Signs of Breast Cancer in Dogs: What You Need to Know

Breast cancer is a common and serious disease that affects many female dogs, especially those that are not spayed or spayed late in life. Breast cancer in dogs is also known as mammary cancer or mammary tumors, and it can be benign (non-cancerous) or malignant (cancerous).

In this article, we will focus on the signs of malignant breast cancer in dogs, which is the most dangerous and aggressive form of the disease.

Malignant breast cancer in dogs can spread to other organs and tissues, such as the lungs, lymph nodes, bones, and blood vessels, and cause life-threatening complications. Therefore, it is crucial to detect and treat breast cancer in dogs as early as possible, before it becomes too advanced and difficult to manage.

In this article, we will cover the following topics:

What are the causes and risk factors of breast cancer in dogs?
What are the symptoms and signs of breast cancer in dogs?
How is breast cancer in dogs diagnosed and treated?
How can you prevent breast cancer in dogs?
What is the prognosis and survival rate of breast cancer in dogs?

What are the causes and risk factors of breast cancer in dogs?

The exact causes of breast cancer in dogs are not fully understood, but there are several factors that can increase the risk of developing the disease. These include:

Sex: Breast cancer in dogs is more common in females than males, as females have more mammary tissue and hormones that can stimulate tumor growth.
Hormones: Exposure to progesterone and estrogen, the female reproductive hormones, can increase the risk of breast cancer in dogs. These hormones can be produced by the ovaries, or by external sources, such as hormone injections or pills. Progesterone and estrogen can stimulate the growth of abnormal cells in the mammary glands, which can eventually become cancerous.
Spaying: Spaying is the surgical removal of the ovaries and uterus in female dogs, which prevents them from producing hormones and having heat cycles. Spaying can significantly reduce the risk of breast cancer in dogs, especially if done before the first heat cycle. According to some studies, dogs spayed before their first heat cycle have only a 0.5% risk of developing breast cancer, compared to 8% and 26% for dogs spayed after their first or second heat cycle, respectively.
Age: The risk of breast cancer in dogs increases with age, as older dogs have more exposure to hormones and more chances of developing abnormal cells. The average age of diagnosis for breast cancer in dogs is 10 years, and the risk is highest between 7 and 13 years of age
Breed: Some breeds of dogs are more prone to breast cancer than others, due to genetic factors. These include Chihuahuas, Poodles, Dachshunds, Yorkshire Terriers, Cocker Spaniels, Brittany Spaniels, English Setters, Boxer Dogs, and Doberman Pinchers.
Other factors: Other factors that may contribute to breast cancer in dogs are obesity, inflammation, infection, trauma, or environmental toxins.

What are the symptoms and signs of breast cancer in dogs?

The most common sign of breast cancer in dogs is a lump or mass in the mammary glands, which are located on the chest and abdomen of the dog.

The mammary glands are arranged in two chains, one on each side of the body, and each chain has four or five glands. The lumps can vary in size, shape, texture, and number, and they can be found near or within the nipples, or along the mammary chain.

However, not all lumps are cancerous, and some may be benign or caused by other conditions, such as mammary gland hyperplasia, which is a hormonal enlargement of the breast tissue that usually resolves after the heat cycle. Therefore, it is important to have any lump checked by a veterinarian, who can perform tests to confirm or rule out breast cancer in dogs.

Other signs and symptoms of breast cancer in dogs may include:

Discharge from the nipples, which can be bloody, milky, or clear
Inflammation and redness of the skin over the lump
Ulceration or open sores on the lump, which can bleed or become infected
Pain or discomfort in the affected area, especially if the lump is large or pressing on other structures
Loss of appetite and weight loss, due to reduced interest in food or difficulty eating
Weakness and lethargy, due to anemia or low energy levels
Coughing or difficulty breathing, if the cancer has spread to the lungs
Limping or stiffness, if the cancer has spread to the bones

If you notice any of these signs or symptoms in your dog, you should take them to the veterinarian as soon as possible, as they may indicate a serious health problem.

How is breast cancer in dogs diagnosed and treated?

The diagnosis of breast cancer in dogs is based on a combination of physical examination, medical history, and diagnostic tests.

1.physical examination

The veterinarian will examine your dog’s mammary glands and look for any lumps, discharge, inflammation, or ulceration.

2.Medical History

The vet will also ask you about your dog’s spaying status, age, breed, and any other relevant information.

3.Diagnostic test

The diagnostic tests that may be performed to confirm or rule out breast cancer in dogs are:

Fine needle aspiration: This is a minimally invasive procedure that involves inserting a thin needle into the lump and extracting some cells for microscopic examination. This can help determine if the lump is benign or malignant, and what type of cancer it is.
Biopsy: This is a more invasive procedure that involves surgically removing a small piece of tissue from the lump and sending it to a laboratory for histopathological analysis. This can provide more detailed information about the type, grade, and stage of the cancer, and guide the treatment plan.
X-rays: These are imaging tests that can show if the cancer has spread to the lungs, bones, or other organs. They can also help assess the size and location of the tumor.
Ultrasound: This is another imaging test that can show the internal structure of the tumor and the surrounding tissues. It can also help detect any enlarged lymph nodes or fluid accumulation in the chest or abdomen.
Blood tests: These are laboratory tests that can measure the levels of blood cells, electrolytes, enzymes, and hormones in your dog’s blood. They can help evaluate your dog’s overall health and organ function, and detect any signs of infection, inflammation, or anemia.

