Trends in incidence and survival of cutaneous malignant melanoma in Estonia: a population-based study

Background: Previous studies have shown an increase in the incidence of cutaneous melanoma (CM) in Estonia, but also poor survival in international comparisons, with a significant survival gap between the sexes. The aim of this study was to analyze the time trends in CM incidence and relative survival by age, TNM stage and anatomical subsite among men and women in Estonia. Materials and methods: Data from the Estonian Cancer Registry were used to calculate age-standardized (World) and age-specific incidence of CM in 1995-2013, and five-year relative survival ratios (RSR) for cases diagnosed in 1995-2012 and followed through in 2014. Period hybrid analysis was used to calculate the most recent survival estimates for 2010-2014. Results: Between 1995 and 2013, the age-standardized incidence of CM increased significantly in Estonia among both sexes, at a rate of around 4% per year. Among women, the proportion of trunk melanomas increased from 26% in 1995-1999 to 39% in 2010-2012 and became the most common site. The proportion of stage I cases and T1 tumors increased considerably. Women had more favorable stage distribution and thinner tumors than men. The age-adjusted five-year RSR increased significantly, from 64% in 1995-1999 to 81% in 2010-2014. The latest age-adjusted RSRs were 76% among men and 84% among women. Survival gains were the largest in patients below 50 years, those with head and neck or trunk melanomas, and stage III cancer. Conclusions: The proportion of stage I and T1 cases is lower in Estonia compared with the Scandinavian data and is likely a major contributor to the persisting overall survival deficit in Estonia. The apparent deficit in stage II survival also warrants further investigation. A public health program is necessary in Estonia to raise awareness of CM and to significantly increase early stage diagnosis.