Results of radiation therapy for unresected soft-tissue sarcomas

Effect of palliative radiation dose on symptom response in metastatic sarcomas

Purpose

Palliative radiotherapy (RT) plays a crucial role in alleviating symptoms associated with metastatic sarcoma. However, there is a lack of consensus on the optimal palliative radiation dose and fractionation for metastatic sarcomas. We analyzed the association between biologically effective radiation dose and symptom response for patients who underwent palliative RT for metastatic sarcomas.

Methods and materials

We retrospectively identified patients with metastatic sarcoma treated with palliative RT between 1999 and 2021 at our institution. We assessed the association between equivalent dose in 2 Gy fractions (EQD2) with an α/β of three and symptom relief or overall survival (OS) using univariable and multivariable analyses.

Results

Of the 198 metastatic sites treated, the most common indications for palliative radiation were pain (n = 181, 91 %) and compression of adjacent structures (n = 16, 8 %). In our analysis, an EQD2 of > 20 Gy was associated with greater rates of short-term symptom relief (n = 143, 85 %) at the RT site compared to an EQD2 of ≤ 20 Gy (n = 14, 54 %, P = 0.001) with no reports of grade 3 or higher toxicity. However, there was no significant improvement in short-term symptom relief for higher radiation doses. Patients treated with an EQD2 of ≤ 20 Gy had a significantly worse performance status, but there was no significant difference in overall survival based on EQD2 on multivariable analysis.

Conclusions

An EQD2 ≤ 20 Gy (e.g., 8 Gy in 1 fraction) provided inadequate palliative benefit in this series. An EQD2 > 20 Gy resulted in greater rates of symptom palliation in metastatic sarcomas, but further dose escalation did not improve symptom response or durability. These findings suggest standard palliative regimens such as 20 Gy in 5 fractions (EQD2 of 28 Gy) are effective for patients with metastatic sarcomas.

ACR-ARS Practice Parameter for the Performance of Proton Beam Therapy

Purpose

This practice parameter for the performance of proton beam radiation therapy was revised collaboratively by the American College of Radiology (ACR) and the American Radium Society (ARS). This practice parameter was developed to serve as a tool in the appropriate application of proton therapy in the care of cancer patients or other patients with conditions in which radiation therapy is indicated. It addresses clinical implementation of proton radiation therapy, including personnel qualifications, quality assurance (QA) standards, indications, and suggested documentation.

Materials and Methods

This practice parameter for the performance of proton beam radiation therapy was developed according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters - Radiation Oncology of the ACR Commission on Radiation Oncology in collaboration with the ARS.

Results

The qualifications and responsibilities of personnel, such as the proton center Chief Medical Officer or Medical Director, Radiation Oncologist, Radiation Physicist, Dosimetrist and Therapist, are outlined, including the necessity for continuing medical education. Proton therapy standard clinical indications and methodologies of treatment management are outlined by disease site and treatment group (e.g. pediatrics) including documentation and the process of proton therapy workflow and equipment specifications. Additionally, this proton therapy practice parameter updates policies and procedures related to a quality assurance and performance improvement program (QAPI), patient education, infection control, and safety.

Conclusion

As proton therapy becomes more accessible to cancer patients, policies and procedures as outlined in this practice parameter will help ensure quality and safety programs are effectively implemented to optimize clinical care.

Radiation therapy improves survival in elderly patients with localized extremity soft tissue sarcoma

BACKGROUND

This study aims to evaluate the efficacy of radiation therapy in enhancing survival outcomes among elderly patients diagnosed with localized extremity soft tissue sarcomas (STSs). Furthermore, it seeks to explore whether the survival benefits conferred by radiation therapy differ according to tumor characteristics and treatment modalities.

METHODS

We conducted a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database to identify patients aged 80 years and older diagnosed with localized extremity STSs. The study assessed 1498 eligible patients, analyzing cancer-specific survival (CSS) and overall survival (OS) through Kaplan-Meier survival analysis and Cox proportional hazards modeling. Propensity score matching was employed to adjust for potential confounders.

RESULTS

Among the analyzed patients, 773 patients underwent radiation therapy (Radiation group), while 725 patients either did not receive radiation therapy or it was unknown if they had (No-Radiation group). The 5-year OS rate was 40% in the radiation group compared to 38% in the no-radiation group. After propensity score matching, radiation therapy was associated with a significant improvement in OS (P = 0.005, HR = 0.8, 95% CI 0.7-0.9). Subgroup analyses indicated that patients undergoing primary tumor resection benefited most from radiation therapy in terms of OS.

CONCLUSION

Radiation therapy is associated with improved overall survival in elderly patients with localized extremity STSs. These findings suggest that radiation therapy should be considered as a key component of the treatment strategy for this patient population, taking into account individual patient characteristics and comorbidities.

MRI of Soft-Tissue Tumors: What to Include in the Report

MRI serves as a critical step in the workup, local staging, and treatment planning of extremity soft-tissue masses. For the radiologist to meaningfully contribute to the management of soft-tissue masses, they need to provide a detailed list of descriptors of the lesion outlined in an organized report. While it is occasionally possible to use MRI to provide a diagnosis for patients with a mass, it is more often used to help with determining the differential diagnosis and planning of biopsies, surgery, radiation treatment, and chemotherapy (when provided). Each descriptor on the list outlined in this article is specifically aimed to assist in one or more facets of the overall approach to soft-tissue masses. This applies to all masses, but in particular sarcomas. Those descriptors are useful to help narrow the differential diagnosis and ensure concordance with a pathologic diagnosis and its accompanying grade assignment of soft-tissue sarcomas. These include a lesion's borders and shape, signal characteristics, and contrast enhancement pattern; the presence of peritumoral edema and peritumoral enhancement; and the presence of lymph nodes. The items most helpful in assisting surgical planning include a lesion's anatomic location, site of origin, size, location relative to a landmark, relationship to adjacent structures, and vascularity including feeding and draining vessels. The authors provide some background information on soft-tissue sarcomas, including their diagnosis and treatment, for the general radiologist and as a refresher for radiologists who are more experienced in tumor imaging. ©RSNA, 2024 See the invited commentary by Murphey in this issue.

