A year-end update1 on Waldenström macroglobulinemia (WM), a distinct entity of lymphoplasmacytic lymphoma presenting with monoclonal pleomorphic immunoglobulin M (IgM) proteins,2 has been published in the American Journal of Hematology.
The incidence of WM has not changed over the past 50 years, persisting at a relatively low rate (0.57 per 100,000 person-years) and occurring more frequently among men (0.92 vs 0.30 per 100,000 person-years) at a median age of 71 years.3
Diagnosing Waldenström Macroglobulinemia
Arriving at a diagnosis of WM may be difficult, as the symptoms can be confounded by similarly presenting diseases such as marginal zone lymphoma4 or IgM multiple myeloma.5 A diagnosis of WM is thorough and involves serum protein electrophoresis; b2-microglobulin evaluation and viscosity testing; evaluation of IgM, IgG, and IgA; identification of monoclonal light chains in urine; biopsy of bone marrow; cytogenetic assessment; computed tomography of the abdomen and pelvis; and assessment for amyloid deposits.
The typical disease course among patients with WM has a preliminary asymptomatic phase that can last for several years. In a communication, Morie A. Gertz, MD, from the Department of Hematology at the Mayo Clinic and author of the manuscript, explained that “the most common error I see in my referral practice is patients are initiated on therapy based on the levels of IgM rather than on symptomatic assessment. In other words, patients are treated prematurely before they really need therapy, when they’re in a smoldering stage.”
During this smoldering stage, before symptoms of tumor mass infiltration present, patients have monoclonal gammopathy of undetermined significance and bone marrow infiltration >10%.1 Following the smoldering stage, patients progress to develop IgM-related disorder that is characterized by symptoms of neuropathy, amyloidosis, cold agglutinin hemolytic anemia, and type II cryoglobulin.1
Before developing a treatment plan, patients should be stratified according to the international staging system for WM,6 which comprises 5 weighted criteria with the most high-risk features defined as age >65 years, hemoglobin concentration £11.5 g/dL, platelet count £100,000/mcL, b2-microglobulin >3 mg/L, and monoclonal IgM >7 g/dL.6
When developing a treatment plan after WM diagnosis and patient stratification, Dr Gertz stressed that clinicians should ensure “therapy is driven by patient symptoms and quality of life, not on some arbitrary numeric threshold.”