Role of post-operative radiation boost for soft tissue sarcomas with positive margins following pre-operative radiation and surgery

UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

Incidence and Risk Factors for Extremity Osteoradionecrosis after Limb-Sparing Surgery and Adjuvant Radiotherapy

Osteoradionecrosis (ORN) is a major complication after radiotherapy. Most studies on ORN have focused on patients with mandibular lesions, with few studies including patients with extremity soft tissue sarcoma (STS). We included 198 patients with extremity STS who underwent limb-sparing surgery and adjuvant radiotherapy between 2004 and 2017. The incidence rate of extremity ORN was 3.5% (7/198), with most lesions (6/7) located in the lower extremities. The mean follow-up time was 62 months. Clinical presentations included chronic ulcers, soft tissue necrosis, sinus discharge, bone nonunion, and pathological fractures. Compared with the non-ORN group, the ORN group had a significantly higher total radiation dose (68 Gy vs. 64 Gy, p = 0.048) and greater use of intraoperative periosteal stripping (p = 0.008). Repeat surgeries and subsequent soft tissue reconstruction or limb amputation were performed as treatments. The risk and management of ORN in patients with extremity STS was ignored previously. Because the disease is complex and affects both clinicians and patients, careful surveillance should be undertaken.

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.

Radiation Therapy for Soft Tissue Sarcoma

Radiation therapy is an integral component of local management with oncologic resection for soft tissue sarcoma. Radiotherapy is indicated in patients at an increased risk of local recurrence so that improved local control may be achieved. Sequencing of radiotherapy and resection should be determined by multidisciplinary input before treatment initiation. For most patients, preoperative delivery of radiation therapy is preferred. In patients initially thought to be at low risk for local recurrence and found to have unexpected adverse pathologic features at resection, postoperative radiation therapy is indicated. The use of radiation therapy for retroperitoneal sarcoma is controversial; when used, preoperative delivery of radiation is recommended.

Preoperative Radiation for Soft Tissue Sarcomas: How Much Is Needed?

OPINION STATEMENT

Preoperative radiation therapy is an important component of curative treatment for extremity and superficial trunk soft tissue sarcomas. It has traditionally been delivered to a dose of 50 Gy in 2 Gy fractions over 5 weeks. With significant advances in the multidisciplinary approach to soft tissue sarcomas, preoperative radiation therapy may be omitted for certain cases, delivered over a shortened period of time (1-3 weeks), deintensified for myxoid liposarcomas, or combined with systemic therapy to improve the therapeutic ratio. This article reviews the innovative preoperative radiation therapy strategies currently used to treat extremity and superficial trunk soft tissue sarcomas.

[Preoperative versus postoperative radiotherapy in soft tissue sarcomas: State of the art and perspectives]

Radiation therapy is a standard treatment for limbs soft tissue sarcomas. Preoperative versus postoperative radiotherapy has been a controversial topic for years. With preoperative irradiation, the treatment volume is more limited, the delivered dose possibly lower and the tumor volume easier to delimit. Only one randomized trial compared these two irradiation sequences. The results in terms of local control and survival were equivalent but the risk of acute postoperative complications was higher if irradiation was administered before surgery. However, in the latest update of this trial, patients who received adjuvant irradiation exhibited more severe late toxicity than those treated preoperatively. In addition, with modern irradiation techniques such as conformal with image-guided intensity modulated radiotherapy and flap coverage techniques, the incidence of complications after preoperative irradiation were lower than historically published rates. Locally advanced proximal sarcomas and the failure of other neoadjuvant treatments are nowadays classical indications for preoperative irradiation. As with other neoadjuvant treatments, induction radiotherapy must be personalized according to the histological subtype, the tumor site and the benefit/risk ratio, which is best appreciated by a multidisciplinary surgical and oncological team in a specialized center in the management of soft-tissue sarcomas.

Temporizing Wound VAC Dressing Until Final Negative Margins are Achieved Reduces Myxofibrosarcoma Local Recurrence

BACKGROUND

The microinvasive nature of suprafascial myxofibrosarcoma reduces the accuracy of intraoperative margin assessment, and tumor bed resections after soft-tissue reconstruction are unreliable. In 2017, we began temporizing the excised tumor bed with a wound VAC, delaying soft-tissue coverage until final negative margins were achieved. We compare the oncologic/surgical outcomes of suprafascial myxofibrosarcomas managed with VAC temporization (VT) with single-stage excision/reconstruction (SS).

