It is uncommon before the age of 40. Without treatment,  the median survival in the prechemotherapy era was about 7 months. After the introduction of chemotherapy, prognosis improved significantly with a median survival of 24 to 30 months and a 10-year survival rate of 3%. Even further improvements in prognosis have occurred because of the introduction of newer biologic therapies and better salvage options, with median survivals now exceeding 60 to 90 months. With current treatments, survival is usually 4–5 years. The five-year survival rate is about 54%. The word myeloma is from the Greek myelo- meaning "marrow" and -oma meaning "tumor". Signs and symptoms
Because many organs can be affected by myeloma, the symptoms and signs vary greatly. Fatigue and bone pain are the most common symptoms at presentation. The CRAB criteria encompass the most common signs of multiple myeloma:: 651 
Calcium: serum calcium >0.25 mmol/L (>1 mg/dL) higher than the upper limit of normal or >2.75 mmol/L (>11 mg/dL)
Renal insufficiency: creatinine clearance <40 mL per minute or serum creatinine >1.77 mol/L (>2 mg/dL)
Anemia: hemoglobin value of >2g/dL below the lowest limit of normal, or a hemoglobin value <10g/dL
Bone lesions: osteolytic lesions on skeletal radiography, CT, or PET/CT

Bone pain
Bone pain affects almost 70% of people with multiple myeloma and is one of the most common symptoms. : 653   Myeloma bone pain usually involves the spine and ribs, and worsens with activity. Persistent, localized pain may indicate a pathological bone fracture. Involvement of the vertebrae may lead to spinal cord compression or kyphosis.
For these people, the standard of care has been chemotherapy with melphalan and prednisone. Recent studies among this population suggest improved outcomes with new chemotherapy regimens, e.g., with bortezomib. Treatment with bortezomib, melphalan, and prednisone had an estimated overall survival of 83% at 30 months, lenalidomide plus low-dose dexamethasone an 82% survival at 2 years, and melphalan, prednisone, and lenalidomide had a 90% survival at 2 years. Head-to-head studies comparing these regimens have not been performed as of 2008.There is support for continuous therapies with multiple drug combinations of antimyeloma drugs bortezomib, lenalidomide and thalidomide as initial treatment for transplant-ineligible multiple myeloma. Further clinical studies are required to determine the potential harms of these drugs and the effect on the persons quality of life. A 2009 review noted, "Deep venous thrombosis and pulmonary embolism are the major side effects of
thalidomide and lenalidomide. Lenalidomide causes more myelosuppression, and thalidomide causes more sedation. Chemotherapy-induced peripheral neuropathy and thrombocytopenia are major side effects of bortezomib. "Treatment of related hyperviscosity syndrome may be required to prevent neurologic symptoms or kidney failure. Maintenance
Most people, including those treated with ASCT, relapse after initial treatment. Maintenance therapy using a prolonged course of low-toxicity medications is often used to prevent relapse. A 2017 meta-analysis showed that post-ASCT maintenance therapy with lenalidomide improved progression-free survival and overall survival in people at standard risk. A 2012 clinical trial showed that people with intermediate- and high-risk disease benefit from a bortezomib-based maintenance regimen.