Abstract
BACKGROUND: Increasing life expectancy increases breast cancer (BC) rates in elderly, where better health allows for improved tolerance of treatments. We assessed trends in BC incidence of tumor subtypes for women with focus on the elderly. METHODS: Changes in BC incidence in women by age from 2012 to 2021 were assessed using data from the Nordic countries. We calculated the incidence of BC subtypes by age group using data from the Danish Breast Cancer Group (DBCG) database. We used generalized linear models assuming a Poisson distribution. RESULTS: In the Nordic countries, 205 305 women were diagnosed with BC between 2012 and 2021. In Denmark, 50 858 BC patients were diagnosed between 2012 and 2022, identified with tumor characteristics. Incidence of BC among women aged 80+ increased significantly across the Nordic Countries, with 1.24 % per year (95 % CI: 0.07 %: 2.41 %). In Denmark, in the 80+ group, the ER+/HER2- subtype had the highest increase, with 1.98 % per year (95 % CI: 1.10 %: 2.87 %). CONCLUSION: Across the Nordic countries, incidence of BC in women aged 80+ increased. In Denmark, rising incidence of BC is driven by the ER+/HER2- subtype in the 80+ group, which has the best prognosis and gentle treatments. More elderly BC patients will require treatment and follow-up in the future.