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.

Partially Ablative Body Radiotherapy (PABR): A novel approach for palliative radiotherapy of locally advanced bulky unresectable sarcomas

BACKGROUND

Locally advanced, bulky, unresectable sarcomas cause significant tumour mass effects, leading to burdensome symptoms. We have developed a novel Partially Ablative Body Radiotherapy (PABR) technique that delivers a high, ablative dose to the tumour core and a low, palliative dose to its periphery aiming to increase overall tumour response without significantly increasing treatment toxicity.

AIM

This study aims to report the safety and oncologic outcomes of PABR in patients with bulky, unresectable sarcomas.

METHODS AND MATERIALS

A total of 18 patients with histologically proven sarcoma treated with PABR from January 2020 to October 2023 were retrospectively reviewed. The primary endpoints were symptomatic and structural response rates. Secondary endpoints were overall survival, freedom from local progression, freedom from distant progression, and acute and late toxicity rates.

RESULTS

All patients had tumours ≥5 cm with a median tumour volume of 985 cc, and the most common symptom was pain. The median age is 72.5 years and 44.5 % were ECOG 2-3. The most common regimen used was 20 Gy in 5 fractions with an intratumoral boost dose of 50 Gy (83.3 %). After a median follow-up of 11 months, 88.9 % of patients exhibited a partial response with a mean absolute tumour volume reduction of 49.5 %. All symptomatic patients experienced symptom improvement. One-year OS, FFLP and FFDP were 61 %, 83.3 % and 34.8 %, respectively. There were no grade 3 or higher toxicities.

CONCLUSION

PABR for bulky, unresectable sarcomas appears to be safe and may provide good symptomatic response, tumour debulking, and local control. Further study is underway.

Spot scanning proton therapy for unresectable bulky retroperitoneal dedifferentiated liposarcoma: a case report

The development of effective treatment strategies for unresectable retroperitoneal sarcoma is desirable. Herein, we suggest that definitive proton therapy (PT) could be a promising treatment option, regardless of the large size of the tumor. A 52-year-old man presented with a discomfort of the lower abdomen. Computed tomography revealed a retroperitoneal tumor, measuring over 20 cm in the largest dimensions, which was surrounded by the gastrointestinal (GI) tract. Biopsy revealed dedifferentiated liposarcoma. Neoadjuvant chemotherapy was ineffective, and the tumor was ultimately deemed unresectable. The patient opted to receive PT instead of continuation of chemotherapy. Spot scanning PT (SSPT) at a total dose of 60.8 Gy (relative biological effectiveness) in 16 fractions was employed. SSPT administered a dose to the tumor while successfully sparing the surrounding GI tract. He did not receive any maintenance systemic therapy after PT. The tumor gradually shrunk over more than 7 years, with no evidence of recurrence outside the irradiation field. The initial measurable tumor volume of 2925 cc decreased to 214 cc at the final follow-up, seven and a half years after PT. The patient is alive without any severe complications.

Novel Definitive Hypofractionated Accelerated Radiation Dose-painting (HARD) for Unresected Soft Tissue Sarcomas

Purpose

Soft tissue sarcomas (STS) are historically radioresistant, with surgery being an integral component of their treatment. With their low α/β, STS may be more responsive to hypofractionated radiation therapy (RT), which is often limited by long-term toxicity risk to surrounding normal tissue. An isotoxic approach using a hypofractionated accelerated radiation dose-painting (HARD) regimen allows for dosing based on clinical risk while sparing adjacent organs at risk.

Methods and Materials

We retrospectively identified patients from 2019 to 2022 with unresected STS who received HARD with dose-painting to high, intermediate, and low-risk regions of 3.0 Gy, 2.5 Gy, and 2.0 to 2.3 Gy, respectively, in 20 to 22 fractions. Clinical endpoints included local control, locoregional control, progression free survival, overall survival, and toxicity outcomes.

Results

Twenty-seven consecutive patients were identified and had a median age of 68 years and tumor size of 7.0 cm (range, 1.2-21.0 cm). Tumors were most often high-grade (70%), stage IV (70%), located in the extremities (59%), and locally recurrent (52%). With a median follow-up of 33.4 months, there was a 3-year locoregional control rate of 100%. The 3-year overall and progression-free survival were 44.9% and 23.3%, respectively. There were 5 (19%) acute and 2 (7%) late grade 3 toxicities, and there were no grade 4 or 5 toxicities at any point.

Conclusions

The HARD regimen is a safe method of dose-escalating STS, with durable 3-year locoregional control. This approach is a promising alternative for unresected STS, though further follow-up is required to determine long-term control and toxicity.

