Aims: To report the effect on outcome of selection in patients receiving intra-operative electron beam radiation (IOERT) and external beam radiation therapy (EBRT). Methods: One hundred and three patients treated for primary RS were studied. Median follow-up was 27 months. Clinical presentation, tumor characteristics, and treatment methods were analyzed to determine impact on survival and recurrence and if selection was occurring. Results: Mean age was 55 ± 17 years. Mean tumor size was 15 ± 6 cm and 88 were high-grade. Complete gross tumor resection (CR) occurred in 62 patients and improved survival vs. both debulking (p = 0.0005) and biopsy (p < 0.0001). The 5- and 10-year survival rates were 62% and 52% for those with CR vs. 29% and 20% after incomplete resection. Among the 62 CR patients, there was selection to receive additional EBRT ± IOERT in patients with high-grade tumors (p = 0.005) and/or microscopically positive margins (p = 0.011). In these high-risk patients there was a trend for IOERT to further augment survival vs. EBRT alone and to increase the time to both local and distant recurrences (p = 0.036). Conclusions: Complete gross resection is the primary form of curative treatment for retroperitoneal sarcomas. Selection led to patients with high-risk tumors receiving additional radiation therapy. There appears to be a beneficial effect of IOERT plus EBRT in these high-risk patients after complete tumor resection.
Bibliographical noteFunding Information:
The authors thank the staff of the MGH cancer registry for their help in collecting data for this study and Ms M. Mulder for excellent data processing. Support from the Niels Stensen Foundation, The Netherlands, is gratefully acknowledged.
- Intra-operative radiation therapy