Complete Response (CR): Requires all of the following:

Disappearance of all enhancing measurable and non-measurable disease sustained for at least 4 weeks. The first scan exhibiting disappearance of all enhancing measurable and non-measurable disease is considered “preliminary CR”. If the second scan exhibits measurable enhancing disease with respect to the “preliminary CR” scan, then the response is not sustained, noted as pseudoresponse, PsR, and is now considered “preliminary PD” (note confirmed PD requires at least two sequential increases in tumor volume). If the second scan continues to exhibit disappearance of enhancing disease or emergence of non-measurable disease (less than 10mm bidimensional product), it is considered a durable CR and the patient should continue on therapy until confirmed PD is observed. Patients must be off corticosteroids (or on physiologic replacement doses only). Stable or improved clinical assessments (i.e. neurological examinations). Note: Patients with non-measurable disease only at baseline cannot have CR; the best response possible is stable disease (SD).

The disappearance of all signs of cancer in response to treatment. This does not always mean the cancer has been cured. Also called complete remission.