About 1 in 7 cases of multiple myeloma diagnosed in the United States are cases of smoldering disease, according to an analysis of data from the National Cancer Data Base, which represents 70% of cancer cases.
The prevalence of smoldering multiple myeloma varied among various socio- and geodemographic subgroups, but overall survival did not, Aishwarya Ravindran, MBBS, of Mayo Clinic, Rochester, Minn., and colleagues reported at the annual meeting of the American Society of Clinical Oncology. “Our results can be used in the future to study the health care impact of SMM,” the researchers wrote in a poster presentation.
Courtesy Wikimedia Commons/KGH/Creative Commons License
Histopathological image of multiple myeloma. Smear preparation of bone marrow aspirate stained with May-Grünwald-Giemsa procedure.
Epidemiologic studies of smoldering multiple myeloma have been limited by the lack of International Classification of Diseases codes specific for smoldering status, the researchers said.
They analyzed 86,327 cases of multiple myeloma, considering socio- and geodemographic subgroups and type of treatment facility. Overall survival was compared for smoldering and active multiple myeloma. The researchers included patients enrolled in the database during 2003-2011; records were examined from the time to initial treatment and they considered reasons for patients not receiving treatment.
Patients who did not require treatment within the first 120 days after diagnosis were considered to have smoldering disease. This group comprised almost 14% of the cases.
The proportion of cases that were smoldering disease did not change significantly during the study period (P = .23 and .34, respectively). Smoldering disease was more likely to be diagnosed among women, black patients, older patients (median age at diagnosis was 67 years), and less educated patients. Smoldering disease was more common in patients with fewer medical comorbidities, those living closer to a treatment facility, and those evaluated for their disease in the Northeast United States. The proportions of cases diagnosed at academic and nonacademic facilities were similar.
The median overall survival for smoldering disease was 63 months; for active disease, 33 months. Overall survival in those with smoldering disease did not differ among the racial groups (P = .27).
The researchers had no financial conflicts.
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