Changes in the incidence of early-onset breast cancer in Germany between 2010 and 2022.

Purpose: The aim of this study was to identify the mean age at which breast cancer (BC) was first diagnosed in 2010 or 2022, and to evaluate whether there were any changes in age groups at first BC diagnosis.

Methods: This retrospective cross-sectional study included adult women (18 years or older) who were diagnosed with BC (ICD-10: C50) for the first time in 2010 or 2022 in office-based practices in Germany (in 300 general practices or 95 gynecological practices). We examined the mean age at diagnosis and the percentage of patients in three age groups (18-49, 50-65, and > 65) for both 2010 and 2022. The average age difference between 2010 and 2022 was analyzed using Wilcoxon rank tests, and the proportions of the three age groups were analyzed using chi-squared tests. These analyses were performed separately for patients in general and gynecological practices.

Results: The mean age at which BC was initially diagnosed in 2022 was found to be significantly greater than that in 2010 for both general practices (66.9 years vs. 64.0 years p < 0.001) and gynecological practices (62.2 years vs. 60.3 years, p < 0.001). Early-onset BC decreased from 15.6 to 12.0% in general practices and from 23.2 to 18.2% in gynecological practices between 2010 and 2022. The proportion of new BC diagnoses in the age group 50-65 increased from 36.6 to 40.9% in gynecological practices, but did not increase in general practices.

Conclusion: The study found that BC was diagnosed at an older age in 2022 than in 2010. In addition, the proportion of early-onset BC cases decreased, while the proportion of cases in the age group 50-65 increased in gynecological practices in Germany.