LYMPHOMA
DESCRIPTION
Lymphoma, also called lymphosarcoma, is a highly malignant tumour of the lymph system. It is the most common form of cancer in both humans and small animals.
The lymph system is a network of lymphatic vessels and lymph nodes that exist in throughout the body. They help clean the body of unwanted substances and give protection against foreign substances. The lymph nodes serve as immune system centers where these foreign substances may be presented to the cells (lymphocytes) of the immune system. There are many different types of immune-related cells; some produce anti-bodies, some circulate and destroy the foreign materials they encounter, some regulate the activity of other cells.
When lymphocytes become cancerous within a lymph node, the node swells and hardens. Malignant lymphocytes readily travel through the lymph vessels to nearby lymph nodes. Soon all the nodes are enlarged. Ultimately, the bone marrow (where most blood cells are formed) is affected, the immune system is destroyed, and severe anemia and weakness claim the victim's life.
DIAGNOSIS
Lymphoma is often diagnosed when the owner finds enlarged lymph nodes in the dog’s neck, point of the shoulder, groin and behind the knees. The veterinarian will usually take a biopsy of one or more of these lymph nodes and will often ultrasound the abdomen or take a bone marrow biopsy to confirm the diagnosis. Blood work will sometimes show an elevated Calcium level.
Lymphoma is classified by stage:
Stage I: - only one lymph node involved
Stage II: - several lymph nodes in the same general area involved
Stage III: - all peripheral lymph nodes involved
Stage IV: - all peripheral lymph nodes plus the spleen, liver, and/or anterior mediastinum in the chest involved
Stage V: - everything in stage IV plus bone marrow involvement
Prognosis:
Without treatment, most pets live 6-8 weeks after the diagnosis is made.
With treatment the average survival time is 1 year. With treatment the survival time may be as little as 4 months or as long as 2 years.
Unfortunately for lymphoma, there is no cure.
TREATMENT
There are variations of chemotherapy protocols used to treat lymphoma. Seventy-five percent of all patients will reach remission with treatment. Once the pet comes out of remission the treatment program can be run again, but the second remission will only last ½ of the time that the first remission lasted.
More aggressive programs such as the protocols that use a combination of weekly treatments of L-Asparginase, Doxorubicin, Vincristine, Cyclophosphamide and Prednisone have the longest survival times. These programs give the best results. Dogs are frequently put on drugs to decrease nausea and vomiting for the first few days after these drugs have been given but most dogs show little discomfort and only loss of some whiskers.
Shorter programs that only use one or several drugs are sometimes used, but the survival time is significantly shorter.
In some cases half body radiation is used to slow the disease down. This is where the patient receives radiation over ½ of its body at a time, in an attempt to kill off the cancer cells.
Other cancer types.
