1323Trends in the incidence rates of keratinocyte carcinomas from 1978 to 2018 in Tasmania, Australia

Background Keratinocyte carcinomas (KCs), namely basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), are the most common cancers in Australia. We describe trends in the incidence of KCs in the state of Tasmania over 41 years. Methods We identified histologically confirmed KCs within the Tasmanian Cancer Registry. Age-standardised incidence rates were calculated for first (1985-2018) and annual KCs (1978-2018). Average annual percentage changes were computed using Joinpoint regression models. Results A total of 83,536 people were registered with a KC between 1978 and 2018. Age-standardised incidence rates of first KCs increased on average by 3% per annum for BCCs and 4% per annum for SCCs, reaching 363/100,000 and 249/100,000 in 2018, respectively. Age-standardised incidence rates of annual KCs increased on average by 5% per annum for BCCs and 6% per annum for SCCs, up to 891/100,000 and 514/100,000 in 2018, respectively. This increase was steeper for females than males and highest during the late 1980s and early 1990s. A change in trend around 2014 suggested that incidence rates have started to decline. Conclusions While the incidence of KCs in Tasmania increased substantially since 1978, it has recently plateaued and started to decline. The findings may reflect changes in sun exposure behaviours due to awareness campaigns. Key messages Incidence of KCs has increased in 41 years and despite a recent plateau and decline, KCs still pose a substantial burden to the Tasmanian population.