Extremity and Truncal Soft Tissue Sarcoma: Risk Assessment and Multidisciplinary Management

Extremity and truncal soft tissue sarcomas are a heterogeneous group of rare cancers that arise from mesenchymal tissues. Hence, the adoption of tailored risk assessment and prognostication tools plays a crucial role in optimizing the decision-making for which of the many possible treatment strategies to select. Management of these tumors requires a multidisciplinary strategy, which has seen significant development in recent decades. Surgery has emerged as the primary treatment approach, with the main goal of achieving microscopic negative tumor margins. To reduce the likelihood of local recurrence, loco-regional treatments such as radiation therapy and isolated limb perfusion are often added to the treatment regimen in combination with surgery. This approach also enables surgeons to perform limb-sparing surgery, particularly in cases where a positive tumor margin is expected. Chemotherapy may also provide a further benefit in decreasing the probability of local recurrence or reducing distant metastasis in selected patients. Selecting the optimal treatment strategy for these rare tumors is best accomplished by an experienced multi-disciplinary team.

Spatially Fractionated Radiation Therapy in Sarcomas: A Large Single-Institution Experience

Purpose

Spatially fractionated radiation therapy (SFRT) is a recognized technique for enhancing tumor response in radioresistant and bulky tumors. We analyzed clinical and treatment outcomes in patients with bone and soft tissue sarcomas treated with modern SFRT techniques.

Methods and Materials

Patients with metastatic or unresectable sarcoma treated with brass collimator, volumetric modulated arc therapy lattice, or proton SFRT from December 2019 to June 2022 were retrospectively reviewed. Consolidative external beam radiation therapy (EBRT) was delivered at the physician's discretion. Patient and treatment characteristics, treatment response (symptom improvement, local control, and imaging response), and toxicity data were collected.

Results

The cohort consisted of 53 patients treated with 61 SFRT treatments. Median age at treatment was 60.0 years. The primary location was soft tissue in 46 courses (75%) and bone in 15 (25%). Fifty-three courses (87%) were treated for symptom relief. The most used SFRT technique was volumetric modulated arc therapy lattice (n = 52, 85%) to a dose of 20 Gy (n = 48, 79%; range, 16-20 Gy). EBRT was delivered post-SFRT in 55 (90%) treatment courses with a median time interval from SFRT to EBRT of 5 days (range, 0-14 days). Median physical EBRT dose and fractionation was 40 Gy (range, 9-73.5 Gy) and 10 fractions (range, 3-33 fractions). Median follow up was 7.4 months (range, 0.2-30 months). One-year overall survival and local control rates were 53% and 82%. Symptom relief was documented with 32 treatment courses (60%). Stable or partial response was observed with 47 treatment courses (90%). Four grade 3 to 4 acute and subacute toxicities were attributable to SFRT (8%).

Conclusions

The current series is the largest to date documenting outcomes for SFRT in sarcomas. Our results suggest combined SFRT with EBRT is associated with a favorable toxicity profile and high rates of symptomatic and radiographic responses for metastatic or unresectable sarcomas.

Management of oligometastatic/metastatic sarcomas and place of local treatments with focus on modern radiotherapy approaches

Soft tissue sarcomas are a rare and heterogeneous disease. For localized disease, treatment is based on surgery and radiotherapy with or without chemotherapy depending on risk factors. Upfront metastases are present in 7 to 20% of cases, and are localized to the lungs in most of cases. Disseminated disease is generally considered incurable but in selected cases, aggressive local treatment of metastases allowed long survival. Treatment of primary tumour is often debated. Our purpose is to evaluate the literature concerning the role of radiotherapy in the management of primary metastatic soft tissue sarcomas.

Complete metabolic response after Partially Ablative Radiotherapy (PAR) for bulky retroperitoneal liposarcoma: A case report

In the management of symptomatic inoperable retroperitoneal sarcomas (RPS), palliative radiotherapy (RT) is a potential treatment option. However, the efficacy of low doses used in palliative RT is limited in these radioresistant tumors. Therefore, exploring dose escalation strategies targeting specific regions of the tumor may enhance the therapeutic effect of RT in relieving or preventing symptoms. In this case report, we present the case of an 87-year-old patient with rapidly growing undifferentiated liposarcoma in the retroperitoneum, where surgical and systemic therapies were ruled out due to age and comorbidities. RT was administered using volumetric modulated arc therapy, delivering 20 Gy in 4 fractions twice daily to the macroscopic tumor and 40 Gy in 4 fractions twice daily (simultaneous integrated boost) to the central part of the tumor (Gross Tumor Volume minus 2 cm). An 18F-FDG-PET-CT scan performed after RT demonstrated a complete metabolic response throughout the entire tumor mass. Although the patient eventually succumbed to metastatic spread to the bone, liver, and lung after 9 months, no local disease progression or pain/obstructive symptoms were observed. This case highlights the technical and clinical feasibility of delivering ablative doses of RT to the central region of the tumor and suggests the potential for achieving a complete metabolic response and durable tumor control.

Updated Review and Clinical Recommendations for the Diagnosis and Treatment of Patients with Retroperitoneal Sarcoma by the Spanish Sarcoma Research Group (GEIS)

Soft tissue sarcomas (STS) are an uncommon and biologically heterogeneous group of tumors arising from mesenchymal cells. The incidence is estimated at five cases per 100,000 people per year. Retroperitoneal sarcomas (RPS) account for 10-15% of all STS, and their management depends on their anatomical characteristics and histotype. Due to their very low incidence, it is recommended that RPS be treated in reference centers and evaluated by an experienced multidisciplinary team (MDT). In Spain, the Spanish Group for Research in Sarcomas (GEIS) brings together experts from various specialties to promote research on sarcomas and improve treatment results. This paper summarizes the GEIS recommendations for the diagnosis, treatment, and follow-up of patients with RPS.

Trimodality Treatment of Extremity Soft Tissue Sarcoma: Where Do We Go Now?

