Breast Cancer in Dogs

Breast cancer in dogs, also known as canine mammary cancer, is a common and serious condition that predominantly affects unspayed female dogs. Approximately 50% of all mammary tumors in dogs are malignant, meaning they have the potential to spread (metastasize) to other parts of the body. Early detection and treatment are crucial for improving the dog's prognosis. Why not follow this article to catch what you want to know about canine breast cancer?

   

Can Dogs Get Breast Cancer?

Yes, dogs can develop breast cancer. It is more common in female dogs, especially those that are not spayed or were spayed later in life. Unspayed females are at a significantly higher risk because the development of breast cancer in dogs is strongly linked to hormonal exposure. Male dogs, while much less frequently affected, can also develop mammary cancer, though it is exceedingly rare.

Risk Factors for Mammary Cancer in Dogs

The primary risk factors for mammary cancer in dogs include:

• Not being spayed or late spaying:
  Dogs spayed before their first heat cycle have a greatly reduced risk of developing mammary tumors.
• Age:
  Mammary cancer is more common in middle-aged to older dogs, typically those over six years of age.
• Hormonal exposure:
  Estrogen and progesterone exposure, whether naturally occurring or from hormone-based medications, increases the risk.
• Breed predisposition:
  Certain breeds, such as Poodles, Dachshunds, Spaniels, and Terriers, are more prone to developing mammary tumors.

Canine Breast Cancer: What Is Adenocarcinoma?

Adenocarcinoma is a type of malignant tumor that arises from glandular tissue, including the mammary glands. In dogs, mammary adenocarcinoma is one of the most common forms of breast cancer. These tumors are aggressive, can invade nearby tissues, and often metastasize to the lymph nodes, lungs, and other organs. Adenocarcinomas vary in size and consistency, and their malignancy is determined by biopsy and histopathology (examining the tissue under a microscope).

Symptoms of Mammary Cancer in Dogs

Symptoms of breast cancer in dogs include:

Lumps or masses in the mammary gland area:
These are often firm, irregular in shape, and attached to underlying tissues. They can appear singly or in clusters.

Swelling or discharge from the mammary glands:
In some cases, the affected gland may become swollen or develop ulcers that ooze fluid or blood.

Changes in behavior:
The dog may exhibit signs of discomfort, lethargy, or reduced appetite as the tumor grows.

Difficulty breathing:
If the cancer spreads to the lungs, respiratory issues may arise.

Dog Mammary Cancer Stages

Like in human oncology, canine mammary cancer is categorized into stages based on the size of the tumor and the extent of its spread. The staging helps determine the best course of treatment and provides a prognosis.

• Stage 1: Tumor size is less than 3 cm in diameter, and there is no evidence of metastasis.
• Stage 2: Tumor size is between 3 and 5 cm, with no metastasis.
• Stage 3: Tumor size is greater than 5 cm, but it has not spread to other tissues.
• Stage 4: The tumor has metastasized to nearby lymph nodes or other local tissues.
• Stage 5: The cancer has spread to distant organs, such as the lungs or liver.

How Treatable Is Breast Cancer in Dogs?

The treatability of breast cancer in dogs depends on several factors, including the stage of the cancer at the time of diagnosis, the type of tumor, and the overall health of the dog. When detected early and treated aggressively, many dogs with mammary cancer can have a good prognosis.

Treatment Options for Breast Cancer in Dogs

Treatment for canine breast cancer often involves a combination of surgery, chemotherapy, and in some cases, radiation therapy. The goal is to remove the tumor, prevent recurrence, and manage any metastasis.

Surgical removal (mastectomy):
The primary treatment for mammary cancer in dogs is surgery to remove the affected mammary gland(s). If the tumor is localized, a simple mastectomy (removal of the tumor and surrounding tissue) is performed. In more advanced cases, a full mastectomy (removal of all mammary glands on one or both sides) may be necessary.

Chemotherapy:
Chemotherapy is used when the cancer is aggressive or has metastasized. It can help shrink tumors, slow the spread of cancer, and prolong the dog’s life. Drugs like doxorubicin and carboplatin are commonly used.

Radiation therapy:
Radiation may be used post-surgery to destroy any remaining cancer cells and reduce the chance of recurrence. However, it is not a standard treatment for all cases and is used on a case-by-case basis.

Hyperthermia treatment:
Hyperthermia involves applying heat to cancerous tissues to destroy or weaken them. It can be used alongside surgery, chemotherapy, or radiation therapy to enhance treatment outcomes. Hyperthermia works by making cancer cells more sensitive to radiation and chemotherapy, or it may be used directly to destroy cancer cells. While it is not as common as other treatments, it shows promise as a complementary therapy for certain cancers, including canine breast cancer.

