Canine lymphoma is highly treatable with chemotherapy, and modern protocols maintain quality of life while significantly extending survival.
Lymphoma causes rapid deterioration without treatment - lethargy, lymph node enlargement, anorexia, and organ infiltration. The welfare transformation from treatment can be dramatic: dogs entering complete remission quickly regain normal activity and quality of life. Modern chemotherapy protocols cause minimal toxicity in most dogs - vomiting and lethargy occur in 25-30% but are usually mild and transient. The welfare calculation strongly favors treatment for medically eligible dogs whose owners can commit to the protocol.