The Undetermined Significance of Screening for Monoclonal Gammopathy of Undetermined Significance.

The identification of premalignant lesions in solid tumors such as colorectal and cervical cancer has led to the development of highly effective population-wide screening programs for these malignancies. Although precursor clinical states are not well-established for most hematologic malignancies, multiple myeloma is a notable exception. Virtually all patients with multiple myeloma first develop monoclonal gammopathy of undetermined significance (MGUS), an asymptomatic but easily detectable condition. However, broad screening for MGUS has not been adopted primarily because there is no proven intervention to delay or prevent the progression of MGUS to multiple myeloma. Furthermore, the incidence of MGUS is poorly understood; a better understanding of its epidemiology will be critical in designing appropriate screening guidelines once an effective treatment has been developed. In the current issue of Cancer Epidemiology, Biomarkers & Prevention, Ji and colleagues provide important epidemiologic insights on MGUS, including a critical discussion on how its incidence and preclinical duration vary by age and race, acknowledging that both MGUS and multiple myeloma are more common in Black than White populations. See related article by Ji et al., p. 1690.