METHODS

We retrospectively studied suprafascial myxofibrosarcomas managed from January 1, 2000 to January 1, 2019 for patients who received neoadjuvant or adjuvant radiation and had at least 2 years of oncologic follow-up at a tertiary referral cancer center. Our primary outcome was local recurrence. Comparisons were performed by using Fisher's exact test or Student's t test. A p value < 0.05 was considered significant.

RESULTS

Fifty-three patients (18 VAC temporized, 35 single stage) were included. While VT patients were older (74.9 ± 10.2 vs. 63.9 ± 13.6, p = 0.003), treatment groups did not significantly differ with respect to comorbidity, tumor volume, stage and grade. VT patients had significantly fewer local recurrences (5.6% vs. 28.6% after SS, p = 0.048) and R1 resections that required an unplanned readmission for tumor bed reexcision (0% vs. 37.1% after SS, p = 0.002). VT required more total surgeries (2.8 ± 0.9 vs. 1.8 ± 0.9 for SS, p = 0.0002). Postoperative infectious and wound complications were equivalent.

CONCLUSIONS

Our VAC temporization strategy had a significantly lower LR than SS treatment. While high quality multi-institutional validation is required, VT may represent a paradigm shift in the management of myxofibrosarcoma.

Neoadjuvant Radiotherapy-Related Wound Morbidity in Soft Tissue Sarcoma: Perspectives for Radioprotective Agents

Historically, patients with localized soft tissue sarcomas (STS) of the extremities would undergo limb amputation. It was subsequently determined that the addition of radiation therapy (RT) delivered prior to (neoadjuvant) or after (adjuvant) a limb-sparing surgical resection yielded equivalent survival outcomes to amputation in appropriate patients. Generally, neoadjuvant radiation offers decreased volume and dose of high-intensity radiation to normal tissue and increased chance of achieving negative surgical margins-but also increases wound healing complications when compared to adjuvant radiotherapy. This review elaborates on the current neoadjuvant/adjuvant RT approaches, wound healing complications in STS, and the potential application of novel radioprotective agents to minimize radiation-induced normal tissue toxicity.

Neoadjuvant Treatment Options in Soft Tissue Sarcomas

Due to the heterogeneity of soft tissue sarcomas (STS), the choice of the proper perioperative treatment regimen is challenging. Neoadjuvant therapy has attracted increasing attention due to several advantages, particularly in patients with locally advanced disease. The number of available neoadjuvant modalities is growing continuously. We may consider radiotherapy, chemotherapy, targeted therapy, radiosensitizers, hyperthermia, and their combinations. This review discusses possible neoadjuvant treatment options in STS with an emphasis on available evidence, indications for each treatment type, and related risks. Finally, we summarize current recommendations of the STS neoadjuvant therapy response assessment.

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.

Brazilian consensus on the diagnosis and treatment of extremities soft tissue sarcomas

INTRODUCTION

Soft tissue sarcomas (STSs) are rare tumors and constitute only 1% of all tumors in adults. Indeed, due to their rarity, most cases in Brazil are not treated according to primary international guidelines.

METHODS

This consensus addresses the treatment of STSs in the extremities. It was made by workgroups from Brazilian Societies of Surgical Oncology, Orthopaedics, Clinical Oncology, Pathology, Radiology and Diagnostic Imaging, and Radiation Oncology. The workgroups based their arguments on the best level of evidence in the literature and recommendations were made according to diagnosis, staging, and treatment of STSs. A meeting was held with all the invited experts and the topics were presented individually with the definition of the degree of recommendation, based on the levels of evidence in the literature.

RESULTS

Risk factors and epidemiology were described as well as the pathological aspects and imaging. All recommendations are described with the degree of recommendation and levels of evidence.

CONCLUSION

Recommendations based on the best literature regional aspects were made to guide professionals who treat STS. Separate consensus on specific treatments for retroperitoneal, visceral, trunk, head and neck sarcomas, and gastrointestinal stromal tumor, are not contemplated into this consensus.

