Relapse from Complete Response of Multiple Myeloma or Plasma Cell Leukemia

**Semantic type:** Finding

**Definition:** Relapse from complete response of multiple myeloma or plasma cell leukemia requires one or more of the following: reappearance of serum or urine M-protein by immunofixation or electrophoresis; development of 5% or more plasma cells in the bone marrow (relapse from complete response has a 5% cutoff vs.10% for other categories of relapse); appearance of any other sign of progression (e.g., new plasmacytoma, lytic bone lesion, hypercalcemia). Relapse requires two consecutive assessments made at any time before classification as relapse, and/or the institution of any new therapy.