How to Treat Breast Cancer with Hyperthermia in Dogs

Hyperthermia treatment for breast cancer in dogs involves heating the tumor tissue to temperatures that kill cancer cells or enhance the effectiveness of other therapies. The heat is delivered through external sources, such as microwave or radiofrequency devices, or through internal probes inserted into the tumor.

The mechanism behind hyperthermia's effectiveness is that cancer cells are more sensitive to heat than normal cells. When exposed to high temperatures (typically 40-45°C or 104-113°F), cancer cells become more vulnerable to radiation and chemotherapy, increasing the efficacy of these treatments.

• Localized hyperthermia:
  In this approach, only the tumor area is heated, minimizing damage to surrounding healthy tissues.
• Whole-body hyperthermia:
  This method is less common but involves heating the entire body to treat metastatic cancer.

Hyperthermia is generally used in conjunction with other treatments and is considered a promising addition to cancer therapy. Research into its full potential for treating breast cancer in dogs is ongoing, and veterinarians may recommend it depending on the individual case.

What Age Do Dogs Get Breast Cancer?

Dogs are most likely to develop mammary cancer between the ages of 6 and 10 years, though it can occur earlier or later in life. Spaying a dog before her first heat cycle drastically reduces the risk of developing breast cancer. Dogs spayed after multiple heat cycles are at a significantly higher risk.
Also Read: Can A Dog Be Spayed While in Heat

How Long Can a Female Dog Live with Breast Cancer?

The prognosis for a dog with breast cancer depends on several factors, including the stage of cancer at diagnosis, the type of tumor, and whether it has metastasized. For dogs diagnosed with early-stage, localized mammary cancer, the prognosis is relatively good, with many dogs living for several years following successful treatment.

For dogs with advanced or metastatic breast cancer, the prognosis is poorer. With appropriate treatment, some dogs may live for several months to a year, but the disease often becomes fatal in advanced stages.

When Should I Euthanize My Dog with Mammary Cancer?

Deciding when to euthanize a dog with mammary cancer is one of the most difficult decisions a pet owner can face. Factors to consider include the dog's quality of life, response to treatment, and the progression of the disease. Signs that it may be time to consider euthanasia include:

• Severe, unmanageable pain
• Difficulty breathing
• Loss of appetite and significant weight loss
• Inability to walk or stand
• Multiple metastases or the spread of cancer to major organs

It is essential to work closely with your veterinarian to assess your dog's condition and determine the most compassionate course of action.

How Fatal Is Mammary Cancer in Dogs?

The fatality rate of mammary cancer in dogs depends on the stage at which the cancer is diagnosed and treated. Early detection and treatment dramatically improve the survival rate. Dogs with benign tumors or those diagnosed with localized, non-metastatic mammary cancer have a much better prognosis compared to those with malignant or advanced-stage cancer. If left untreated, mammary cancer can be fatal as it progresses to other organs, such as the lungs or liver.

Conclusion

Breast cancer in dogs is a serious and potentially life-threatening condition, but with early detection, prompt treatment, and innovative therapies like hyperthermia, many dogs can go on to live healthy lives. If you notice any abnormal lumps or changes in your dog's mammary glands, it is crucial to consult your veterinarian immediately for an accurate diagnosis and treatment plan. Whether through surgery, chemotherapy, or alternative treatments like hyperthermia, timely intervention can significantly improve your dog’s prognosis and quality of life. 

FAQ Section

Q: Can dogs get breast cancer?  

A: Yes, dogs can develop breast cancer, also known as canine mammary cancer. It is more common in female dogs, especially those that are not spayed or spayed later in life.

Q: How treatable is breast cancer in dogs?  

A: The treatability of breast cancer in dogs depends on the stage of cancer at diagnosis. Early-stage breast cancer is highly treatable, especially with surgery, and some dogs may live cancer-free for years.

Q: What age do dogs get breast cancer?  

A: Dogs are most likely to develop mammary cancer between the ages of 6 and 10, particularly if they have not been spayed.

Q: How long can a female dog live with breast cancer? 

A: Life expectancy depends on the stage and type of tumor. Early-stage breast cancer has a good prognosis with treatment, but late-stage or metastatic cancer can significantly shorten a dog's life.

Q: When should I euthanize my dog with mammary cancer?

A: Euthanasia should be considered when the dog’s quality of life has deteriorated, such as when they experience severe pain, have difficulty breathing, or are unable to eat or walk.

Q: How fatal is mammary cancer in dogs?

A: Mammary cancer can be fatal, especially if it is malignant or diagnosed at an advanced stage. However, early detection and treatment can significantly improve survival rates.