Patterns of Practice Survey: Radiotherapy for Soft Tissue Sarcoma of the Extremities

Background Neoadjuvant or adjuvant radiotherapy (RT) for extremity soft tissue sarcoma (STS) confers significant local control benefit. To determine patterns of practice, a survey of RT planning practices was undertaken. Method Members of the Connective Tissue Oncology Society and Canadian Association of Radiation Oncology participated in this survey pertaining to general practice patterns of RT for extremity STS, patterns of contouring and planning, and use of quality control measures such as guidelines, tumor boards, and quality assurance rounds. Results A total of 58 radiation oncologists treating extremity STS from 12 countries responded. 89.7% work in academically affiliated centres, and 55.2% saw at least 20 cases of extremity STS per year. Most (96.7%) had access to multidisciplinary sarcoma boards (85.5% of those discussed every referred sarcoma case). 78.6% held quality assurance rounds. Most (92.9%) used planning guidelines. Pre-operative RT was used nearly twice as much as post-operative RT. CT simulation with MR fusion was used by 94.6%. Patterns of clinical target volume (CTV) contouring for both superficial and deep STS were variable. 69.8% contoured a normal soft tissue strip for extremity sarcoma, 13.5% without routine constraints and the remainder with various constraints. Most (91.1%) used 50 Gy in 25 fractions pre-operatively and 39.6% reported using post-operative RT boost for positive margins. Post-operative dose was more variable from 59.4 Gy to 70 Gy. Conclusion Major aspects of RT planning for extremity STS were similar among the responders, and most were academically affiliated. Over twice as many employed pre-operative as opposed to post-operative RT. There was considerable heterogeneity in use of: margins for contouring, normal soft tissue strip as an avoidance structure, and boost for positive margins. This survey shows variable patterns of practice and identifies areas that may require further research.

Does an Algorithmic Approach to Using Brachytherapy and External Beam Radiation Result in Good Function, Local Control Rates, and Low Morbidity in Patients With Extremity Soft Tissue Sarcoma?

BACKGROUND

High-dose-rate brachytherapy (HDR-BT) and external-beam radiation therapy (EBRT) are two modalities used in the treatment of soft tissue sarcoma. Previous work at our institution showed early complications and outcomes for patients treated with HDR-BT, EBRT, or a combination of both radiation therapy modalities. As the general indications for each of these approaches to radiation therapy differ, it is important to evaluate the use of each in an algorithmic way, reflecting how they are used in contemporary practice at sites that use these treatments. QUESTION/PURPOSES: (1) To determine the proportions of intermediate- and long-term complications associated with the use of brachytherapy in the treatment of primary high-grade extremity soft tissue sarcomas; (2), to characterize the long-term morbidity of the three radiation treatment groups using the Radiation Therapy Oncology Group/ European Organization for Research and Treatment of Cancer (RTOG/EORTC) Late Radiation Morbidity Scoring Scheme; (3) to determine whether treatment with HDR-BT, EBRT, and HDR-BT+EBRT therapy, in combination with limb-salvage surgery, results in acceptable local control in this high-risk group of sarcomas.

METHODS

We retrospectively studied data from 171 patients with a diagnosis of high-grade extremity soft tissue sarcoma treated with limb-sparing surgery and radiation therapy between 1990 and 2012 at our institution, with a mean followup of 72 months. Of the 171 patients, 33 (20%) were treated with HDR-BT, 128 (75%) with EBRT, and 10 (6%) with HDR-BT+EBRT. We excluded 265 patients with soft tissue sarcomas owing to axial tumor location, previous radiation to the affected extremity, incomplete patient records, patients receiving primary amputation, recurrent tumors, pediatric patients, low- and intermediate-grade tumors, and rhabdoid histology. Fifteen patients (9%) were lost to followup for any reason including died of disease or other causes during the first 12 months postoperatively. This included four patients who received HDR-BT (12%), 11 who received EBRT (9%), and none who received HDR-BT+EBRT (0%) with less than 12 months followup. Determination of radiation therapy technique for each patient was individualized in a multidisciplinary forum of sarcoma specialists. Anticipated close or positive surgical margins and a low likelihood of complex soft tissue procedures were factors that encouraged use of brachytherapy, whereas the anticipated need for secondary procedures and/or soft tissue coverage encouraged use of EBRT alone. Combination therapy was used when the treatment volume exceeded the treatment field of the brachytherapy catheters or when the catheters were used to boost a close or positive surgical margin. Local recurrence, complications, and morbidity outcomes scores (RTOG) were calculated based on chart review. Between-group comparisons pertaining to the proportion of patients experiencing complications, morbidity outcomes scores, and local recurrence rates were not performed because of dissimilarities among the patients in each group at baseline.

