Intraoperative Electron Radiation Therapy Combined with External Beam Radiation Therapy after Gross Total Resection in Extremity Soft Tissue Sarcoma: A European Pooled Analysis

Factors Influencing Long-Term Local Recurrence, Distant Metastasis, and Survival in Patients with Soft Tissue Sarcoma of the Extremities Treated with Radiotherapy

INTRODUCTION

The prognostic factors for extremity soft-tissue sarcomas (ESTSs) treated with multimodal surgery and radiotherapy (RT) remain a subject of debate across diverse and heterogeneous studies.

METHODS

We retrospectively analyzed nonmetastatic ESTS patients treated with RT between 2007 and 2020 in Strasbourg, France. We assessed local control (LC), distant control (DC), overall survival (OS), and complications.

RESULTS

A total of 169 patients diagnosed with localized ESTS were included. The median age was 64 years (range 21-94 years). ESTS primarily occurred proximally (74.6%) and in the lower limbs (71%). Most tumors were grade 2-3 (71.1%), deep-seated (86.4%), and had R0 margins (63.9%). Most patients were treated with helical tomotherapy (79.3%). The median biologically effective dose (BED) prescribed was 75 BEDGy4 (range 45.0-109.9). The median follow-up was 5.5 years. The 5- and 10-year LC, DC, and OS rates were 91.7%, 76.8%, and 83.8% and 84.2%, 74.1%, and 77.6%, respectively. According to the univariate analysis, LC was worse for patients who received less than 75 BEDGy4 (p = 0.015). Deep tumors were associated with worse OS (p < 0.05), and grade 2-3 and undifferentiated pleomorphic sarcoma (UPS) were linked to both shorter DC and shorter OS (p < 0.05). IMRT was associated with longer LC than 3DRT (p = 0.018). Multivariate analysis revealed that patients with liposarcoma had better OS (p < 0.05) and that patients with distant relapse had shorter OS (p < 0.0001).

CONCLUSION

RT associated with surgical resection was well tolerated and was associated with excellent long-term rates of LC, DC, and OS. Compared with 3DRT, IMRT improved local control. Liposarcoma was a favorable prognostic factor for OS. Intermediate- and high-grade tumors and deep tumors were associated with lower DC and OS.

Prognostic Factors in Extremity Soft Tissue Sarcomas Treated with Radiotherapy: Systematic Review of the Literature

Soft tissue sarcomas of the extremities are rare tumors with various prognostic factors. Their management is debatable due to their inconsistent results within the literature and the lack of large prospective studies. The objective of this systematic review is to analyze the available scientific data on prognostic factors concerning the characteristics of the patients, the disease and the treatments performed, as well as their potential complications, on studies with a median follow-up of 5 years at minimum. A search of articles following the "PRISMA method" and using the PubMed search engine was conducted to select the most relevant studies. Twenty-five articles were selected, according to preestablished criteria. This review provides a better understanding of the prognosis and disease outcome of these tumors. Many factors were described comparing the frequency of occurrence according to the studies, which remain heterogeneous between them. Significant factors that could orient patients to radiotherapy were highlighted. These positive prognostic factors provide valuable insight to optimize radiotherapy treatments for patients treated for soft tissue sarcoma of the extremities.

Lack of radiosensitivity predicts poor disease specific survival in myxoid liposarcoma

BACKGROUND

Compared to other sarcomas, myxoid liposarcoma (ML) is known to be radiosensitive, with improved oncologic outcomes. Although these tumors "shrink" following radiotherapy, there is a paucity of data examining the degree of radiosensitivity and oncologic outcome. The purpose of the study was to evaluate pre- and postradiotherapy tumor volume to determine if size reduction impacts outcome.

METHODS

We reviewed 62 patients with ML undergoing surgical resection combined with preoperative radiotherapy, with pre- and postradiotherapy MRI. This included 34 (55%) males, with a mean age of 47 ± 14 years. All tumors were deep to the fascia, and 12 (19%) patients had tumors with a >5% round-cell component.

RESULTS

The mean volume reduction was 54% ± 29%. Compared to patients with >25% volume reduction, patients with reduction ≤25% had worse 10-year disease specific survival (86% vs. 37%, p < 0.01), in addition to an increased risk of metastatic disease (HR 4.63, p < 0.01) and death due to disease (HR 4.52, p < 0.01).

CONCLUSION

Lack of volume reduction is a risk factor for metastatic disease and subsequent death due to disease in patients with extremity ML treated with combined preoperative radiotherapy and surgery. This data could be used to stratify patients for adjuvant therapies and follow-up intervals.

Evaluation of Efficacy of Adjuvant Radiotherapy in Well-Differentiated Liposarcoma Patients with Positive Surgical Margins: A Population-based Study

Background

The use of adjuvant radiotherapy (RT) for well-differentiated liposarcoma (WD-LPS) patients with positive surgical margins is unclear. We aim to compare the overall survival (OS) and cancer-specific survival (CSS) of well-differentiated liposarcoma patients with positive surgical margins in an RT group and non-RT group.

