Many years can go by before the results of a clinical trial become available.

In many trials, the researchers will want to know how effective the treatment has been. If the cancer has stopped growing, has gotten smaller, or has disappeared, it is known as a response. You may hear your doctors talking about a complete response, partial response, or stable disease.

• Complete response - all the cancer has disappeared. It is normally not considered to be cured until several years have passed.
• Partial response - the cancer has reduced in size by at least 30%.
• Stable disease - the cancer has reduced in size by less than 30%.

Other trials look at long-term side effects or how long people live for after their treatment.