Abstract / Summary
Summary: Background: Norway has one of the world's highest melanoma incidence rates. Despite preventive efforts, their long-term impact remains unclear. We examined sex- and age-specific melanoma trends in Norway. Methods: We used nationwide Cancer Registry data on first primary melanoma in Norway during 1980–2024. Incidence rates were age-standardised to the European Standard Population 2013. Joinpoint regression estimated average annual percentage changes (AAPCs) with 95% confidence intervals (CIs), by sex, age, region, anatomical site, and subtype. Age-period-cohort analyses assessed temporal patterns. Findings: Among 60,722 individuals with melanoma, 29,775 (49.0%) were male. Overall, incidence increased by 2·4–2·7% yearly in 1980–2024 in both sexes. Trends diverged, with stable or declining incidence among younger individuals and continued increases exceeding 5% [5·2, 6·6] in the oldest groups. Birth-cohort analyses identified a strong birth-cohort effect, with progressively increasing incidence across successive older birth cohorts, whereas younger cohorts showed stable or declining incidence. Northern Norway had the largest regional increases (AAPC 4·6 [3·8, 5·3] in males and 3·1 [2·5, 3·8] in females). Incidence increased particularly on the head and neck in men and the trunk and upper limbs in women. Superficial spreading melanoma showed the strongest increase among subtypes (4·1 [3·7, 4·6] and 3·1 [2·8, 3·5], respectively). Interpretation: Melanoma incidence in Norway continues to rise mainly among older adults, while trends in younger generations are stabilising or declining. Cohort patterns and regional differences are consistent with potential changes in UVR-related behaviours. These findings support the need for targeted prevention strategies for groups with persistently increasing incidence. Funding: None.