WHAT YOU SHOULD KNOW ABOUT CANINE LYMPHO-SARCOMA

Stages of Lymphoma (According to the World Health Organization)

 Lymphosarcoma (Lymphoma) is the third most common cancer diagnosed in dogs. It is a cancer of lymphocytes (a type of blood cell) and lymphoid tissues. Lymphoid tissue is normally present in many places in the body including lymph nodes, spleen, liver, gastrointestinal tract and bone marrow.

The average dog with lymphosarcoma is between 6-9 years of age, although dogs of any age can be affected. Certain breeds may be more likely to develop this type of cancer. Males and females are equally at risk and in most cases the cause of lymphosarcoma is unknown.

 

 

 

Types of Lymphosarcoma

Lymphosarcoma can be divided into five different forms based upon the primary (predominant) site of the tumor.

1. The most common form involves one or more of the external lymph nodes. Symptoms range from the patient not feeling sick at all to tiredness, weight loss and weakness. The severity of the signs depends upon the extent of the tumor (s), and whether the cancer has caused changes in organ function. In many cases the only noticeable sign is an enlargement of the lymph nodes under the neck, behind the knees, or in front of the shoulders.

2. Dogs with Lympho-sarcoma of the gastrointestinal tract may have vomiting, diarrhea, weight loss, or a decreased appetite.

3.  The mediastinum is a term used for a special aggregation of lymphoid tissue in the chest. Dogs with Lympho-sarcoma of the mediastinum may have difficulty breathing or experience excessive thirst.

4. Lympho-sarcoma of the skin, known as cutaneous Lympho-sarcoma, can manifest as flaky, scaly, reddened skin that may or may not have lumps that can ulcerate. The foot pads, gums, lymph nodes, liver, spleen and bone marrow may be variably involved.

5. Cancer confined to the bone marrow is called leukemia. Anemia, infections and bleeding are common symptoms of leukemia. They are related to decreased numbers of normal cells, such as red blood cells which carry oxygen, white cells which fight infection, and platelets that help with clotting, which are made in the bone marrow.

Only 10-20 percent of dogs show symptoms of disease. The majority of dogs are brought to the veterinarian because of recently identified swellings or lumps. The treatment for Lymphoma in canines is chemotherapy. Lymphoma is considered a systemic disease, which makes surgery or radiation impractical or ineffective. There is a wide variety of chemotherapy protocols and drugs that are currently being used to treat canine lymphoma. The treatment usually consists of a combination of oral and inject able drugs given on a weekly basis. Some commonly used drugs include cyclophosphamide, vincristinem, doxorubicin, and prednisone. The exact treatment protocol will vary depending on the practitioner.

Some owners choose not to treat dogs that develop lymphoma. The life expectancy of these untreated dogs averages four to six weeks. Oral prednisone therapy may reduce the swellings and discomfort, but probably will not appreciably extend the patient's life span. It must also be noted that oral prednisone treatment prior to chemotherapy is not recommended and may actually reduce the effectiveness of the chemotherapy.

In dogs that undergo one of the recommended chemotherapy protocols, life expectancy can extend to a year and occasionally longer. If a dog tolerates chemotherapy (most dogs do) their quality of life can be quite good during the treatment period.