Bone metastases in soft tissue sarcoma: a survey of natural history, prognostic value and treatment options.

Background: We surveyed the natural history of bone metastases in patients affected by soft tissue sarcoma (STS).
Methods: This multicenter retrospective observational study included 135 patients. Histological subtype, characteristics of bone metastases, treatment, skeletal related events (SREs) and disease outcome were recorded.
Results: The most represented histological subtypes were leiomyosarcoma (27%) angiosarcoma (13%) and undifferentiated sarcoma (8%). Axial skeleton was the most common site for bone involvement (70%). In 27% of cases, bone metastases were present at the time of diagnosis. Fifty-four (40%) patients developed SREs and the median time to first SRE was 4 months (range 1-9). The most common SRE was the need for radiotherapy (28%) followed by pathological fracture (22%). Median survival after bone progression was 6 months (range 1-14). SREs were associated with decreased overall survival (OS) (P = 0.04). A subgroup analysis revealed that bisphosphonates significantly prolonged median time to first SRE (5 versus 2 months; P = 0.002) while they did not determine an improvement in OS, although a favourable trend was identified (median: 7 versus 5 months; P = 0.105).
Conclusions: This study illustrates the burden of bone disease from STS and supports the use of bisphosphonates in this setting.