Methods

WD-LPS patients with positive margins from 2000 to 2018 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and divided into two groups: RT group and non-RT group. Kaplan–Meier survival analysis with the log-rank test was performed to evaluate the difference of overall survival (OS) and cancer-specific survival (CSS) between groups. Univariate and multivariate Cox proportional hazard analyses were performed to identify important prognostic factors of OS and CSS. Analyses were adjusted using propensity-score matching.

Results

We identified 2549 patients: 377 (14.79%) with RT and 2172 (85.21%) without RT. The median age was 61 years, and the median follow-up time was 68 months. The log-rank test revealed that there was no significant difference of CSS between RT and non-RT groups (P = 0.81). The 5-year and 10-year CSS were comparable (P = 0.418 and P = 0.987). Additionally, the use of RT was neither an independent prognostic factor for OS nor CSS. Age, sex, tumor site, the use of chemotherapy were independent prognostic factors for OS after propensity score matching, while race and the tumor site were independent prognostic factors for CSS.

Conclusion

Adjuvant RT had no significant improvement on OS and CSS of WD-LPS patients with positive surgical margins.

Long-term experience with intraoperative electron radiation therapy boost in extremity sarcoma

BACKGROUND

In patients with extremity soft tissue sarcoma (eSTS), we describe outcomes of preoperative external beam radiation therapy (EBRT), limb-sparing surgery (LSS), and intraoperative electron radiation therapy (IOERT).

METHODS

One hundred and eighteen patients with eSTS treated between October 17, 2002 and July 28, 2021 were identified. EBRT was delivered preoperatively followed by LSS and IOERT.

RESULTS

The median follow-up was 24.9 months. The presentation was primary in 102 (94%) patients and recurrent in 6 (6%) patients. Tumor location was lower extremity in 82 (76%) patients and upper extremity in 26 (24%) patients. Stage distribution was as follows: 3 (3%) IA, 24 (22%) IB, 31 (29%) II, 24 (22%) IIIA, and 25 (23%) IIIB. Final surgical margins were negative in 96 (89%) patients. The 5-year local control, failure-free survival, and overall survival were 94%, 75%, and 64%, respectively. Univariate analysis identified age >50, lower extremity, and higher grade as significant negative prognostic factors for overall survival. Grade 3 fracture or osteoradionecrosis requiring surgical fixation, neuropathy, and lymphedema occurred in 7 (6%), 1 (1%), and 0 patients, respectively.

CONCLUSIONS

This study represents one of the largest series using preoperative EBRT, LSS, and IOERT for eSTS, with high local control and a low rate of late severe toxicity.

Long-Term Outcome of Centrally Located Hepatocellular Carcinomas Treated by Radical Resection Combined With Intraoperative Electron Radiotherapy (IOERT)

Purpose

To explore the feasibility and safety of centrally located hepatocellular carcinoma (CL-HCC) treated by narrow-margin resection combined with intraoperative electron radiotherapy (IOERT).

Methods and Materials

From November 2009 to November 2016, 37 consecutive patients were treated with IOERT as adjuvant treatment during narrow-margin resection for CL-HCC. Long-term outcomes, adverse events for surgery, and acute and chronic toxicities were analyzed.

Results

The median follow-up was 57.82 months (range, 3.75-111.41 months). A total dose of 15 Gy (range 12 to 17Gy) (prescribed at the 90% isodose) was delivered with a 0.9cm (range 0.8-1.2 cm) median treatment depth targeting the narrow-margin. The 1-year, 3-year and 5-year OS rates were 91.39%, 88.34% and 88.34%, respectively. The 1-year, 3-year and 5-year DFS rates were 80.81%, 68.59% and 54.17%, respectively. In the univariate analysis, none of the treatment characteristics were predictive of overall survival. Fifteen (40.5%) patients suffered from a recurrence event. No patient had marginal recurrence. The 1-year, 3-year and 5-year intrahepatic recurrence rates were 19.75%, 25.92% and 39.58%, respectively. The 1-year, 3-year and 5-year extrahepatic recurrence rates were 2.7%, 5.95% and 9.87%, respectively. There was no 30-day surgical-related death. Three patients had grade 4, and 28 patients had grade 3 alanine aminotransferase (ALT) levels, and seven patients had grade 4, and 30 patients had grade 3 aspartate transaminase (AST) levels. All of them returned to normal within four months. There was no acute radiation-induced liver injury during follow-up. There were no acute or chronic toxicities associated with IOERT.

Conclusion

IOERT for narrow-margin CL-HCC may achieve good long-term survival outcomes, without significantly increasing acute and chronic toxicities. An IOERT dose of 15Gy may be the safest and most feasible. IOERT might be considered as an adjuvant therapy for CL-HCC patients with a narrow-margin.