OPINION STATEMENT

Extremity soft tissue sarcoma (ESTS) constitutes the majority of patients with soft tissue sarcoma (STS). Patients with localized high-grade ESTS > 5 cm in size carry a substantial risk of developing distant metastasis on follow-up. A neoadjuvant chemoradiotherapy approach can enhance local control by facilitating resection of the large and deep locally advanced tumors while trying to address distant spread by treating the micrometastasis for these high-risk ESTS. Preoperative chemoradiotherapy and adjuvant chemotherapy are often used for children with intermediate- or high-risk non-rhabdomyosarcoma soft tissue tumors in North America and Europe. In adults, the cumulative evidence supporting preoperative chemoradiotherapy or adjuvant chemotherapy remains controversial. However, some studies support a possible benefit of 10% in overall survival (OS) for high-risk localized ESTS, especially for those with a probability of 10-year OS < 60% using validated nomograms. Opponents of neoadjuvant chemotherapy argue that it delays curative surgery, compromises local control, and increases the rate of wound complications and treatment-related mortality; however, the published trials do not support these arguments. Most treatment-related side effects can be managed with adequate supportive care. A coordinated multidisciplinary approach involving sarcoma expertise in surgery, radiation, and chemotherapy is required to achieve better outcomes for ESTS. The next generation of clinical trials will shed light on how comprehensive molecular characterization, targeted agents and/or immunotherapy can be integrated into the upfront trimodality treatment to improve outcomes. To that end, every effort should be made to enroll these patients on clinical trials, when available.

The importance of surgical resection in the management of rectal sarcoma: A national cancer database analysis of 133 cases

BACKGROUND AND PURPOSE

Rectal sarcomas (RS) are rare malignant tumors with a very poor prognosis. This study aimed to assess the characteristics, treatment, and outcomes of RS in the United States.

METHODS

This study was a retrospective analysis of the National Cancer Database (NCDB) from 2004 to 2019 of patients with a diagnosis of RS. The main outcome measures were overall survival (OS) and its predictors.

RESULTS

133 RS patients (39.1% female) with a mean age of 65.7 ± 15.6 years were included in the study. Mean tumor size was 6.1 ± 3 cm. The crude OS rate was 22.5% and median survival duration was 10.1 (IQR: 3.2-21) months. Factors associated with an improved OS on were private insurance (HR = 0.23, p = 0.001) and undergoing surgery (HR 0.23, p < 0.001), Factors associated with poor survival were age (HR 1.02, p = 0.005), male sex (HR 2.27, p = 0.001), Charlson score of 3 (HR 5.17, p = 0.003), and positive resection margins (HR: 2.64, p = 0.01). Multivariate Cox regression analysis revealed that male sex (HR 2.16, p = 0.04) and positive resection margins (HR 2.31, p = 0.03) were predictors of poor survival whereas surgery was an independent predictor of improved OS (HR 0.321, p < 0.001) CONCLUSIONS: RS is a very rare rectal malignancy with an even poorer prognosis than previously reported. However, undergoing surgery with curative intent while obtaining negative margins may confer better OS.

Efficacy and safety of carbon ion radiotherapy for bone sarcomas: a systematic review and meta-analysis

Objective

This study aimed to systematically evaluate and conduct a meta-analysis of the efficacy and safety of carbon ion radiotherapy for bone sarcomas.

Methods

We searched for articles using the PubMed, Embase, Cochrane Library, and the Web of Science databases from their inception to January 12, 2022. Two researchers independently screened the literature and extracted data based on the inclusion and exclusion criteria. Statistical analyses were performed using STATA version 14.0.

Results

We searched for 4378 candidate articles, of which 12 studies were included in our study according to the inclusion and exclusion criteria. Of the 897 BSs patients who received carbon ion radiotherapy in the studies, 526 patients had chordoma, 255 patients had chondrosarcoma, 112 patients had osteosarcoma, and 4 patients had other sarcomas. The local control rate at 1, 2, 3, 4, 5, and 10 years in these studies were 98.5% (95% confidence interval [CI] = 0.961–1.009, I² = 0%), 85.8% (95% CI = 0.687–1.030, I² = 91%), 86% (95% CI = 0.763–0.957, I² = 85.3%), 91.1% (95% CI = 0.849–0.974), 74.3% (95% CI = 0.666–0.820, I² = 85.2%), and 64.7% (95% CI = 0.451–0.843, I² = 95.3%), respectively. The overall survival rate at 1, 2, 3, 4, 5, and 10 years in these studies were 99.9% (95% CI = 0.995–1.004, I² = 0%), 89.6% (95% CI = 0.811–0.980, I² = 96.6%), 85% (95% CI = 0.750–0.950, I² = 89.4%), 92.4% (95% CI = 0.866–0.982), 72.7% (95% CI = 0.609–0.844, I² = 95.3%), and 72.1% (95% CI = 0.661–0.781, I² = 46.5%), respectively. Across all studies, the incidence of acute and late toxicities was mainly grade 1 to grade 2, and grade 1 to grade 3, respectively.

Conclusion

As an advanced radiotherapy, carbon ion radiotherapy is promising for patients with bone sarcomas that are unresectable or residual after incomplete surgery. The data indicated that carbon ion radiotherapy was safe and effective for bone sarcomas, showing promising results for local control, overall survival, and lower acute and late toxicity.

PROSPERO registration number

CRD42021258480.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02089-0.

