Dogs without signs of megaesophagus that have their mass completely resected usually have prolonged survival times (>80 percent
one-year survival). Animals with megaesophagus often have very short survival times, and surgery may be contraindicated due
to the morbidity and mortality associated with the procedure, usually related to aspiration pneumonia.
Paraneoplastic syndromes associated with thymoma may or may not resolve with therapy and may occur later in life despite successful
therapy. There have been reports of prolonged survivals in some animals with no therapy for their thymomas, which may indicate
the slow-growing nature of some tumors.