Radiation Therapy in Adult Soft Tissue Sarcoma-Current Knowledge and Future Directions: A Review and Expert Opinion

Simple Summary

Radiation therapy (RT) is an integral part of the treatment of adult soft-tissue sarcomas (STS). Although mainly used as perioperative therapy to increase local control in resectable STS with high risk features, it also plays an increasing role in the treatment of non-resectable primary tumors, oligometastatic situations, or for palliation. This review summarizes the current evidence for RT in adult STS including typical indications, outcomes, side effects, dose and fractionation regimens, and target volume definitions based on tumor localization and risk factors. It covers the different overall treatment approaches including RT either as part of a multimodal treatment strategy or as a sole treatment and is accompanied by a summary on ongoing clinical research pointing at future directions of RT in STS.

Abstract

Radiation therapy (RT) is an integral part of the treatment of adult soft-tissue sarcomas (STS). Although mainly used as perioperative therapy to increase local control in resectable STS with high risk features, it also plays an increasing role in the treatment of non-resectable primary tumors, oligometastatic situations, or for palliation. Modern radiation techniques, like intensity-modulated, image-guided, or stereotactic body RT, as well as special applications like intraoperative RT, brachytherapy, or particle therapy, have widened the therapeutic window allowing either dose escalation with improved efficacy or reduction of side effects with improved functional outcome. This review summarizes the current evidence for RT in adult STS including typical indications, outcomes, side effects, dose and fractionation regimens, and target volume definitions based on tumor localization and risk factors. It covers the different overall treatment approaches including RT either as part of a multimodal treatment strategy or as a sole treatment, namely its use as an adjunct to surgery in resectable STS (perioperative RT), as a primary treatment in non-resectable tumors (definitive RT), as a local treatment modality in oligometastatic disease or as palliative therapy. Due to the known differences in clinical course, general treatment options and, consequently, outcome depending on lesion localization, the main part of perioperative RT is divided into three sections according to body site (extremity/trunk wall, retroperitoneal, and head and neck STS) including the discussion of special applications of radiation techniques specifically amenable to this region. The review of the current evidence is accompanied by a summary on ongoing clinical research pointing at future directions of RT in STS.

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

Background

Soft 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.

Methods

Thirty-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.

Results

Median 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.

Conclusion

Electronic 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.

Extremity Soft Tissue Sarcoma: Role of Local Control

OPINION STATEMENT

For localized extremity soft tissue sarcoma (eSTS), treatment is individualized and each patient needs to be evaluated by a multidisciplinary team at a referral sarcoma center specialized in the care of sarcoma. For a majority of patients, treatment for eSTS involves limb-salvage surgery, with or without the addition of radiation therapy. Surgery should only be performed by surgeons specifically fellowship trained in the resection of eSTS. Surgery alone may be considered for small, low-grade, and superficial tumors as long a wide (≥ 2 cm) margin can be achieved. In cases where a less than wide negative margin can be achieved, radiation therapy should be utilized to facilitate a planned close margin resection to preserve critical structures (such as nerves, blood vessels, and bone) without a significant impact on oncologic outcomes. Soft tissue sarcomas are rare, and as such patients often present following an inadvertent excision. In these situations, we recommend preoperative radiation and wide tumor bed re-excision, as rates of residual tumor can be high in this scenario. While there is large amount of evidence to support the use of radiotherapy to enhance local tumor control, the evidence to support the use of chemotherapy to enhance local tumor control is lacking, and as such cannot be recommended for all patients.

Electron radiotherapy (IOERT) for applications outside of the breast: Dosimetry and influence of tissue inhomogeneities

PURPOSE

The purpose of study is to investigate the dosimetry of electron intraoperative radiotherapy (IOERT) of the Intraop Mobetron 2000 mobile LINAC in treatments outside of the breast. After commissioning and external validation of dosimetry, we report in vivo results of measurements for treatments outside the breast in a large patient cohort, and investigate if the presence of inhomogeneities can affect in vivo measurements.

METHODS AND MATERIALS

Applicator factors and profile curves were measured with a stereotactic diode. The applicators factors of the 6 cm flat and beveled applicators were also confirmed with radiochromic films, parallel-plate ion chamber and by an external audit performed with ThermoLuminescent Dosimeters (TLDs). The influence of bone on dose was investigated by using radiochromic films attached to an insert equivalent to cortical bone, immersed in the water phantom. In vivo dosimetry was performed on 126 patients treated with IOERT using metal oxide-silicon semiconductor field effect transistors (MOSFETs) placed on the tumor bed.

RESULTS

Relatively small differences were found among different detectors for measurements of applicator factors. In the external audit, the agreement with the TLD was mostly within ±0.2%. The largest increase of dose due to the presence of cortical bone insert was +6.0% with energy 12 MeV and 3 cm applicator. On average, in vivo dose was significantly (+3.1%) larger than prescribed dose.

CONCLUSION

IOERT in applications outside the breast results in low discrepancies between in vivo and prescribed doses, which can be also explained with the presence of tissue inhomogeneity.