How long can a dog with a mammary tumor live?

Whether a mammary tumor affects lifespan depends on the tumor’s nature and treatment. A benign tumor is generally curable by timely surgery and will not affect lifespan. A malignant tumor may recur after surgery, and once it recurs or metastasizes, the prognosis is poor; in severe cases the dog may have only months left, so lifespan depends on disease severity.