gms | German Medical Science

Background: Complete surgical resection remains the mainstay of treatment of soft tissue sarcomas (STS) located in the retroperitoneal space, but is possible only in 60-70% even in patients presenting with primary disease. Randomized trials have demonstrated improved local tumor control for patients with extremity STS after postoperative radiotherapy (EBRT) whenever doses of 60-70 Gy can be administered. As EBRT in retroperitoneal STS is limited by tolerance doses of surrounding tissues, additional IOERT was used to overcome these dose limitations.

Methods: From 1991 to 2004, 67 patients with retroperitoneal STS (primary disease 39 %, recurrent disease 61 %) were treated with maximal resection, IOERT and EBRT. Median age was 54 years. 67 % of the patients showed high grade (G3) tumors, the mean tumor size was 11 cm and the most common histology was liposarcoma (51 %). We delivered a median IOERT dose of 15 Gy with electron energies ranging from 8 to 15 MeV to the complete tumor bed if possible. Postoperative EBRT was given to 67 % of our patients with a median dose of 41,4 Gy in 1,8 Gy per fraction by linear accelerator with photon energies ranging from 6 to 23 MV after CT-based 3D treatment planning.

Results: Median follow up was 21 months. Complete resection was possible in 21 (31%) patients, while 34 patients (51%) showed microscopically, and 12 (18%) patients macroscopically residual disease. The 1-, 2- and 5-year actuarial overall survival rates were 91%, 81% and 58%. Only resection status had significant impact on survival. After complete resection, 5 year actuarial survival was 85% compared to 45% after R1/2 resection. 1-, 2- and 5-year locoregional control rates were 78%, 62% and 30%. The 5-year actuarial local control rate inside the IOERT field was 54%. Locoregional control was significantly affected by resection status and grading. For the 12 patients who completed IOERT and EBRT after R0-resection, 5- and 10- year actuarial survival was 80%, and 5- and 10-year locoregional control was 100%. Except for 5 patients with postoperative wound healing disturbances, no IOERT related acute complications were seen. Only 2 patients required surgical interventions due to late complications.

Conclusion: Combination of maximal surgical resection, IOERT and EBRT in patients with retroperitoneal sarcomas results in good overall survival, especially in R0 resected patients, without increased toxicity to normal tissue.