Incidence of multiple myeloma in Great Britain, Sweden, and Malmö, Sweden: the impact of differences in case ascertainment on observed incidence trends.

OBJECTIVES The increased incidence of multiple myeloma (MM) across China and East Asia stimulated us to examine the current rates in Great Britain, where rates increased dramatically in the second half of the 20th century. However, rates have been stable and high during this period in Malmö, Sweden, where there is a keen interest in MM. We thus assessed recent changes in MM incidence in Great Britain, Sweden overall, and Malmö, Sweden, and examined how these changes might explain recent reports of increased MM incidence across Asia. DESIGN Estimation of MM incidence for Great Britain, Sweden overall, and Malmö, Sweden. POPULATIONS MM incidence data for Great Britain (1975-2009) were obtained from Cancer Research UK and for Sweden (1970-2009) from the Swedish Cancer Registry. MM incidence data from Malmö, Sweden, were available from 1950 to 2012. MAIN OUTCOME MEASURES Age-specific incidence of MM in Great Britain, Sweden overall, and Malmö, Sweden. RESULTS MM incidence in Great Britain, Sweden overall, and Malmö increased progressively with age, even among the oldest group. The MM age-adjusted incidence (European standard population) increased by 69% from 1975-1979 to 2005-2009 in Great Britain, from 3.2/100,000 to 5.4/100,000. The largest increases occurred among those 70-79 years of age, for whom rates increased from 17.9/100,000 to 33.6/100,000; reflecting an increase of 69%. During this same period, the age-adjusted incidence (European stand population) in Sweden overall remained stable, at approximately 4.7/100,000. CONCLUSIONS MM age-specific incidence is now similar in Great Britain, Sweden overall, and Malmö. We believe this is a result of improvements in case ascertainment in Great Britain, particularly among the elderly. Similar changes can be predicted to occur across Asia as improved access to healthcare contributes to better diagnosis of MM.