NEOADJUVANT STEREOTACTIC RADIOTHERAPY (SBRT) FOR EXTREMITIES SOFT TISSUE SARCOMA: A PHASE 2 STUDY

Introduction: Soft tissue sarcomas (STS) comprise a highly heterogeneous group of malignancies of mesenchymal origin, for which surgical excision remains the cornerstone of treatment. For patients amenable to approaches with curative intent, radiation therapy (RT) may be considered either pre- or post-operatively, and the optimal sequence remains debatable. Preoperative RT used at the conventional dose of 50Gy in 25 fractions, while associated with similar local control, may potentially result in reduced rates of fibrosis and joint stiffness , at a cost of increased wound complications when compared to adjuvant RT. In this setting, shortening treatment time and offering a higher biologically ablative dose through Stereotactic Body Radiotherapy (SBRT) has emerged as an effective strategy. Yet, this modality has not been adequately investigating for patients with extremity STS. Patients and Methods: This is a phase II study that included patients with extremity STS of any histological type, who are candidates for conservative surgery. SBRT was delivered by linear accelerator (Axesse®, Elekta ®, Stockholm, Sweden) with a total dose of 40Gy in five fractions, given in alternate days. Surgery was performed four to eight weeks after the completion of RT. Primary endpoint was the rate of postoperative wound complications. Secondary endpoints included the assessment of acute and late toxicities, local control, mestastasis-free survival and overall survival. Results: In this interim analysis, 25 patients have been treated according to the protocol (24 completed all the treatment and one awaits the surgical procedure). Five patients (20%) developed grade 3 cutaneous toxicities related to SBRT, all with resolution by the time of surgery. Two patients with borderline indication to conservative surgery were submitted to limb amputation, and two additional patients were excluded from this analysis as a result of vascular complications of the flap. The rate of postoperative wound complications was 23.8%. After a follow up of 12.3 months (3-42.4), one patient (5%) developed a local recurrence and five patients (25%) developed distant metastases; there were no treatment or disease-related deaths. Conclusion: SBRT followed by conservative surgery is feasible and safe in patients with STS of extremities.

Publikationsverlauf

Artikel online veröffentlicht:
23. Oktober 2019