New school technology meets old school technique: Intensity modulated proton therapy and laparoscopic pelvic sling facilitate safe and efficacious treatment of pelvic sarcoma

Purpose

Small bowel tolerance may be dose-limiting in the management of some pelvic and abdominal malignancies with curative-intent radiation therapy. Multiple techniques previously have been attempted to exclude the small bowel from the radiation field, including the surgical insertion of an absorbable mesh to serve as a temporary pelvic sling. This case highlights a clinically meaningful application of this technique with modern radiation therapy.

Methods and Materials

A patient with locally invasive, unresectable high-grade sarcoma of the right pelvic vasculature was evaluated for definitive radiation therapy. The tumor immediately abutted the small bowel. The patient underwent laparoscopic placement of a mesh sling to retract the abutting small bowel and subsequently completed intensity modulated proton therapy.

Results

The patient tolerated the mesh insertion procedure and radiation therapy well with no significant toxic effects. The combination approach achieved excellent dose metrics, and the patient has no evidence of progression 14 months out from treatment.

Conclusions

The combination of mesh as a pelvic sling and proton radiation therapy enabled the application of a curative dose of radiation therapy and should be considered for patients in need of curative-intent radiation when the bowel is in close proximity to the target.

Is there a place for definitive radiotherapy in the treatment of unresectable soft-tissue sarcoma? A systematic review

BACKGROUND

Definitive external beam radiotherapy (EBRT) is an unusual treatment of unresectable soft-tissue sarcomas (STS). Recent technical innovations and physical advantages of particle therapies may improve results of this therapeutic option. The role of this review was to report the clinical results of photon- and particle-based EBRT in unresectable STS.

MATERIAL AND METHODS

We performed a systematic review of the literature on Pubmed database to identify studies investigating the efficacy and safety of EBRT. The primary endpoint was local control (LC) and secondary endpoints were progression-free survival (PFS), overall survival (OS) and adverse events in a subset of patients with gross disease STS.

RESULTS

We identified 29 studies involving 1409 patients (pts) evaluating photon (n = 18; 956 pts), proton (n = 1; 21 pts), carbon ion (n = 2; 152 pts), neutron (n = 7; 259 pts) or pion (n = 1; 21 pts) therapy. Definitive EBRT achieves valuable 5-year LC rates of 28-73% with photon and 52-69% with particle therapies. Most local failures (66-100%) occurred within 3 years. Long-term disease control can be achieved in a fraction of patients, with 5-year PFS and OS of 0-39% and 24.7-63%, respectively. The rate of severe adverse events was highly variable with photons, <15% in proton and carbon ion therapy, whereas 25 to 50% of patients treated with neutrons and pions presented severe AE. While a dose higher or equal 64 Gy seem to improve the prognosis, delivering a dose higher or equal 68 Gy dramatically increases severe adverse events.

CONCLUSION

Definitive EBRT with dose 64-66 Gy seems to be a safe and efficient treatment for unresectable STS. Future clinical trials should assess the potential of biomarkers of response, thus identifying patients that could benefit from local treatment.

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.

Long-term outcomes after definitive radiotherapy with modern techniques for unresectable soft tissue sarcoma

INTRODUCTION

The use of definitive radiotherapy (dRT) in unresectable soft-tissue sarcomas (STS) is still controversial and recent data are scarce. We report clinical results of this therapeutic option.

METHODS

We retrospectively included STS patients treated between 2009 and 2020, with dRT for unresectable or with a measurable residual disease after R2 surgery. Response rate, local failure (LF), progression-free survival (PFS) and overall survival (OS) were evaluated.

RESULTS

116 patients with localized/locally advanced STS were treated from 2009 to 2020, with a median age of 71 years (range 18-92). Most tumors were deep-seated (96.6%), grade 2-3 (85.1%), located in the trunk or extremities (74.2%). Helical tomotherapy, volumetric modulated arc therapy, or stereotactic radiotherapy was performed in 39.7%, 19% and 8.6% of patients, respectively. The median equivalent dose in 2 Gy fractions (EQD2) was 60 Gy (IQR 52-65). At first follow-up, 66 (58.9%) and 25 (22%) patients had stable disease and partial response. After a median follow-up of 54.8 months (IQR 40.3-95.4), 3-year LF, PFS and OS were 43.2%, 16.6% and 34%, respectively. Median OS was 21.4 months (95%CI 14-26). The multivariate analysis identified grade 3 and AJCC T3-T4 stage to be associated with both shorter PFS and OS (all p<0.001). Macroscopically incomplete resection and EQD2 ≥64Gy were associated with better OS (p=0.016 and p=0.007). Acute and late severe adverse events occurred in 24 (19.7%) and 5 (4.3%) patients.

CONCLUSION

In unresectable STS patients, definitive modern radiotherapy is a safe and effective treatment yielding long term control in selected patients.

Efficacy and Safety of Radioactive 125I Seed Implantation for Patients with Oligo-Recurrence Soft Tissue Sarcomas

PURPOSE

To evaluate the efficacy and safety of computed tomography-guided radioactive iodine-125 (¹²⁵I) seed implantation for oligo-recurrence soft tissue sarcomas following surgical resection.

MATERIALS AND METHODS

Patients with oligo-recurrence soft tissue sarcomas after curative surgical resection between June 2013 and December 2020 were included. The primary outcome measure was objective response rate according to the Response Evaluation Criteria in Solid Tumors (RECIST 1.1). The secondary outcomes included progression-free survival, overall survival, and safety profiles.

RESULTS

Twenty-nine patients receiving computed tomography-guided ¹²⁵I seed implantation were included in the study. The objective response rates at 2-, 6- and 12-month follow-up were 48.3%, 65.5% and 40.9%, respectively. The median progression-free survival was 11.3 months. The median overall survival was 25.1 months, with a 1- and 2-year overall survival rate of 81.5% and 50.0%, respectively. No severe treatment-related adverse effects occured.

