OBJECTIVES: To update the knowledge on therapeutic practices and survival of newly diagnosed breast cancer (BC) patients, this study describes the incidence, initial treatment, and survival in German females.

METHODS: Claims data of 1.1 to 1.2 million female members over 18 years in a German statutory health insurance fund (AOK PLUS) from 2010 to 2020 were retrospectively analyzed. Individuals who had at least one inpatient and/or two outpatient diagnoses of BC (ICD-10 code C50) between 2013 and 2019 were identified. A case was considered being incident if there was a diagnosis-free and BC-treatment-free period of at least 36 months. Patients who were not continuously insured during the 36-month pre-diagnosis period were excluded. Treatment data were considered until the end of the study period (31/12/2020). The age-adjusted cumulative incidence was calculated. The time-to-treatment initiation (TTI) and overall survival were estimated by Kaplan-Meier analysis. The first outpatient or inpatient BC treatment after diagnosis, including surgery, radiation, and systemic therapies, was considered the initial therapy.

RESULTS: We identified 17,893 incident cases (median age: 69 years). The yearly age-adjusted cumulative incidence was 0.17%. The survival probability at 5 years after diagnosis was 70.8% (95%-CI: 70.0% - 71.5%). The latter was higher in patients aged below 65 years (90.0%, 95%-CI: 89.2% - 90.8%). The median TTI was 1.14 months (95%-CI: 1.11 – 1.15). Overall, 80.1% of cases received initial treatment within the three months after diagnosis, including surgery (52.5% breast-conserving surgery and 19.0% mastectomy), antineoplastic agents (13.7%), and endocrine therapy (8.5%).

CONCLUSIONS: With a yearly cumulative incidence of 0.17% in females, BC remains a considerable burden in Germany. The median onset age highlighted that the affected population consists of elderly patients having a higher risk of relevant comorbidities, making the treatment management more complex. Nevertheless, a reasonable TTI was observed in this study.