Trend Shifts in Age-Specific Incidence for In Situ and Invasive Cutaneous Melanoma in Sweden

SIMPLE SUMMARY: The incidence of invasive cutaneous melanoma (CM) is increasing in Sweden. The aim was to present age- and sex-specific trends of the age-standardised incidence and the average annual percentage change (AAPC) for in situ and invasive CM by analysing data obtained from the Swedish Melanoma Register and the Swedish Cancer registry for 35,350 in situ tumours and 59,932 CM. Trend shifts in age-specific incidence for in situ and invasive CM reflect a rise among both sexes since the 2000s and could be a result of more effective secondary prevention efforts and a higher awareness of CM. ABSTRACT: Background: The incidence of invasive cutaneous melanoma (CM) is increasing in Sweden. The aim was to present age- and sex-specific trends of the age-standardised incidence and the average annual percentage change (AAPC) for in situ and invasive CM. Methods: Joinpoint regression models were used to analyse data from the Swedish Cancer Register and the Swedish Melanoma Registry 1997–2018 (N = 35,350 in situ CM; 59,932 CM). Results: The AAPC of CM for women was 4.5 (4.1–5.0; p < 0.001) for the period 1997–2018. For men, the APCC was 4.2 (3.0–5.4; p < 0.001), with a significantly higher annual percentage change (APC) for the period 2000–2018 (5.0; 4.6–5.4; p < 0.001) compared to 1997–1999. An increasing annual incidence of CM ≤ 0.6 mm and 0.7 mm Breslow tumour thickness was found for men with a significant incidence shift for the period 2006–2015, respectively. Similarly for women, with a significantly higher APC for CM ≤ 0.6 mm from 2005. The incidence of intermediate thick CM (2.1–4.0 mm) has not increased since 2011. The incidence of CM > 4.0 mm has been increasing among both sexes, with a significantly lower APC among women from 2005. Conclusions: The incidence of in situ and low-risk CM ≤ 1.0 mm in tumour thickness has been rising among both sexes since the 2000s.