Predicting Progression of Developing Myeloma in a High-Risk Screened Population and General Population

Multiple Myeloma (MM) is a plasma cell dyscrasia characterized by bone marrow (BM) infiltration and lytic bone lesions. Over 30, 000 Americans are diagnosed annually with MM. The estimated US prevalence is rising, and this trend is likely to continue due to improvements in diagnosis and therapy. Despite recent advances in therapy, MM remains a fatal disease with a median survival of 5-10 years and most patients still succumb to disease progression. Although many patients are diagnosed with earlier phases of disease, most patients do not receive treatment until their disease progresses, at which time they have overt end-organ damage. This concept of initiating therapy at the time of symptomatic disease is analogous to initiating therapy in patients with solid tumors only after the development of measurable metastatic disease. It is therefore not surprising that cure is not achieved for most patients with MM.

Recent studies have shown that MM is consistently preceded by MGUS and SMM. The incidence of MGUS is about 3% of the general population aged 50 years. This was through the analysis of a cohort of 77,000 people enrolled in a prospective population-based cancer screening trial that showed that multiple myeloma is consistently preceded by a precursor MGUS state. MGUS progresses to over MM at a slow rate of 1% per year, but in some patients, the risk may be as high as 58% in 20 years. SMM has an annual risk of progression of 10%. The rate of progression of high-risk SMM is as high as 70% in 5 years.

MGUS and SMM are often diagnosed incidentally when a physician orders a serum protein electrophoresis (SPEP) for a differential diagnosis of anemia, bone pain or renal insufficiency. Screening for early cancer detection has been implemented for many cancers including breast cancer (with mammography) and colon cancer (with colonoscopy) with variable success. However, a simple blood test for SPEP can accurately diagnose the presence of a plasma cell dyscrasia, indicating that early detection can identify these precursor conditions. In addition, recent studies have demonstrated that early detection of MGUS can lead to improved overall survival compared to incidental diagnosis of overt myeloma, presumably because these patients are followed more carefully and receive treatment before end-organ damage develops.

Therefore, high-risk populations include individuals with a first-degree relative that has been diagnosed with a plasma cell dyscrasia or other hematologic malignancy.