[Intraoperative radiotherapy within the treatment concept of retroperitoneal soft tissue sarcomas]

Sarcomas of the retroperitoneum are characterized by a high rate of local recurrence. External beam radiotherapy is known to improve local control after surgical therapy. To increase local dosage of radiotherapy without affection of sensitive structures we applied intraoperative radiotherapy (IORT) since 1991 in a dedicated operative unit. To compare morbidity and tumor control we used a partly historic control group of patients treated since 1988 for retroperitoneal soft tissue sarcoma. 25 patients with a mean age of 53 years were operated. Tumor histology was dominated by liposarcoma and leiomyosarcoma, UICC stage IIB (T2 G2 N0 M0) was present in 45% of cases. Distant metastasis were diagnosed in 19% at therapeutic intervention. Tumor free margins were achieved in 55% while 29% showed microscopic and 16% macroscopic tumor residues after surgical intervention. 11 patients received IORT with a mean of 18 Gy, eight of those patients were treated additionally with a mean of 40,4 Gy externally. There were no differences in distribution of known risk factors for recurrence in the group of patients treated with or without IORT. The analysis showed no difference for perioperative morbidity. Tolerance for IORT and additional external beam radiotherapy was good. Local tumor control tended to be improved by IORT (p = 0.082) while overall survival was not affected at a mean follow-up of 24 months.