RESULTS

The HDR-BT treatment group showed a high incidence of intermediate-term complications, with the three most common being: deep infection (33%, 11 of 33); dehiscence and delayed wound healing (24%, eight of 33); and seroma and hematoma (21%, seven of 33). The EBRT group showed a high incidence of intermediate- and long-term complications with the three most common being: chronic radiation dermatitis (35%, 45 of 128); fibrosis (27%, 35 of 128); and chronic pain and neuritis (13%, 16 of 128). The RTOG scores for each treatment group were: HDR-BT 0.8 ± SD 1.2; EBRT 1.9 ± 2.0; and HDR-BT+EBRT 1.7 ± 1.7. Overall, 142 of 169 (84%) patients were free from local recurrence: 27 (82%) in the HDR-BT group, 108 (86%) in the EBRT group, and seven (70%) in the combination therapy group.

CONCLUSIONS

In this single-institution study, an algorithmic approach to using HDR-BT and EBRT in the treatment of patients with high-grade soft tissue sarcomas can yield acceptable complication rates, good morbidity outcome scores, and a high degree of local control. Based on these results, we believe HDR-BT is best for patients with an anticipated close margin, a positive surgical margin, and for patients who are unlikely to receive a complex soft tissue procedure. Conversely, if a secondary procedure and/or soft tissue coverage are likely to be used, EBRT alone may be reasonable. Finally, combination therapy might be considered when the treatment volume exceeded the treatment field capacity for HDR-BT or when the catheters were used to boost a close or positive surgical margin.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Perioperative Management of Extremity Soft Tissue Sarcomas

Surgery is potentially curative for primary nonmetastatic extremity soft tissue sarcomas. After surgery alone, patients may remain at risk for local recurrences and/or metastatic disease. To reduce the likelihood of a local relapse, the addition of radiotherapy (RT) to limb-sparing surgery may result in higher local control rates of at least 85%. Generally, it can be stated that local control after both preoperative and postoperative RT is comparable, but that preoperative RT comes with a more favorable toxicity profile after prolonged follow-up, albeit at the cost of a higher wound complication rate. Furthermore, recent data suggest that preoperative RT is more cost effective. To reduce the risk of subsequent metastatic disease, systemic chemotherapy can be introduced early during the primary management of these patients. These systemic chemotherapy regimens can also be applied both preoperatively and postoperatively. Finally, with the aim of increasing the antitumor response of perioperative RT, these agents may even be combined with RT, concurrently and sequentially. While designing new preoperative combination regimens, responses should be carefully monitored by both sophisticated radiologic and pathologic evaluations. This article reviews all these aspects, in addition to limb-sparing surgery.

Intraoperative radiotherapy for extremity soft-tissue sarcomas: can long-term local control be achieved?

BACKGROUND

Intraoperative electron-beam radiation therapy (IOERT) during limb-sparing surgery has the advantage of delivering a single high boost dose to sarcoma residues and surgical bed area near to radiosensitive structures with limited toxicity. Retrospective studies have suggested that IOERT may improve local control compared to standard radiotherapy and we aimed to demonstrate this theory. Therefore, we performed an observational prospective study to determine (1) if it is possible to achieve high local control by adding IOERT to external-beam radiation therapy (EBRT) in extremity soft-tissue sarcomas (STS), (2) if it is possible to improve long-term survival rates, and (3) if toxicity could be reduced with IOERT MATERIALS AND METHODS: From 1995-2003, 39 patients with extremity STS were treated with IOERT and postoperative radiotherapy. The median follow-up time was 13.2 years (0.7-19). Complications, locoregional control and survival rates were collected.

RESULTS

Actuarial local control was attained in 32 of 39 patients (82%). Control was achieved in 88% of patients with primary disease and in 50% of those with recurrent tumors (p = 0.01). Local control was shown in 93% of patients with negative margins and in 50% of those with positive margins (p = 0.002). Limb-sparing was achieved in 32 patients (82%). The overall survival rate was 64%. 13% of patients had grade ≥3 acute toxicity, and 12% developed grade ≥3 chronic toxicity.

CONCLUSION

IOERT used as a boost to EBRT provides high local control and limb-sparing rates in patients with STS of the extremities, with less toxicity than EBRT alone.

