Clinical outcome of patients with soft tissue sarcoma after bone metastases: Tokai musculoskeletal oncology consortium study.

Background: Soft tissue sarcomas (STSs) are a diverse group of rare malignant tumors accounting for <1% of all human tumors. Almost 50% of patients with STS develop metastatic disease, mainly within 3 years of initial diagnosis. Lung metastasis occurs in 20%-30% of STS cases, while bone metastasis is rare.

Patients And Methods: We investigated tumor characteristics and clinical outcomes in 59 patients with STS who developed bone metastases.

Results: A total of 21 patients had solitary bone metastasis: two in the extremity, 11 in the vertebral body, and eight in the trunk. Around 38 patients had multiple bone metastases: 18 with extremity bone involvement and 20 with no extremity bone involvement. Fourteen patients developed complicated bone metastases with distant extrapulmonary metastases. Seven patients had no distant metastases other than bone; that is, the bone was the first distant metastasis. The 5-year disease-specific survival (DSS) rate after primary treatment was 45.1%. The median 5-year DSS after bone metastasis was 28.1 months. The 5-year DSS rate was 55.6% in nine patients who underwent radical local treatment for solitary bone metastases. The 5-year DSS rate was 14.7% in 50 patients who did not undergo local radical treatment for bone metastases, with a significant correlation.

Conclusion: Patients with bone metastases from STS had a relatively good prognosis after bone metastases. Solitary bone metastases can be aggressively treated. Although nearly half of the patients received bone-modifying agents, the effectiveness of these therapeutics warrants further investigation.