Lymphoma or lymphosarcoma is the most common type of cancer in cats, which is characterized by the abnormal proliferation of malignant lymphocytes. The incidence of this cancer has been observed to be higher in cats, as compared to dogs. It can affect any cat, irrespective of its breed and sex. Generally, lymphoma is classified into two categories - high-grade or lymphoblastic, and low-grade or lymphocytic.
Based on the location, the cancer is categorized as - multicentric, mediastinal, gastrointestinal, and extranodal lymphoma. The multicentric form of the cancer involves multiple lymph nodes, and it can affect multiple organs. Mediastinal lymphoma usually affects the lymph nodes located in the thorax and the thymus, while the extranodal form involves the central nervous system, skin, heart, kidneys, and the eyes. On the other hand, the gastrointestinal form of the cancer affects the digestive tract.
This condition can be associated with the infections caused by the feline leukemia virus. This virus is usually associated with the multicentric form of the disease. Earlier, the feline leukemia virus was recognized as the main factor responsible for the higher incidence of lymphoma in younger cats. However, with the growing use of vaccination, the incidence of this cancer in young cats has reduced significantly.
Earlier, the feline leukemia virus accounted for about 70% of the total cases of this cancer. But nowadays, only 20% of the total cases of feline lymphoma have been found to be associated with the feline leukemia virus. Another virus, known as the feline immunodeficiency virus, can also increase the risk of developing this cancer. Other factors that are supposed to play an important role in the development of this cancer are, a genetic predisposition, and the exposure to carcinogens like cigarette smoke.
Signs and Symptoms
This cancer can affect multiple organs, including the liver, spleen, central nervous system, kidneys, and the bone marrow. The symptoms of this condition can therefore, depend to a great extent on the particular organ or organs that are affected. Nevertheless, the most common signs and symptoms observed in this cancer are:
- Loss of appetite
- Progressive weight loss
- Diarrhea and vomiting
- Increased thirst and urination (when the kidneys are affected)
- Difficulty in breathing
- Poor coat condition
- Pale mucous membrane
Diagnosis and Treatment
The diagnosis of this condition begins with a physical examination, that often reveals swollen lymph nodes or swelling of the gastrointestinal tract. Other tests that are carried out for the accurate diagnosis of this cancer are, complete blood cell count test, chemistry panel, X-rays and ultrasound of the internal organs, and fine needle aspiration or biopsy.
Chemotherapy is usually used for treating this cancer. The chemotherapy drugs that are generally used for this condition are, cyclophosphamide, prednisone, doxorubicin, and vincristine. When the tumor is localized, It can be treated with radiation therapy as well. Similarly, surgery and laser treatment can also be carried out, if the tumor is localized to a particular site. Immunotherapy is another treatment option available for treating this cancer.
The prognosis of this cancer depends on the stage at which it is detected, as well as the location of the tumor. It also depends on the type of lymphoma. Usually, the prognosis is better for the low-grade lymphoma, as compared to the high-grade form of the disease. The prognosis has been found to be good for the young cats. But cats with feline leukemia virus and feline immunodeficiency virus have shown poor response to cancer treatment, and the survival rate is also low for them.
In general, cats with this cancer can survive up to 4 to 6 months with proper treatment, while some can experience a remission for a period of 2 or more years, which however is not very common. The symptoms of this cancer are not very specific, which often makes it difficult to diagnose the condition in the early stage. So, pet owners should remain vigilant against the disease, and report any kind of health problems, especially unexplained weight loss, loss of appetite, and persistent diarrhea and vomiting in their cats to a veterinarian. This can help rule out the possibility of serious conditions like lymphoma. Also important is to protect your cats from the feline leukemia and feline immunodeficiency virus with vaccination.
Disclaimer: This article is for informative purposes only, and should not be treated as a substitute for the medical advice of a veterinarian.