Canine and Feline Lymphoma

Lymphoma is a malignancy (cancer) arising from the lymphoid tissues involving the immune system as well as any organ. When the malignant cells are present in the patient’s bone marrow, causing blood disorders, it is referred to as leukemia. Some patients have multiple sites where malignant lymphocytes can be found. The patient can be staged (assessed for disease) as follows:

• Stage 1: Malignancy involves a single lymph node or single site.
• Stage 2: Involvement of a cluster of lymph nodes in a regional area (including a single tumor of the intestinal tract).
• Stage 3: Involvement of all peripheral lymph nodes.
• Stage 4: Involvement of liver and/or spleen; associated with shorter remissional/survival times.
• Stage 5: Involvement of the bone marrow and peripheral bloodstream; associated with shorter remissional/survival times. Substages: Lymphoma patients can be subdivided into:
• Substage A: Without systemic signs (ie. not ill).
  Substage B: With systemic signs (ie. physically ill).

Staging the cancer patient is vital in determining the best treatment and preparing prognostic information.

T-CELL VS. B-CELL LYMPHOMAS

You may see mention of lymphomas and leukemias as being either of a “B-cell” or “T-cell” origin. A patient’s biopsy tissue can be further tested by a technique called immunohistochemistry. This determines the type of cell of the immune system that the malignant clone arose from. The treatment options are the same for both types of lymphoma but over large numbers of patients, it has been shown that the T-cell lymphomas are generally more aggressive. Overall, patients with T-cell lymphomas achieve remission as often as B-cell lymphoma patients but their remission times can be significantly shorter (though not always).