Assessment of the Effect of Migration on Melanoma Incidence Trends in Australia Between 1982 and 2010 Among People Under 30

Sir, In this journal, it has been suggested (1) that the incidence of invasive melanoma among susceptible young Australians is increasing, not decreasing as several other recent studies have noted (2–4). The argument presented was that previous analyses have used the total population as the denominator for the calculation of rates, not the susceptible population, and thereby people who are at low risk of melanoma have been incorrectly included. With the increased migration into Australia of people born in “low risk” countries (for melanoma) such as Asia, Middle East and the Pacific Islands, Czarnecki (1) provided data to suggest that the inclusion of these migrants in the denominator artificially reduced the observed incidence rates of melanoma, thereby hiding the proposed real increase in melanoma. Population trends in melanoma incidence rates are obtained using data collected through cancer registries. While these registries do collect information on country of birth, these data are typically not complete. Thus any examination of the role of country of birth on melanoma incidence rates will be subject to certain assumptions. Due to the concerns that have been raised (1), we felt that it was important to re-examine this issue further through the use of a simulation study, and discuss the ramifications for ongoing cancer control in Australia