What are canine mammary tumours?

Canine mammary tumours are a type of cancer that affects the mammary glands in female dogs. The mammary glands are located in the chest and abdominal area and are responsible for producing milk for nursing puppies. Canine mammary carcinomas, that represent a wide spectrum of diseases with different behaviour, is one of the most common forms of cancer in female dogs, particularly those that have not been spayed. Sarcomas can also be seen but are more rare.

Risk Factors:

Unspayed female dogs are at a higher risk of developing mammary carcinomas. Other risk factors include older age, breed (some breeds are more prone to developing this type of cancer), and a history of mammary tumours. Obesity and exposure to environmental hormones have also been associated with an increased risk of mammary carcinomas in dogs.

Symptoms

Symptoms of canine mammary carcinoma can include:

• Lumps or masses in the mammary glands
• Swelling or enlargement of the mammary glands
• Changes in the skin over the mammary glands (such as ulceration or crusting)
• Occasionally loss of appetite, weight loss or lethargy

Diagnosis

Diagnosis of canine mammary tumours is typically made through a biopsy of the mass. In many cases, additional tests such as blood tests, X-rays, ultrasound, or CT scans can be necessary to determine the extent of the cancer as the malignant ones can spread to the local lymph glands and lungs. Needle samples can help but cannot always differentiate between malignant and benign tumours.

Treatment

Treatment options for canine mammary carcinomas include surgery and chemotherapy (and rarely radiation therapy only in inflammatory carcinomas). The type of treatment (extent of surgery +/- chemotherapy) that is best for a particular dog will depend on the stage, type, subtype and location of the cancer, as well as the overall health of the dog. In some cases, a combination of treatments can be recommended.

Prognosis

It is important to note that early detection and treatment is crucial in improving the prognosis for dogs with canine mammary carcinomas. Female dogs that have not been spayed are at a higher risk of developing mammary carcinoma, and spaying a dog before its first heat cycle can greatly reduce its risk of developing the disease. Regular check-ups and prompt examination of any lumps or masses that are found can also help increase the chances of early detection and successful treatment.

Prognosis in canine mammary carcinomas is dependent on the stage, grade, type, subtype and location of the cancer, as well as the overall health of the dog. Your Oncologist will advise on the prognosis after the initial diagnostic tests.

What are inflammatory carcinomas?

Inflammatory carcinomas are a type of mammary carcinoma in dogs that are characterized by the presence of inflammation in the affected mammary gland due to blockage of lymphatic vessels.

This type of cancer tends to be more aggressive than other types of mammary carcinomas and often might spread quickly to other parts of the body.

Signs and Symptoms:

The signs and symptoms of inflammatory carcinomas in dogs can include the following:

• Swelling and redness of the mammary gland
• Pain in the affected mammary gland
• Discharge from the mammary gland
• Altered nipples (such as redness, swelling, or discharge)
• Loss of appetite
• Depression
• Weight loss

Diagnosis

Diagnosis of inflammatory carcinomas in dogs typically involves a physical examination, biopsy of the affected mammary gland, and other diagnostic tests (such as blood tests, x-rays, and ultrasound or CT scan).

Treatment

The treatment options for inflammatory mammary carcinomas are slightly different than the typical canine mammary carcinomas.

Common treatment options include radiation therapy and chemotherapy (either injectable or oral). Surgery is not the preferred treatment approach as it doesn’t improve survival and might only be considered for pain palliation.

Prognosis

Prognosis is usually guarded but multimodal treatment can help improve a patient quality of life and lifespan.

If you have any further questions, please do not hesitate to contact the hospital.