Intraoperative radiotherapy with low energy x-rays for primary and recurrent soft-tissue sarcomas

Elena Sperk,Gustavo R Sarria,Frederik Wenz,Vera Petrova,Yasser Abo-Madyan,Frank A Giordano

doi:10.1186/s13014-020-01559-7

Abstract

BackgroundSoft tissue sarcomas (STS) treatment remains a therapeutic challenge. Intraoperative radiotherapy (IORT) resembles a safe and efficient for STS treatment. The first data on electronic-IORT (eIORT) using low-energy photons is herein presented.MethodsThirty-one patients with newly and recurrent STS were retrospectively assessed. EIORT was applied with low-energy photons during surgery. The dose was either prescribed to the applicator surface (spherical applicators) or 5 mm depth (flat applicators). Overall progression-free survival (O-PFS), local progression-free survival (L-PFS), overall survival (OS) and adverse events were evaluated.ResultsMedian follow-up was 4.88 (1.0–8.95) years. Twenty-five patients (80.6%) had recurrent STS with prior treatment. The resection status was R1 in 25.8% and R2 in 6.5%. The distribution was 51.7% for extremities, 35.5% for abdomen and pelvis, 9.7% for thorax and 3.2% for head and neck tumors. The median O-PFS was 11.0 months, with 42.6% 5-year estimated O-PFS. The only local recurrence in the primary setting occurred after 22 months. Median L-PFS in recurrent STS was 12.5 months, with 65.5% 5-year estimated L-PFS. The 5-year OS estimated rate was 94.7% (3 events after 7 years). No G3 toxicity related to eIORT was observed. Two patients exhibited G2 acute neuropathic pain. Late neuropathic pain was seen in 6 patients being 3 graded as G1 and 3 as G2. No wound-related toxicity was found.ConclusionElectronic IORT with low-energy photons is a safe treatment option for STS, yielding similar outcomes as historical series reporting IORT with electrons or HDR brachytherapy.

Highlights

With an approximate overall incidence of 6/100000 [1] and less than 1% of the all-cancers global prevalence, sarcoma is a rare tumor entity [2]
The cornerstone for sarcoma management remains to be the upfront surgical approach and the addition of radiotherapy in cases where needed [8, 9], according to a variety of features listed in different international guidelines [10], which enhances the therapeutic ratio compared to a single-intervention approach, as randomized trials have previously reported with an overall local control rate increase of 20–25% [11, 12]
Risk structures and previous External-beam radiotherapy (EBRT) irradiation, electronic Intraoperative radiotherapy (IORT) was delivered with doses between 5 and 20 Gy prescribed to 5 mm or at the applicator surface

Summary

Introduction

With an approximate overall incidence of 6/100000 [1] and less than 1% of the all-cancers global prevalence, sarcoma is a rare tumor entity [2]. It accounts for 13.040 new patients per year in the US [3] and the overall lethality of this tumor is still high [4]. Historical data shows that approximately 50% of patients with primary retroperitoneal tumors do not achieve a complete resection due to anatomic challenges and even in case tumors were completely resected, patients still exhibit a 50% risk for recurrence [13]. The first data on electronic-IORT (eIORT) using low-energy photons is presented

Methods

Results

Discussion

Conclusion