CONCLUSION

¹²⁵I seed implantation has the potential to be an effective and safe treatment for oligo-recurrence soft tissue sarcomas after surgical resection.

Three cases of retroperitoneal sarcoma in which bioabsorbable spacers (bioabsorbable polyglycolic acid spacers) were inserted prior to carbon ion radiotherapy

From August 2019 to August 2020, we inserted polyglycolic acid (PGA) spacers and administered carbon ion radiotherapy (CIRT) to three cases of retroperitoneal sarcoma at our hospital. We aimed to investigate its utility and safety for retroperitoneal sarcoma. We analyzed changes in PGA spacer volume and corresponding computed tomography (CT) values in addition to the dose distribution using in-room CT images that were obtained during treatment. We assessed adverse events and investigated the suitability, safety and effectivity of PGA spacer insertion. During treatment, changes in PGA spacer volumes and CT values were confirmed. Volumes increased in patients with a folded PGA spacer, and it increased 1.6-fold by the end of irradiation compared with planning CT. The CT values decreased by 20-50 Hounsfield units at the end of irradiation compared to the planning CT. Dose distribution evaluation showed that the dose to the gastrointestinal tract adjacent to the tumor was maintained below the tolerable dose, and a sufficient dose was delivered to the target by PGA spacer insertion. One case of subileus caused during abdominal surgery for PGA spacer insertion occurred. No other adverse events, such as digestive disorders, were observed. CIRT with PGA spacer insertion for retroperitoneal sarcomas is safe and effective. For cases in which there is no option but to perform irradiation using a PGA spacer, precautionary measures such as verification of dose distributions using CT images are necessary.

An International Consensus on the Design of Prospective Clinical-Translational Trials in Spatially Fractionated Radiation Therapy

PURPOSE

Spatially fractionated radiation therapy (SFRT), which delivers highly nonuniform dose distributions instead of conventionally practiced homogeneous tumor dose, has shown high rates of clinical response with minimal toxicities in large-volume primary or metastatic malignancies. However, prospective multi-institutional clinical trials in SFRT are lacking, and SFRT techniques and dose parameters remain variable. Agreement on dose prescription, technical administration, and clinical and translational design parameters for SFRT trials is essential to enable broad participation and successful accrual to rigorously test the SFRT approach. We aimed to develop a consensus for the design of multi-institutional clinical trials in SFRT, tailored to specific primary tumor sites, to help facilitate development and enhance the feasibility of such trials.

METHODS AND MATERIALS

Primary tumor sites with sufficient pilot experience in SFRT were identified, and fundamental trial design questions were determined. For each tumor site, a comprehensive consensus effort was established through disease-specific expert panels. Clinical trial design criteria included eligibility, SFRT technology and technique, dose and fractionation, target- and normal-tissue dose parameters, systemic therapies, clinical trial endpoints, and translational science considerations. Iterative appropriateness rank voting, expert panel consensus reviews and discussions, and public comment posting were used for consensus development.

RESULTS

Clinical trial criteria were developed for head and neck cancer and soft-tissue sarcoma. Final consensus among the 22 trial design categories each (a total of 163 criteria) was high to moderate overall. Uniform patient cohorts of advanced bulky disease, standardization of SFRT technologies and dosimetry and physics parameters, and collection of translational correlates were considered essential to trial design. Final guideline recommendations and the degree of agreement are presented and discussed.

CONCLUSIONS

This consensus provides design guidelines for the development of prospective multi-institutional clinical trials testing SFRT in advanced head and neck cancer and soft-tissue sarcoma through in-advance harmonization of the fundamental clinical trial design among SFRT experts, potential investigators, and the SFRT community.

Clinical outcome in patients who underwent amputation due to extremity soft tissue sarcoma: Tokai Musculoskeletal Oncology Consortium study

BACKGROUND

Soft tissue sarcomas are a diverse group of rare malignant tumours, mostly occurring in the lower extremities. Amputations are necessary for achieving local control when the soft tissue sarcomas are too large and/or have neurovascular involvement. Patients who require amputation have a poorer prognosis than those who undergo limb-salvage surgery.

PATIENTS AND METHODS

We investigated the tumour characteristics and the clinical outcomes in 55 patients with primary soft tissue sarcomas, who underwent amputation. We excluded patients with amputation performed distal to the wrist or ankle joints and those with recurrent soft tissue sarcomas.

RESULTS

The mean tumour size was 11.1 cm. Hip disarticulation was performed in 6 patients, 20 underwent above the knee amputation, 8 underwent knee disarticulation and 12 underwent below the knee amputation. Shoulder disarticulation was performed in three patients, five underwent above the elbow amputation, and one underwent below the elbow amputation. The 5-year disease-specific survival rate was 52.8%. The 5-year recurrence-free survival rate and 5-year metastasis-free survival rates were 90.1% and 38.5%, respectively. Larger tumour size, age and the distant metastases at first presentation were predictors of poor prognosis for survival in multivariate analysis. Twenty-eight patients could walk using artificial limbs. The level of amputation (above versus below the knee) showed a significant difference in achieving independent gait.

CONCLUSION

Amputation is a useful treatment option for achieving local control in patients with large soft tissue sarcomas. Patients had an opportunity of walking, especially for those who underwent below the knee amputation.

