What are recurrent tumors?

"Relapse" Cancers that are treated can recur in one of two general ways locally or systemically. A local recurrence can often be retreated with surgery or radiotherapy. Systemic recurrence with tumor developing in distant organs is often managed with chemotherapy.
Treated / back now. Once treated and in remission for a period of time, but found to have come back. Typically a biopsy is performed to document recurrence.