46 NCCN Guidelines for Patients ® : Multiple Myeloma, 2019 4 Treatment guide Active (symptomatic) multiple myeloma Measuring treatment responses A treatment response is an outcome or improvement caused by treatment. The response is defined by how well treatment is killing myeloma cells and improving the severity of symptoms. The main types of treatment responses are listed below. “Complete” and “partial” responses are often jointly referred to as “response.” Complete response No M-proteins are found in the blood or urine. Less than 5 out of 100 cells in the bone marrow are plasma cells. Partial response The amount of M-proteins in the blood has decreased by at least 50%. The amount of M-proteins in the urine has decreased by at least 90%. Also, there is no increase in the size or number of bone lesions. Stable disease Tests do not show a complete or partial response as defined above or progressive disease as defined below. Also, there is no increase in the size or number of bone lesions. Progressive disease One or more of the following has occurred: at least a 25% increase in the amount of M-proteins in the blood or urine, a 25% increase in the number of plasma cells in the bone marrow, an increase in the size or number of bone lesions, or an increase in calcium levels not explained by other conditions. Clinical relapse One or more of the following has occurred: there are direct signs of cancer growth, signs of organ damage, an increase in the number or size (at least 50% larger) of plasmacytomas or bone lesions, increased calcium levels, an increase in creatinine levels in blood, or a decrease in the number of red blood cells. Relapse from complete response One or more of the following has occurred in a patient who had a complete response: a return of M-proteins in blood or urine, or other signs of myeloma but not meeting the criteria for a clinical relapse or progressive disease shown above.