A risk factor analysis for local recurrence of bone and soft tissue sarcoma treated with carbon ion radiotherapy: A retrospective cohort study at a single institution

AIM

Carbon ion radiotherapy is well-recognized as an excellent radiation modality that is suitable for treating unresectable bone and soft-tissue sarcoma of the trunk, spine, and pelvis; however, further study is needed to improve the local control rate. The current study examined the risk factors of the local recurrence of sarcomas after carbon ion radiotherapy.

METHODS

Patients with inoperable bone and soft-tissue sarcomas treated with carbon ion radiotherapy in our institute from 2010 to 2018 were retrospectively analyzed. Among them, 87 patients were eligible for this study. We divided the instances of local recurrence into two types, in-field and out-field recurrence, and evaluated the predictors for the risk of local recurrence such as the age at the treatment, sex, histopathological diagnosis, standard uptake value on fluorodeoxyglucose positron emission tomography, and the clinical target volume for each recurrence using a Cox proportional hazards model.

RESULTS

A multivariate analysis revealed that the tumors with a post-treatment standard uptake value of more than 3.84 on positron emission tomography had a significantly high risk of in-field recurrence (hazard ratio, 3.42; p = .03). Furthermore, postoperative lesions were a risk factor for out-field recurrence (hazard ratio, 3.82; p < .01).

CONCLUSION

The current study revealed that sarcomas maintaining a high glucose metabolic activity after carbon ion radiotherapy carried a risk of in-field recurrence, and the most significant risk factor of out-field recurrence was identified to be surgery before CIRT.

Local Control For High-Grade Nonrhabdomyosarcoma Soft Tissue Sarcoma Assigned to Radiation Therapy on ARST0332: A Report From the Childrens Oncology Group

PURPOSE

The ARST0332 trial for pediatric and young adults with nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) used risk-based treatment including primary resection with lower-than-standard radiation doses to optimize local control (LC) while minimizing long-term toxicity in those requiring radiation therapy (RT). RT for high-grade NRSTS was based on extent of resection (R0: negative margins, R1: microscopic margins, R2/U: gross disease/unresectable); those with >5 cm tumors received chemotherapy (CT; ifosfamide/doxorubicin). This analysis evaluates LC for patients assigned to RT and prognostic factors associated with local recurrence (LR).

METHODS AND MATERIALS

Patients aged <30 years with high-grade NRSTS received RT (55.8 Gy) for R1 ≤5 cm tumor (arm B); RT (55.8 Gy)/CT for R0/R1 >5 cm tumor (arm C); or neoadjuvant RT (45 Gy)/CT plus delayed surgery, CT, and postoperative boost to 10.8 Gy R0 <5 mm margins/R1 or 19.8 Gy for R2/unresected tumors (arm D).

RESULTS

One hundred ninety-three eligible patients had 24 LRs (arm B 1/15 [6.7%], arm C 7/65 [10.8%], arm D 16/113 [14.2%]) at median time to LR of 1.1 years (range, 0.11-5.27). Of 95 eligible for delayed surgery after neoadjuvant therapy, 89 (93.7%) achieved R0/R1 margins. Overall LC after RT were as follows: R0, 106 of 109 (97%); R1, 51 of 60 (85%); and R2/unresectable, 2 of 6 (33%). LR predictors include extent of delayed resection (P <.001), imaging response before delayed surgery (P < .001), histologic subtype (P <.001), and no RT (P = .046). The 5-year event-free survival was significantly lower (P = .0003) for patients unable to undergo R0/R1 resection.

CONCLUSIONS

Risk-based treatment for young patients with high-grade NRSTS treated on ARST0332 produced very high LC, particularly after R0 resection (97%), despite lower-than-standard RT doses. Neoadjuvant CT/RT enabled delayed R0/R1 resection in most patients and is preferred over adjuvant therapy due to the lower RT dose delivered.

The Feasibility Study of Hypofractionated Radiotherapy with Regional Hyperthermia in Soft Tissue Sarcomas

Simple Summary

The recommended management of marginally resectable or unresectable soft tissue sarcomas is an attempt of neoadjuvant therapy. The use of neoadjuvant chemotherapy is limited in low-grade tumors, sarcomas with chemoresistant pathology or in unfit patients. There is a growing evidence on hypofractionated radiotherapy in soft tissue sarcomas, but its efficacy may be limited by radioresistance that is frequently associated with chemoresistance. Regional hyperthermia is a potent and minimally invasive radiosensitizer. We aimed to investigate the feasibility of moderately hypofractionated radiotherapy combined with regional hyperthermia in aforementioned clinical situations. Our findings indicate that proposed combination is feasible while maintaining good short-term local efficacy and tolerance. It could serve as a basis for further studies on radiotherapy with hyperthermia in soft tissue sarcomas.

Abstract

Introduction: Management of marginally resectable or unresectable soft tissue sarcomas (STS) in patients who are not candidates for neoadjuvant chemotherapy due to chemoresistant pathology or contraindications remains a challenge. Therefore, in these indications, we aimed to investigate a feasibility of 10x 3.25 Gy radiotherapy combined with regional hyperthermia (HT) that could be followed by surgery or 4x 4 Gy radiotherapy with HT. Materials and methods: We recruited patients with locally advanced marginally resectable or unresectable STS who (1) presented chemoresistant STS subtype, or (2) progressed after neoadjuvant chemotherapy, or (3) were unfit for chemotherapy. The primary endpoint was the feasibility of the proposed regimen. Results: Thirty patients were enrolled. All patients received the first part of the treatment, namely radiotherapy with HT. Among them, 14 received the second part of radiotherapy with HT whereas 13 patients underwent surgery. Three patients did not complete the treatment protocol. The feasibility criteria were fulfilled in 90% of patients. Two patients developed distant metastases. One patient died due to distant progression. One patient developed rapid local recurrence after surgery. Conclusions: Hypofractionated radiotherapy with HT is a feasible treatment for marginally resectable or unresectable STS in patients who are not candidates for chemotherapy. Results of this clinical trial support the further validation of RT and HT combinations in STS.

