After treatment completion, an individual is generally assessed for response after a period of time to allow maximal regression of the tumor. At the end of that period if there is no residual disease that can be identified on clinical examination by the doctor, or on x-rays and scans, or even by lab tests for the disease or its markers it is called complete response (or complete regression).
Complete response (CR) does not imply cure. Some people with a complete response may have a tumor recurrence later. But it definitely is a good thing to have a complete response - it is the best starting point for a cure.
Understand more about other terms used in assessing treatment response in the article How is treatment response described?
