Abstract 866: Changing anatomic site trends of melanoma in the United States among young women

Cutaneous malignant melanoma incidence rates have been increasing among young women in the United States. Given that tan-seeking behaviors have increased ultraviolet radiation exposures in anatomic sites usually covered by clothing, i.e., trunk among women, we further assessed melanoma incidence trends by gender and anatomic site. Case and population data among Whites were obtained from the Surveillance, Epidemiology, and End Results Tumor Registries (SEER 9, 1975-2006). Age-period-cohort models were used to assess age, calendar-period, and birth-cohort effects. Net drift, the sum of linear trends in the period and cohort effects, was used to show differential secular trends due to period and/or cohort effects such as screening, case ascertainment, sun exposure, etc. Longitudinal age trend (LAT), the sum of the linear trends in the age and period effects, was used to show differential age-related biological effects. There were 105,829 melanomas diagnosed from 1975 through 2006 in the SEER 9 Registries. The overall age-adjusted incidence rate (IR) was 17.70 per 100,000, with a male to female incidence rate ratio (IRR) of 1.40 (p