Recognizing the First Symptoms of Canine Lymphoma
Lymphoma is a common form of cancer in dogs that affects the lymphocytes — a type of white blood cell crucial to the immune system. This disease can affect nearly any part of a dog's body, including the lymph nodes, spleen, liver, bone marrow, and gastrointestinal tract.
The First Sign of Trouble
The earliest and most common symptom of multicentric lymphoma, the most prevalent form of this cancer, is the noticeable swelling of lymph nodes. These swellings are usually firm, painless, and non-tender to the touch. Owners may first detect them under the jaw, in front of the shoulders, behind the knees, in the armpits, or in the groin area.
At this initial stage, affected dogs may appear entirely healthy, remaining active and alert, although some can show mild signs such as tiredness or decreased appetite.
Types of Lymphoma and Their Symptoms
- Multicentric Lymphoma: Accounts for 80–85% of cases. Symptoms start with enlarged lymph nodes, later progressing to affect other organs, causing lethargy, vomiting, or weight loss.
- Alimentary (Gastrointestinal) Lymphoma: Starts in the digestive tract, leading to vomiting, diarrhea, and weight loss. Less likely to have enlarged lymph nodes initially.
- Mediastinal Lymphoma: A rare type seen in the chest cavity. Symptoms may include breathing difficulties and facial swelling.
- Extranodal Lymphoma: Involves areas outside traditional lymph sites, such as the skin (cutaneous lymphoma), eyes, or bones. Skin lesions and localized effects depending on the organ involved are typical.
Stages and Substages of Canine Lymphoma
Veterinarians classify lymphoma into five stages based on how far the cancer has spread:
- Stage I: A single lymph node is affected.
- Stage II: Multiple lymph nodes on one side of the diaphragm.
- Stage III: Generalized lymph node involvement.
- Stage IV: Spread to the liver and/or spleen.
- Stage V: Involvement of bone marrow, blood, or the central nervous system.
These are further differentiated by:
- Substage A: No other clinical symptoms beyond lymph node swelling.
- Substage B: The dog is ill and exhibiting clinical signs.
Diagnosis and Detection
If swollen lymph nodes are observed, prompt veterinary evaluation is essential. Vets may use:
- Fine Needle Aspiration (FNA): A simple test that samples cells from the lymph nodes.
- Biopsy: A more conclusive test when FNA is inconclusive.
- Blood work and imaging: To analyze internal involvement and rule out metastasis.
Treatment and Outcomes
Chemotherapy is the mainstay for treating lymphoma, often yielding remission in 80–90% of multicentric cases. The CHOP protocol is the most effective. Other options include:
- Oral medications like lomustine for skin lymphoma types.
- Radiation or surgery for localized types, though used less often.
- Prednisone for palliative care when chemotherapy isn’t pursued.
Most dogs tolerate chemotherapy well, with minimal side effects, and often enjoy a good quality of life while in remission.
Prognosis and Monitoring
With treatment, average survival extends to 9–12 months, sometimes longer. Without treatment, life expectancy drops to only a few weeks. Periodic checkups help detect relapse early, increasing chances for renewed remission using adjusted treatment strategies.
Key Takeaway
Firm, swollen, non-painful lymph nodes are usually the earliest and most visible sign of lymphoma in dogs. Prompt medical attention and early intervention significantly improve outcomes. If you notice any unexplained lumps on your dog’s body, especially in typical lymph node locations, consult your veterinarian without delay.
