Metastatic Breast Cancer: Prolonging Life in Routine Oncology Care

Simple Summary Breast cancer patients whose tumor has already developed metastases are now living longer and longer in studies. These results are encouraging but must be viewed with caution because study participants are in most cases very special, i.e., they are younger or have fewer concomitant diseases than the average patient. For this reason, we analyzed all patients who were diagnosed with metastases between 1995 and 2022. The analysis showed that survival has also improved continuously in this real-world patient group. In a comparison of the periods 2018-2022 vs. 1995-2000, patients live about 1.5 years longer, a total of approximately 48 months.Abstract Overall survival (OS) of patients with metastatic breast cancer (MBC) has improved within controlled clinical trials. Whether these advances translate into improved OS in routine care is controversial. We therefore analyzed retrospectively unselected female patients from five oncology group practices and one university outpatient clinic, whose initial diagnosis of MBC was between 1995 and 2022. A total of 1610 patients with a median age of 63 years (23-100) were evaluated. In all, 82.9% had hormone-receptor-positive disease, and 23.8% were HER2-positive. Evaluation in time cohorts by initial MBC diagnosis date showed a continuous prolongation of median OS from 31.6 months (0.5-237.3+) (1995-2000) to 48.4 months (0.4-61.1+) (2018-2022) (p = 0.003). Univariable analyses showed a significant dependence on the time cohort of diagnosis, metastatic status at initial diagnosis, age at metastasis, hormone and HER2 status, general condition, metastasis localization, and the number of affected organs. A multivariable analysis revealed a significant dependence of survival probability on receptor status, general condition, and number of metastatic sites, as well as the time between initial breast cancer diagnosis and the diagnosis date of MBC in months. In sum, OS of patients with MBC has improved continuously and significantly in routine care over the last 27 years.