Bone metastases in breast cancer: Frequency, metastatic pattern and non-systemic locoregional therapy.

Background: The study evaluates the frequency of and indications for bone-metastases (BM)-related surgery and/or radiotherapy in the palliative breast cancer (BC) situation and analyzes in which phase of the palliative disease course surgery and/or radiotherapy was applied.
Methods: 340 patients who developed distant metastatic disease (DMD) and died (i.e. patients with completed disease courses) were analyzed.
Results: From the entire study cohort, 237 patients (69.7%) were diagnosed with BM. Out of these, 116 patients (48.9%) received BM-related radiotherapy and/or surgery during the palliative situation.
Radiotherapy: 108 patients (45.6%) received 161 series (range: 1-5) with 217 volumina (range: 1-8) on 300 osseous sites. At 75.3% of the radiated sites, the spine was the most frequent radiated location. Eighty-eight series (54.7%) were performed in the first third of the metastatic disease survival (MDS) period. The median survival after radiotherapy was 14 months (range: 0.2-121 months).
Surgery: In 37 patients (15.6%), 50 procedures (range: 1-4) were necessary to stabilize BM. The femur predominated with 56.0% of the procedures. Twenty procedures (40.0%) were performed in the first third of survival follow-up. The median survival after surgery was 13.5 months (range: 0.5-49 months). BC patients with BM had a significantly improved MDS when radiotherapy and/or surgery for skeletal metastases was embedded in the palliative approach (27.5 months vs. 19.5 months, p<0.001). From the 118 patients who had a MDS of ≥24 months, the majority (54.2%) had BM-related radiotherapy and/or surgery during the palliative course.
Conclusions: Metastatic BC has become increasingly viewed as a chronic disease process. In a general palliative therapy approach, which allows for treatment according to the principles of a chronic disease, non-systemic therapy for BM, in particular radiotherapy, has a clearly established role in the therapy concept.