Benign or malignant tumors are common in unneutered female dogs. In fact, mammary tumor in dogs is the most common type of tumor in unneutered female dogs. The job of the mammary glands in female dogs is to produce milk for newborn puppies. The part of the glands, which are in two rows from the chest to the lower abdomen, protruding out of the body is expressed as the nipple. Tumors occurring here can cause serious problems for dogs. Although breast cancer is extremely common among female dogs, it is rarely seen in male dogs. Sterilization greatly reduces the risk of breast cancer. In fact, it is more effective when female dogs are neutered before they go into heat. In this article, we will discuss what you need to know about breast cancer in dogs.
Types of Mammary Tumors in Dogs
There are two types of mammary tumors in dogs: benign and malignant. It can be said that the tumors are benign in half of the dogs with mammary tumors. These are divided into adenomas or mixed tumors. Half of the dogs with mammary tumors are malignant. These include some types such as carcinoma, carcinoma in situ, and cystic papillary. A wide variety of malignant tumors can be encountered, but these are the most common ones.
Causes of Breast Cancer in Dogs
The causes of mammary mass formation in dogs are still not fully known. It is thought that hormones and genetic predispositions have an effect on tumor formation. In particular, genes in some breeds cause dogs to be more prone to breast cancer. The risk of developing mammary tumors is higher in Toy or Mini Poodle, English Springer Spaniel, English Cocker Spaniel, English Setter, Pointer, German Shepherd Dog, Maltese and Yorkshire Terrier types compared to other breeds. Female reproductive hormone increases the risk of breast cancer in dogs. According to studies, the risk of breast cancer in dogs that have never been in heat is around 0.5%. Breast cancer occurs in dogs between the ages of 1 and 15. However, tumor formation occurs very rarely in dogs under 5 years of age. The mean age of breast cancer can be expressed as 10.5.
Breast Cancer Symptoms in Dogs
Tumor signs in the mammary glands are seen quite clearly in dogs. Single or multiple masses in the mammary glands are the most important symptom. More than one tumor formation occurs in almost half of the diseases. Superficial tissue loss due to inflammation and discharge on the skin surface on the breast tissue is another common symptom. The mass in the breast tissue can sometimes move freely, which usually indicates that the tumor is benign. Masses that are attached to the skin, fixed or barely moving, are usually malignant. Swelling in the lymph nodes is another symptom of breast cancer in dogs. In cases where the cancer has spread to the lungs, in addition to these symptoms, difficulty in breathing is also seen.
How Are Dogs Diagnosed with Breast Cancer?
Other ailments may also cause symptoms similar to those of a mammary mass in dogs. The veterinarian usually rules out these possibilities before concluding cancer. At this point, it is extremely important to give the veterinarian complete information about the dog’s disease history, reproductive history and symptoms. Tests such as complete blood count and urinalysis can be done to diagnose breast cancer. In addition, X-rays of the chest and abdomen also show metastasis, if any. Biopsy is usually performed to understand whether the mass is benign or malignant. Similarly, pieces can be taken from the lymph nodes.
Breast Cancer Treatment in Dogs
There are some treatment options for mammary tumors in dogs. At this point, it is necessary to choose the most effective treatment according to the type, location and number of the tumor. Usually, the tumor needs to be removed by surgical intervention. It can be used together with some other treatment methods, and the healing process can be comfortably passed. Some tumors are extremely aggressive and penetrate deep into nearby tissues. In such cases, only a part of the tumor can be removed. Afterwards, the deep tumor is treated with chemotherapy and radiation therapy. In surgeries where the tumor is removed from the body, neutering the dog increases its chances of living longer. During the treatment process, the dog’s condition is followed up with regular physical examinations and x-rays.
Can Breast Cancer In Dogs Be Prevented?
The most effective measure that can be taken to reduce the likelihood of breast cancer in dogs is neutering. The probability of mammary cancer is 0.5% in dogs spayed without ever entering heat. When spayed after the first heat, this rate rises to 8%. The chance of developing breast cancer is 26% if neutered after the second heat. After the dog is 2.5 years old, neutering does not have any preventive effects. For more detailed information about neutering in dogs, “What are the Benefits and Harms of Neutering?” You can read our blog post.
The effects of breast cancer on the lifespan of the dog vary according to the condition of the cancer. In general, dogs with small tumors have a longer life expectancy than dogs with large tumors. In cases where cancer metastasizes to the lymph nodes, life expectancy is lower. In cases where the cancer has spread to more distant places, such as the lungs, the expectation is lowest. In addition, the treatment process is extremely difficult in such cases. At this point, the preferred treatment method is also very important. Again, although it varies according to the condition of the cancer, the average life expectancy in dogs who only underwent surgery is 6 months. This period may take up to 24 months in dogs who have undergone surgery and continue to receive additional treatment such as chemotherapy afterwards.