At Hallett Veterinary Hospital, we understand that your canine companion is not just a pet, but also a beloved, cherished family member. The mutual bond of love and loyalty between you can make a diagnosis of any form of cancer very difficult to hear. Our veterinarians and support staff are empathetic, compassionate and trained to focus on both the emotional and medical aspects of cancer.
We are here to guide you both through the diagnosis and treatment process. This includes choosing the best options for effectively, humanely and successfully dealing with canine cancer.
Common Types Of Cancer In Dogs
Unlike many other species of animals, dogs are susceptible to many of the same types of cancer as humans. Cancer is caused by the uncontrolled growth of cells in the body. These cells can originate in any of the body's tissues. If not found and arrested in time, cancer can expand and connect with the circulatory or lymph systems, and it also can spread and infect other tissues in the body. Canine cancer is the leading cause of death for dogs 10 years of age and older. However, half of all cancer in dogs is treatable if it is arrested in its early stages.
The most common types of cancer in dogs are:
- Hemangiosarcoma: This form of dog cancer is an incurable tumor of cells that line blood vessels, called endothelial cells. Although dogs of any age and breed are susceptible to Hemangiosarcoma, it occurs more commonly in middle-aged or elderly dogs. Also, certain breeds have a much higher incidence including Golden Retrievers and German Shepherds. For this reason, we may recommend additional screening of these breeds after age 5. This form of cancer develops slowly and is essentially painless, so clinical signs are usually not evident until the advanced stages when the tumors are resistant to most treatments. Less than 50% of treated dogs survive more than six months, and many die from severe internal bleeding before there is an opportunity to institute treatment.
- Mast Cell Tumors: These are immune cells that are responsible for allergies. Mast cells can be found in all tissues of the body but typically form tumors on the skin in close to 20 percent in the canine population. They range from relatively benign to extremely aggressive. Certain breeds of dog are at an increased risk for the development of this tumor, indicating that genetics might be a cause. Boxers are especially prone to this type of cancer.
- Lymphoma: This form of cancer can affect any dog of any breed at any age. Most of the time, it appears as swollen glands (lymph nodes) that can be seen or felt under the neck, in front of the shoulders, or behind the knee. Occasionally, lymphoma can affect lymph nodes that are not visible from outside the body, such as those inside the chest or in the abdomen. This can cause trouble breathing and digestive trouble. Generally, this form of dog cancer is considered treatable if arrested in its early stages. Standard Poodles, Golden Retrievers, and Australian Shepherds are a few of the breeds with a higher incidence of lymphoma.
- Osteosarcoma: This form of cancer is the most common type of primary bone cancer in dogs, accounting for up to 85% of tumors that originate in the skeletal system. Although it mostly affects older large or giant breed dogs, it can affect dogs of any size or age. Osteosarcoma occurs in many areas, but it most commonly affects the bones bordering the shoulder, wrist, and knee. Major symptoms include lameness in the affected leg or a swelling over the area that seems painful at the site.
- Brain Tumors: Epileptic-like seizures or other extreme behavioral changes are usually the only clinical signs of brain tumors. CAT scanning and MRI are used to determine the location, size, and severity. Although some oral chemotherapy and radiation therapy can control some inoperable tumors, surgical intervention may be recommended if the tumor is operable.
- Bladder Cancer: Some breeds are more at risk for this form of cancer than others. This is a slow developing cancer, and symptoms may not show for 3 to 6 months. Urinary obstruction and bleeding are common symptoms.
- Mammary Carcinoma: Non-spayed females are at high risk for developing malignant mammary tumors, but all females regardless of reproductive state remain at risk. Approximately 50% of these tumors are malignant, and complete surgical removal is recommended if the cancer has not metastasized.
- Malignant Histiocytosis: This cancer affects larger sport breeds most often. It occurs as localized lesions in the spleen, lymph nodes, lung, bone marrow, skin and subcutis, brain, and periarticular tissue of large appendicular (limb) joints. Histiocytic sarcomas can also occur as multiple lesions in single organs (especially spleen), and rapidly disseminate to involve multiple organs. Unfortunately, there is no reported effective therapy for this form of dog cancer.
- Squamous Cell Carcinomas (SCC): It is most often found in the mouth and the nail beds of the toes. Early detection and complete surgical removal is the most common treatment. Fewer than 20% of dogs develop metastatic disease. SCC of the tonsil and tongue are quite aggressive and fewer than 10% of dogs survive one year or longer despite treatment measures.
- Mouth and Nose Cancer: This is a very common form of cancer, more so in the mouth than the nose. Symptoms include a mass on the gums, bleeding, odor, or difficulty eating. Since many swellings are malignant, early, aggressive treatment is essential. Cancer may also develop inside the nose of dogs and cats. Bleeding from the nose, breathing difficulty, or facial swelling are symptoms that may indicate nose cancer.
- Melanoma: Melanomas arise from pigment-producing cells called melanocytes, which are responsible for coloring the skin. Melanomas can occur in areas of haired skin, where they usually form small, dark (brown to black) lumps, but can also appear as large, flat, wrinkled masses. Malignant melanoma, which develops in the mouth or in the distal limbs (usually the toenail beds), is an incurable disease. These tumors have very often spread to distant parts of the body by the time they are first noticed, making complete surgical removal impossible.
- Testicular: This form of dog cancer is common in unneutered dogs with retained testes. This form of dog cancer is largely preventable with neutering, and curable with surgery if arrested early in the disease process.
Symptoms And Signs Of Cancer
Some signs of cancer in dogs are easy to spot and others are not. Signs of cancer in dogs may vary greatly depending upon a number of factors. However, the following list identifies some of the most common signs of cancer in dogs:
- Lumps and bumps underneath a dog's skin
- Abnormal odors emanating from the mouth, ears or any other part of the body
- Abnormal discharge from the eyes, mouth, ears or rectum
- Abdominal swelling
- Non-healing wounds or sores
- Sudden and irreversible weight loss
- Change in appetite
- Coughing or difficulty breathing
- Lethargy or depression
- Changes in bathroom habits
- Evidence of pain
Should you witness any signs of cancer in your dog, we strongly recommend making a veterinary appointment immediately.
Diagnosing Canine Cancer
Only a veterinarian can accurately diagnose canine cancer. This is why it is extremely important to schedule periodic wellness exams for your canine companion. During these preventive exams, your veterinarian can check your dog for signs of canine cancer. Treating canine cancer before it advances is key to a successful recovery.
Treatment Options For Dogs With Cancer
Several factors influence cancer treatment decisions for dogs with cancer, including:
- Age of the dog
- The general health of the dog
- Tumor type
- The biological behavior of the tumor
- The Stage of the Cancer
The patient's overall health status plays a major role in therapy choices for dogs with cancer. This includes evaluating the patient for his or her ability to tolerate cancer treatment. Life expectancy should be taken into consideration as well; for a slow-growing tumor in an older dog, for example, treatment drawbacks may outweigh potential benefits.
Treatments for dogs with cancer are similar to human therapies, which can include:
- Radiation therapy
Our veterinarians and support staff will provide you and your canine companion with compassionate, comprehensive care and support services. Although cancer can be overwhelming, you don't have to go through it alone.