ABSTRACT
INTRODUCTION: The mainstay of soft tissue sarcoma treatment is limb preserving resection, often combined with radiotherapy, preferably preoperative radiotherapy. The goal of this study is to retrospectively assess the effect of preoperative (neoadjuvant) radiotherapy on the minimal distance to critical neurovascular structures, on tumor volume and the necrosis rate. MATERIAL AND METHODS: The data of fifty-one patients treated for a localized soft tissue sarcoma (STS) of the extremity or the trunk were retrospectively reviewed. All patients were analyzed with MR imaging before and after preoperative radiotherapy to determine the impact of radiotherapy on the precise planning and execution of the surgical excision of the tumor. The volume of the tumor as well as the distance to anatomically relevant structures were measured on MRI. Tumor type, characteristics and necrosis rate were obtained from the pathology report. RESULTS: At latest follow-up (median 51 months (range 6-113)) 32/51 (63%) patients were alive. The minimal distance between the myxoid liposarcomas (n = 12) and the vessels was significantly increased by preoperative radiotherapy from 1.09 mm [0-21.1] to 5.23 mm [0-32.70] (P = 0.045). High-grade tumors showed a significant increase in tumor volume after irradiation (p = 0.03) and a significantly greater necrosis rate than low-grade tumors (p < 0.001). CONCLUSION: Preoperative radiotherapy significantly increases the minimal distance from myxoid liposarcomas to the vessel. In the subgroup of STS that demonstratea volume reduction the distance to nerves and vessels increases, but with the low number of cases, this increase is not statistically significant. The effect of preoperative radiotherapy on the tumor volume varies greatly, whereas the subtype of myxoid liposarcoma shows a significant volume reduction in all cases.
