Hyperfractionated 192Ir brachytherapy for recurrent retroperitoneal sarcoma: a technique for delivery of local tumor boost dose.

BACKGROUND: Radical surgery is the treatment of first choice for retroperitoneal sarcoma. However, locoregional relapse is frequently observed leading to death in the majority of patients. The role of radiotherapy is not well defined in the management of retroperitoneal sarcoma. Yet, there is evidence that adjuvant irradiation does improve local tumor control.

MATERIAL AND METHODS: In order to deliver sufficiently high radiation doses to the retroperitoneum, different techniques for application of a local tumor boost dose in addition to external beam treatment have been proposed. We present a technique of hyperfractionated (192)Ir brachytherapy (HFIR) of the tumor bed via intraoperatively implanted plastic catheters. Postoperative CT-based image-guided brachytherapy was performed. In two consecutive patients with recurrent retroperitoneal sarcoma, treatment was delivered twice daily with single doses of 1.5-2.0 Gy in 5-10 mm tissue depth up to a total dose of 18-32.5 Gy.

RESULTS: HFIR of the tumor bed was easily accomplished facilitating delivery of high radiation doses to the retroperitoneum. No major late effects of treatment have been observed with a follow-up of 15 and 28 months, respectively. Details of the brachytherapy procedure are presented.

CONCLUSION: HFIR via intraoperatively implanted catheters in the retroperitoneum is a technique suitable for application of a local tumor boost dose. Thus, sufficiently high doses of radiation mandatory for long-lasting local tumor control can be delivered in the tumor bed of the retroperitoneum without exceeding normal tissue radiotolerance in this unfavorable disease.