High-grade myxofibrosarcoma of the abdominal wall

The authors present a case of a 57-year-old man, who presented to the surgical clinic with a mass in the suprapubic region. A CT scan revealed a well-circumscribed lobular, heterogeneous soft tissue mass measuring 12×8.6×7.8 cm. The final histopathological diagnosis from the resection of the lesion was a myxofibrosarcoma (MFS), grade 3. The management of MFS includes surgical and oncological options which are reviewed here. These are aimed at complete excision and reducing the risk of local occurrence.

Neoadjuvant chemotherapy in soft tissue sarcomas: latest evidence and clinical implications

Soft tissue sarcomas are a rare and multifaceted group of solid tumours. Neoadjuvant chemotherapy is increasingly used to limit loss of function after wide surgical excision with the ultimate aim of improving patient survival. Recently, advances in the identification of effective treatment strategies and improvements in patient risk stratification have been reached. A randomized trial demonstrated that neoadjuvant epirubicin and ifosfamide improves survival of patients affected by five high-risk soft tissue sarcoma histologies of trunk and extremities, including undifferentiated pleomorphic sarcoma, myxoid liposarcoma, synovial sarcoma, malignant peripheral nerve sheath tumours, and leiomyosarcoma. Selection of patients for these treatments is expected to be improved by the eighth edition of the American Joint Committee on Cancer (AJCC) TNM staging system, as it tailors T-stage categories on primary tumour site and considers a prognostic nomogram for retroperitoneal sarcoma, which also includes soft tissue sarcoma histology and other patient and tumour features not directly included in the TNM staging. Within this framework, this article will present neoadjuvant treatment strategies for high-risk soft tissue sarcoma, emphasizing the most recent advances and discussing the need for further research to improve the effectiveness of neoadjuvant treatments.

Management of soft-tissue sarcomas; treatment strategies, staging, and outcomes

Soft-tissue sarcomas (STS) are a rare group of malignant tumors which can affect any age group. For the majority of patients who present with a localized STS, treatment involves a multidisciplinary team decision-making approach ultimately relying on surgical resection with or without adjuvant radiation for successful limb salvage. The goals of treatment are to provide the patient with a functional extremity without local tumor relapse. The purpose of this article is to review the treatment of extremity STS, with a focus on staging, treatment options, and outcomes.

Radiation Therapy for Soft-Tissue Sarcomas: A Primer for Radiologists

Radiation therapy (RT) plays an important role in multimodality therapy for soft-tissue sarcomas (STS). RT treatment paradigms have evolved significantly in recent years, and many different complex RT modalities are commonly used in STS. These include external-beam RT, intensity-modulated RT, stereotactic body RT, and brachytherapy. Imaging is essential throughout the treatment process. Plain radiographs, computed tomography (CT), magnetic resonance imaging, ultrasonography, and positron emission tomography/CT all play potential roles in the management of STS. Before RT, high-quality imaging is needed to direct management decisions, both by global tumor staging and detailed assessment of the extent of local disease. At the time of RT, precise planning imaging is required to delineate tumor volumes, including gross tumor volume, clinical target volume, and planning target volume, which are used to direct therapy. In addition, imaging at the time of RT must outline the location of adjacent vital organs, to optimize treatment efficacy and minimize toxicity. After RT, imaging is needed to assess the patient for tumor response to therapy. In addition, imaging at regular intervals is often required to monitor for recurrence of disease and potential complications of therapy. The purpose of this review is to familiarize radiologists with the indications for RT in STS, common therapeutic modalities used, roles of imaging throughout the treatment process, and complications of therapy.

The role of radiotherapy in the management of localized soft tissue sarcomas

The combination of radiotherapy (RT) and function-preserving surgery is the most usual contemporary approach in the management of soft tissue sarcomas (STS). Pre- and postoperative RT result in similar local control rates, as shown by a landmark trial in extremity STS. In this review, the role of RT in the management of extremity STS will be discussed, but STS in other sites, including retroperitoneal STS, will also be addressed. The focus will consider various aspects of RT including strategies to reduce the volume of tissue being irradiated, dose, scheduling, and the possible of omission of RT in selected cases. Finally, technology advances through the use of intensity-modulated radiotherapy (IMRT), image-guided IMRT, intraoperative radiotherapy (IORT) and particle therapy will also be discussed.

