammary glands) are most commonly affected. The mammary tumors usually affect older females with mean onset age is 8 - 11 years.

The neoplasms could appear as a soft or hard lump in the mammary gland area. At the start, it will be covered with hair and skin. Advanced tumors could rupture and resembles an abscess. As this is often occurring cancer in canines, it is essential for every owner to check out the mammary area for lumps regularly.

There are several different types of CMGTs, including primary cancers such as carcinomas being the most common. Carcinomas occur in skin (epithelial) cells of mammary glands, other cells found in the mammary chain, or tubules of the mammary glands. There are other metastatic cancers that can affect mammary glands (such as osteosarcomas).

Symptoms Of Mammary Tumors

  • Mass or lumps in the mammary glands.
  • Colored, red or purple, soft or hard, or sometimes ulcerated mass.
  • Multiple bumps
  • Painful or swollen breasts
  • Lameness
  • Yellow discharge or pus from the nipple.
  • Breathing difficulties

Treatment Options For Mammary Tumors

  • Intracavitary chemotherapy of cisplatin - A high dose of chemotherapy is injected into the tumor, but the rest of the body receives only a very low dose and it is used to control malignant effusions.
  • Oophorectomy - Surgical removal of the ovary/ovaries (an alternative to ovariohysterectomy).
  • Ovariohysterectomy - ovaries and uterus are removed.
  • Mammary gland removal.

Home Remedies For Mammary Tumors

As with any disease, the prognosis is dependent on the extent of the disease, its location, and the treatment chosen.

More importantly, follow the instructions given to you by your veterinarian. Follow up with thoracic and abdominal radiographs once in 2 months if any metastasis is indicated or monitor for recurrence.

Discuss home treatments with your vet to ensure they won’t mess with other medications.

Prevention Of Mammary Tumors

The only way of prevention is by having your pet spayed (removal of ovaries) and this completely prevents the chance of this happening.

Spaying also prevents uterine infections, and accidental pregnancy and decreases the chances of mammary cancer by over 50%.

Affected Breeds Of Mammary Tumors

Spaniel Dog Breeds, Poodle, Toy Dachshund, Terrier Dog Breeds, Boston Terrier, Brittany Spaniel, Cocker Spaniel, Dachshund, English Springer Spaniel, English Setter, Fox Terrier, Toy Poodle, German Shepherd, German Shorthaired Pointer, German Wirehaired Pointer

Additional Facts For Mammary Tumors

  1. Risk Factors:
  • Mostly idiopathic/hereditary
  • Old age
  • Intact dogs / Spayed after a first heat cycle.
  • Overweight or obese
  1. Types:

Benign Tumors (60%): Simple adenomas; fibroadenomas (benign mixed tumors); benign mesenchymal tumors.

Malignant Tumors (40%): Anaplastic carcinomas, solid carcinomas, carcinosarcomas (malignant mixed tumors), papillary carcinomas, tubular Adenocarcinomas, etc.

They are classified based on the action.

Infiltrating Tumors: Infiltrating lobular carcinoma, simple or complex infiltrating canalicular carcinoma, spindle cell carcinoma, epithelioid carcinoma, etc.

Non-infiltrating Tumors: Lobular carcinoma and intracanalicular carcinoma.

  1. Stages:
  • Stage 0: Carcinoma in situ; malignant proliferation limited to mammary ducts.
  • Stage 1: Malignant spread extends outside the anatomical confines of the mammary ducts, intruding the nearby stroma. Invasive carcinoma lymph node and vascular identification.
  • Stage 2: Carcinoma metastases in the regional lymph nodes or with lymphatic or vascular invasion.
  • Stage 3: Apparent metastatic disease. The most advanced stage. Cancer has metastasized to distant organs.
  1. Morbidity:
  • Mammary tumor peak incidence in dogs is between 8 to 12 years.
  • CMGTs such as carcinomas are the most prevalent tumors of mammary ducts.
  • Carcinomas occur in skin (epithelial) cells of mammary glands, other cells found in the mammary chain, or tubules of the mammary ducts.
  1. Mortality:

The asymptomatic nature, no apparent symptoms during the growth of the tumor or delayed onset of symptoms, and lack of proper screening results in the high mortality rate of mammary cancer.

  1. Diagnosis:
  • Baseline tests - Complete blood count (CBC), Biochemical profile, and Urinalysis.
  • Abdominal radiographs (X-rays) and thoracic radiographs.
  • Abdominal ultrasound
  • Cytology (evaluation of cells) - To check the presence of abdominal or thoracic fluid.
  • Microscopic evaluation and Biopsy are necessary for a definitive diagnosis.
  1. Prognosis:

Stage I and II dogs can have a good prognosis. The five-year survival rate for stage I and II cancer is approximately 70%. After the removal of tumors, the survival rate is estimated at four to six years.

When all types of mammary cancer are taken together almost 3 in 4 dogs' survival rate is at least 1 year after diagnosis.

When To See A Vet

Contact your vetright away, if you notice any of the following:

  • Mass or lumps in the mammary glands.
  • Colored, red or purple, soft or hard, or sometimes ulcerated mass.
  • Multiple bumps

Food Suggestions For Mammary Tumors

  • Consider a diet with all essential nutrients and also provides plenty of antioxidants (combat free radicals).
  • Fresh, organic meats, either raw or cooked.
  • Chicken / Fish / Organ meat / Eggs.
  • Dark-green, leafy vegetables like spinach,
  • Cooked Spinach and Potatoes, Rice, Sweet potato, and Mashed banana.
  • Omega 3 fatty acid foods (Sardines, Mackerel, Herring, etc).


For dogs with mammary cancer, the long-term prognosis is generally poor, regardless of treatment. Dogs can have an improved quality of life for a period of time with proper treatment.

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