The use of radiation therapy in combination treatment of soft tissue sarcomas of the extremities with involvement of long tubular bones

Soft tissue sarcomas (STS) are rare malignant tumors of mesenchymal origin. They account for about 1% of all malignant neoplasms. Haematogenous spread is the most common route of metastasis for STS and bone metastases occur in 9.4% of cases. When creating treatment plan for STS, it is necessary to consider a multimodal approach. Combination treatment can include preoperative or postoperative radiation therapy (RT), chemotherapy (CT), and local hyperthermia (LHT). Surgery for STS should be radical. This paper presents 9 STS clinical cases and treatment outcomes in patients with secondary bone disease. Four patients underwent chemotherapy and surgery. Two patients received chemoradiotherapy (CRT) and surgery. Three patients received thermo-chemo-radiotherapy (TCHRT) followed by surgery. Accelerated fractionation radiotherapy was given using a single tumor dose of 3 Gy, twice a day with interval of 4 hours between sessions, 3 times a week to a total tumor dose (TTD) of 30 Gy (isoeffective TTD - 42 Gy, TDF - 69 Gy). Local hyperthermia for soft tissue tumor treatment was performed over 6 sessions: 2 sessions were combined with CHT courses before and after RT, and 4 sessions were combined with RT. The follow up period for 6 patients varied from 12 to 1.5 months, for 3 patients it varied from 6 to 8 months, for 1 patient it lasted 3 months and for 1 patient - 2 years. According to the RECIST criteria, more than half of the patients had tumor stabilization and 22% of patients had a partial response. Grade III-IV the rapeutic pathomorphosis was observed in 70% of patients after preoperative combination treatment. The use of CT, CRT or TCHRT in combination treatment of STS with secondary bone disease enabled us to achieve a pronounced therapeutic pathomorphosis of tumors and to perform organ preservation surgery with endoprosthetic replacement.