Lymph node cancer, also known as lymphoma, is a condition that affects over 10% dogs with cancer. The lymph node cancer can be primary (it originates in this organ) or can be secondary, originating in other areas of the body and extending to the lymph nodes. The condition is more common in dogs over the age of 5 and some dog breeds display this type of cancer more frequently than others.
Causes of Lymph Node Cancer
As with any other types of canine cancer, the causes of lymph node cancer are not entirely understood.
The possible causes of lymph node cancer may include:
- Exposure to various toxic environmental factors (i.e. pesticides and other chemicals)
- The dog’s diet
- Genetic factors
Symptoms of Lymph Node Cancer
The lymph node cancer may be primary, when the tumor affects the lymph nodes. The tumor may also occur in other areas of the body and can metastasize in the nearby lymph nodes. Depending on the point of origin of the tumor, the dog may present various symptoms.
The symptoms that will be common, regardless of the origins of the malignant tumor include:
- Inflamed lymph nodes – the lymph nodes can be palpated at the base of the neck or in the front area of the shoulders
- Lethargy and lack of activity
- Hiding behavior
- Vomiting and diarrhea
- Lack of appetite and weight loss
- Breathing problems
Watch out for all symptoms and let the vet know, as these symptoms will help in the diagnosis.
Diagnosis for Lymph Node Cancer
The lymph node cancer can be diagnosed using the following tests:
- Complete blood count
- X-rays, which can show where the tumor is located and whether the cancerous cells have spread from other organs to the lymph nodes
- Lymph nodes aspirated
- Bone marrow testing
- Biopsy of a sample from the tumor
Treatment Options for Lymph Node Cancer
The treatment options will depend on the stage of the cancer. There are 5 stages of lymphoma:
- Stage 1 lymphoma, when there is a single tumor affecting one lymph node. At this stage, the tumor should be removed through surgery
- Stage 2 indicates that the tumors affect several lymph nodes in 1 area. Surgery is still an option
- Stage 3 lymphoma is when all peripheral lymph nodes are affected. At this stage, surgery may be still an option, but bears more risks and chemotherapy may be preferred
- Stage 4 involves other organs such as the liver or lungs. Surgery is no longer an option, but chemotherapy and radiation therapy may be applied
- Stage 5 is when the bone marrow is also affected by cancerous cells and the treatment is limited to pain killers and radiation therapy
Prognosis for Dogs with Lymph Node Cancer
When detected in stages 1 to 3, the tumors may be removed through surgery and the dog’s prognosis is positive. The tumors may grow back, but not in all cases.
When detected during stage 4 or 5, the dog will need support therapy and may survive for up to 6 months.