The treatment of breast cancer in dogs depends on several factors, such as the type, grade, and stage of the cancer, the size and location of the tumor, the presence or absence of metastasis, and the overall health and age of the dog. The main treatment options are:

1.surgical treatment

Surgery: This is the most common and effective treatment for breast cancer in dogs, and it involves removing the tumor and the surrounding mammary tissue, as well as any affected lymph nodes.

The extent of the surgery depends on the size and number of the tumors, and it can range from a simple lumpectomy (removal of the lump) to a radical mastectomy (removal of the entire mammary chain).

Surgery can cure most cases of breast cancer in dogs, especially if done early and before the cancer has spread.

2.chemotherapy

Chemotherapy: This is the use of drugs that kill or stop the growth of cancer cells. it can be given orally, intravenously, or intramuscularly, and it can be used alone or in combination with surgery.

Chemotherapy can help shrink the tumor, prevent or delay the recurrence, and improve the survival rate of dogs with breast cancer.

Side effects of chemotherapy

However, chemotherapy can also cause side effects, such as nausea, vomiting, diarrhea, hair loss, and low blood cell counts.

3.Radiation therapy:

Radiation therapy: This is the use of high-energy rays that damage the DNA of cancer cells and prevent them from dividing.

Radiation therapy can be delivered externally or internally, and it can be used alone or in combination with surgery or chemotherapy. Radiation therapy can help reduce the size of the tumor, relieve pain, and improve the quality of life of dogs with breast cancer.

Side effects of radiation therapy

However, radiation therapy can also cause side effects, such as skin irritation, hair loss, and inflammation of the mouth or esophagus.

4.Hormone therapy:

Hormone therapy: This is the use of drugs that block or reduce the production or action of hormones that stimulate the growth of breast cancer in dogs. Hormone therapy can be given orally or by injection, and it can be used alone or in combination with other treatments. Hormone therapy can help slow down the progression of the disease, reduce the risk of recurrence, and prolong the survival of dogs with breast cancer

Side effects of hormonal treatment

However, hormone therapy can also cause side effects, such as weight gain, increased thirst and urination, and behavioral changes.

The choice of treatment for breast cancer in dogs depends on the individual case and the veterinarian’s recommendation. The goal of treatment is to remove or destroy the cancer cells, prevent or delay the spread of the disease, and improve the quality of life and comfort of the dog.

How can you prevent breast cancer in dogs?

The best way to prevent breast cancer in dogs is to spay them before their first heat cycle, which can reduce the risk of the disease by 99.5%. Spaying can also prevent other reproductive problems, such as pyometra (infection of the uterus), ovarian cysts, and uterine tumors.

If your dog is not spayed, you should monitor her mammary glands regularly, especially during and after her heat cycles, and look for any changes or abnormalities. You should also avoid giving her any hormonal supplements or medications, unless prescribed by your veterinarian.

Additionally, you should maintain your dog’s optimal weight, as obesity can increase the risk of breast cancer in dogs. You can do this by providing a balanced and nutritious diet, and ensuring regular exercise and physical activity for your dog.

Finally, you should take your dog to the veterinarian for routine check-ups and screenings, especially if she is older or belongs to a high-risk breed. Early detection and treatment can make a big difference in the outcome and prognosis of breast cancer in dogs.

What is the prognosis and survival rate of breast cancer in dogs?

The prognosis and survival rate of breast cancer in dogs depend on several factors, such as the type, grade, and stage of the cancer, the size and location of the tumor, the presence or absence of metastasis, and the response to treatment.

In general, the prognosis and survival rate of breast cancer in dogs are better if the cancer is detected and treated early, before it has spread to other organs or tissues.

According to some studies, the median survival time for dogs with breast cancer that undergo surgery is 24 months, and the 2-year survival rate is 50%. However, these numbers can vary widely depending on the individual case and the treatment options available.

Some factors that can improve the prognosis and survival rate of breast cancer in dogs are:

Spaying: Spaying can reduce the risk of recurrence and improve the survival rate of dogs with breast cancer, especially if done at the same time as the tumor removal.
Chemotherapy: Chemotherapy can increase the survival rate of dogs with breast cancer, especially if the cancer is high-grade, large, or has spread to the lymph nodes or other organs.
Radiation therapy: Radiation therapy can improve the quality of life and prolong the survival of dogs with breast cancer, especially if the tumor is inoperable, recurrent, or causing pain.
Hormone therapy: Hormone therapy can slow down the progression of the disease and extend the survival of dogs with breast cancer, especially if the tumor is hormone-dependent.

Some factors that can worsen the prognosis and survival rate of breast cancer in dogs are:

Delay in diagnosis and treatment: Delay in diagnosis and treatment can allow the cancer to grow larger and spread further, making it more difficult and less effective to treat.
Metastasis: Metastasis is the spread of cancer cells to other organs or tissues, such as the lungs, bones, liver, or brain. Metastasis can cause serious complications and reduce the survival rate of dogs with breast cancer.
Inflammation and infection: Inflammation and infection can compromise the immune system and the healing process of dogs with breast cancer, and increase the risk of complications and recurrence.
Poor health and age: Poor health and age can affect the ability of dogs with breast cancer to tolerate and respond to treatment, and increase the risk of side effects and complications.

Breast cancer in dogs is a complex and challenging disease that requires prompt and appropriate veterinary care. However, with early detection and treatment, many dogs with breast cancer can live long and happy lives.

Breast Cancer in Dogs