Preoperative radiotherapy for extremity soft tissue sarcoma; past, present and future perspectives on dose fractionation regimens and combined modality strategies

INTRODUCTION

This critical review aims to summarize published data on limb sparing surgery for extremity soft tissue sarcoma in combination with pre-operative radiotherapy (RT).

METHODS

This review is based on peer-reviewed publications using a PubMed search on the MeSH headings "soft tissue sarcoma" AND "preoperative radiotherapy". Titles and abstracts screened for data including "fraction size AND/OR total dose AND/OR overall treatment time", "chemotherapy", "targeted agents AND/OR tyrosine kinase inhibitors", are collated. Reference lists from some articles have been studied to obtain other pertinent articles. Additional abstracts presented at international sarcoma meetings have been included as well as information on relevant clinical trials available at the ClinicalTrials.gov website.

RESULTS

Data are presented for the conventional regimen of 50-50.4Gy in 25-28 fractions in 5-6 of weeks preoperative external beam RT with respect to the regimen's local control probability compared to surgery alone, as well as acute and late toxicities. The rationale and outcome data for hypofractionated and/or reduced dose regimens are discussed. Finally, combination schedules with conventional chemotherapy and/or targeted agents are summarized.

CONCLUSION

Outside the setting of well-designed prospective clinical trials, the conventional 50Gy in 5-6week schedule should be considered as standard. However, current and future studies addressing alternative fraction size, total dose, overall treatment time and/or combination with chemotherapy or targeted agents may reveal regimens of equal or increased efficacy with reduced late morbidities.

Evaluation of LiF:Mg,Ti (TLD-100) for Intraoperative Electron Radiation Therapy Quality Assurance

BACKGROUND

Purpose of the present work was to investigate thermoluminescent dosimeters (TLDs) response to intraoperative electron radiation therapy (IOERT) beams. In an IOERT treatment, a large single radiation dose is delivered with a high dose-per-pulse electron beam (2-12 cGy/pulse) during surgery. To verify and to record the delivered dose, in vivo dosimetry is a mandatory procedure for quality assurance. The TLDs feature many advantages such as a small detector size and close tissue equivalence that make them attractive for IOERT as in vivo dosimeters.

METHODS

LiF:Mg,Ti dosimeters (TLD-100) were irradiated with different IOERT electron beam energies (5, 7 and 9 MeV) and with a 6 MV conventional photon beam. For each energy, the TLDs were irradiated in the dose range of 0-10 Gy in step of 2 Gy. Regression analysis was performed to establish the response variation of thermoluminescent signals with dose and energy.

RESULTS

The TLD-100 dose-response curves were obtained. In the dose range of 0-10 Gy, the calibration curve was confirmed to be linear for the conventional photon beam. In the same dose region, the quadratic model performs better than the linear model when high dose-per-pulse electron beams were used (F test; p<0.05).

CONCLUSIONS

This study demonstrates that the TLD dose response, for doses ≤10 Gy, has a parabolic behavior in high dose-per-pulse electron beams. TLD-100 can be useful detectors for IOERT patient dosimetry if a proper calibration is provided.

Soft tissue masses for the general orthopedic surgeon

Soft tissue sarcomas are a rare, heterogeneous group of malignancies that should be included in the differential diagnosis for any patient presenting with a soft tissue mass. This article reviews strategies for differentiating between benign and malignant soft tissue masses. Epidemiology, appropriate workup, and treatment of soft tissue sarcomas are reviewed.

Adjuvant radiation for soft tissue sarcomas

Over recent decades, limb-preservation surgery in combination with radiotherapy achieves local control rates exceeding 90% for extremity soft tissue sarcoma (STS). Local control is not as successful for retroperitoneal sarcoma (approximately 60%) despite aggressive surgical approaches including en bloc resection of uninvolved adjacent organs combined with intensity modulated radiotherapy (IMRT). This review will discuss the indications for adjuvant radiation therapy (RT) for primary presentation of soft tissue sarcoma: "What," referring to the type and manner of planning and delivery of RT; "When," referring to the timing and scheduling of RT; and "Why," referring to the rationale for the use of RT will be addressed. From a practical stand point, this Educational Chapter on "adjuvant RT" will focus on pre- and postoperative RT in the context of gross total resection for extremity and retroperitoneal soft tissue sarcoma, the two most frequent paradigms for the use of adjuvant RT.