T-cell lymphoma in cats is a cancer originating from T-lymphocytes, white blood cells crucial to the immune system. These cells normally circulate, protecting against infections. When T-lymphocytes grow uncontrollably, they form tumors in various organs. This is a frequently diagnosed cancer in felines.
Common Forms and Associated Symptoms
T-cell lymphoma affects cats in various locations, each presenting distinct signs. The gastrointestinal (GI) form is most frequent, often causing chronic digestive upset. Cats with GI lymphoma may experience persistent vomiting, diarrhea, weight loss, and decreased appetite. An abdominal examination might reveal thickened intestines or a palpable mass.
Mediastinal lymphoma develops in the chest cavity, typically involving the thymus gland or lymph nodes. Cats with this form often show respiratory distress, such as difficulty breathing, coughing, or open-mouth breathing, due to a mass compressing the lungs and airways. This type is more common in younger cats and strongly associated with Feline Leukemia Virus (FeLV).
Less common forms include cutaneous lymphoma, appearing as skin lumps or lesions. Nasal lymphoma affects the nasal cavity, causing chronic sneezing, nasal discharge, and sometimes swelling on the nose bridge. Renal lymphoma involves the kidneys, with signs similar to kidney disease, including increased thirst, urination, weight loss, and vomiting.
The Diagnostic Pathway
Diagnosis begins with a thorough physical examination. During this assessment, the veterinarian might palpate for enlarged lymph nodes or abdominal masses, suggesting a tumor. Blood tests, including a complete blood count and chemistry panel, assess organ function, detect anemia, or identify elevated calcium levels, which can be associated with lymphoma.
After blood work, imaging studies visualize tumors and assess disease extent. X-rays of the chest or abdomen can reveal masses or fluid, particularly in mediastinal or abdominal lymphoma cases. Abdominal ultrasound provides a detailed view of internal organs, detecting thickened intestinal walls, enlarged lymph nodes, or masses in organs like the liver or spleen.
A definitive diagnosis requires a tissue sample for microscopic examination. Fine needle aspiration (FNA) is often the first, less invasive step, collecting cells from a suspicious area for cytological analysis. While FNA provides a preliminary indication, a surgical biopsy is the gold standard for a conclusive diagnosis, allowing a larger tissue sample for pathologist evaluation. This biopsy differentiates between T-cell and B-cell types and determines tumor grade, guiding treatment.
Standard Treatment Approaches
Chemotherapy is the primary treatment for most T-cell lymphoma forms, especially when systemic or involving multiple organs. This approach uses specialized drugs to target and eliminate rapidly dividing cancer cells. Multi-agent chemotherapy protocols, such as CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisolone), are frequently used for aggressive forms.
Chemotherapy schedules often involve regular weekly or bi-weekly veterinary visits for drug administration. Cats generally tolerate chemotherapy better than humans, with less common and milder side effects. Potential side effects, occurring in about 10% of patients, may include temporary vomiting, diarrhea, decreased appetite, or whisker loss, but these are often manageable with supportive medications.
Radiation therapy is another treatment option, effective for localized tumors like nasal lymphoma. This therapy uses high-energy radiation to shrink or destroy cancer cells in a specific area. Advanced techniques like stereotactic radiation therapy can deliver precise, high doses to the tumor while minimizing exposure to healthy tissues.
Steroids, such as prednisolone, also help manage T-cell lymphoma. These medications reduce inflammation associated with tumors and temporarily improve a cat’s symptoms, enhancing well-being. Steroids may be used for palliative care to enhance comfort or as part of a broader chemotherapy regimen to improve effectiveness.
Prognosis and Palliative Care
The prognosis for cats with T-cell lymphoma varies significantly, influenced by tumor location, overall health, and treatment response. T-cell lymphoma often carries a more guarded prognosis than B-cell lymphoma. Without treatment, survival time is typically short, often four to six weeks.
With appropriate treatment, remission (where cancer signs disappear) is achievable for many cats. For low-grade gastrointestinal T-cell lymphoma, oral medications like chlorambucil and prednisolone can lead to an average remission of two to three years. More aggressive, high-grade forms, even with multi-agent chemotherapy, tend to have shorter remission times (two to nine months) and an average survival of six to nine months.
Mediastinal lymphoma in FeLV-positive cats often has a poorer outlook, with an average survival of three months. FeLV-negative cats with this form may live nine to twelve months with treatment. Nasal lymphoma, treated with radiation therapy, can have a more favorable prognosis, with some cats living one to two years. Regardless of prognosis, maintaining the cat’s quality of life is a significant focus.
Palliative care focuses on managing symptoms and ensuring the cat remains comfortable with lymphoma. This approach addresses nausea, pain, and appetite loss to support the cat’s well-being. Even if aggressive chemotherapy is not chosen or effective, supportive measures, including steroids, can alleviate discomfort and provide a peaceful existence.