Sarcoma of the Heart Treated with Stereotactic MR-Guided Online Adaptive Radiation Therapy

We present the first case in the literature of a patient with a histology-proven intimal sarcoma of the heart, recurrent after surgery, treated with stereotactic MR-guided online adaptive radiation therapy on an MR-Linac machine. The treatment was feasible and well tolerated. The CT scan 6 months after the last treatment showed stable disease.

Local control and postponement of systemic therapy after modest dose radiotherapy in oligometastatic myxoid liposarcomas

INTRODUCTION

Oligometastatic disease and/or oligoprogression in myxoid liposarcoma(oMLS) triggers discussions on local treatment options and delay of systemic treatments. We hypothesized that satisfactory local control and postponement of systemic therapy could be achieved with a modest radiotherapy(RT) dose in oMLS.

METHODS

The DOREMY trial is a multicenter, phase 2 trial evaluating efficacy and toxicity of a modest RT dose in both localized and oMLS; this report presents the data of the oMLS cohort treated with 36 Gy in 12-18 fractions with optional subsequent metastasectomy. The primary endpoint was local progression free survival(LPFS). Secondary endpoints included postponement of systemic therapy, symptom reduction, radiological objective response, and toxicity.

RESULTS

Nine patients with a total of 25 lesions were included, with a median follow-up of 23 months. The median number of lesions per patient was three and the trunk wall and bone were the most frequently affected sites. In lesions treated with definitive RT(n = 21), LPFS rates at 1, 2, and 3 years were respectively 73%, 61%, and 40%. Radiological objective response and clinical symptom reduction were achieved in 8/15(53%) and 9/10(90%) of the evaluable lesions, respectively. No local recurrences occurred in lesions treated with RT and metastasectomy(n = 4). For the entire study population, the median postponement of systemic therapy was 10 months. Grade ≥ 2 toxicity was observed in 2/9(22%) of patients.

CONCLUSIONS

This trial suggests that 36 Gy could possibly be effective to achieve local control, postpone systemic therapy and reduce symptoms in oMLS. Given the minimal toxicity this treatment could be reasonably considered in oMLS.

Molecular Aspects of the Isolated Limb Infusion Procedure

For decades, isolated limb infusion (ILI) and hyperthermic isolated limb perfusion (HILP) have been used to treat melanoma in-transit metastases and unresectable sarcoma confined to the limb utilizing the effect of loco-regional high-dose chemotherapy to the isolated limb. Both procedures are able to provide high response rates in patients with numerous or bulky lesions in whom other loco-regional treatments are becoming ineffective. In comparison to systemic therapies, on the other hand, ILI and HILP have the advantage of not being associated with systemic side-effects. Although in principle ILI and HILP are similar procedures, ILI is technically simpler to perform and differs from HILP in that it takes advantage of the hypoxic and acidotic environment that develops in the isolated limb, potentiating anti-tumour activity of the cytotoxic agents melphalan +/− actinomycin-D. Due to its simplicity, ILI can be used in both preclinical and clinical studies to test new cytotoxic regimens and combinations with the aim to overcome tumour resistance. In the future, administration of cytotoxic agents by ILI, in combination with systemic treatments such as BRAF/MEK/KIT inhibitors, immunotherapy (CTLA-4 blockade), and/or programmed death (PD-1) pathway inhibitors, has the potential to improve responses further by inducing increased tumour cell death while limiting the ability of the tumour to suppress the immune response.

Definitive Radiotherapy in the Management of Non-Resectable or Residual Retroperitoneal Sarcomas: Institutional Cohort Analysis and Systematic Review

BACKGROUND

There is currently no consensus on optimal management of patients with primary or recurrent non-resectable/residual retroperitoneal sarcomas (RPS). The objective of this study was to document the outcomes of patients with primary or recurrent non-resectable/residual RPS treated in our center with definitive radiotherapy (RT) and to perform a systematic review on the topic.

METHODS

A retrospective analysis of consecutive RPS patients treated in our center between 2000 and 2019 was performed. All consecutive patients who underwent definitive conformal RT with image guidance for primary or recurrent non-resectable or macroscopically residual RPS were included. Additionally, a systematic review compliant with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses was performed.

RESULTS

The study enrolled 14 patients who met the aforementioned criteria. Data on clinicopathological characteristics, RT and response to treatment were assessed. RT allowed achieving prolonged local control of the disease, i.e. no local progression of the disease for more than 12 months after RT in 10 patients. Local control lasted more than 24 months in 6 cases, with minimal or no toxicity. A systemic review of 11 studies revealed concordance of our results with previous reports of primary or recurrent non-resectable/residual RPS.

CONCLUSIONS

RT provided satisfactory local disease control with acceptable treatment tolerance in patients with primary or recurrent non-resectable/residual RPS and represents a valuable treatment modality in the selected group of patients. Additional RT modalities i.e. BT, particle therapy, MRI-guided RT, or GRID/Lattice RT may be introduced to improve local control and further minimize toxicity.

Soft Tissue Sarcoma Follow-up Imaging: Strategies to Distinguish Post-treatment Changes from Recurrence

Soft tissue sarcomas encompass multiple entities with differing recurrence rates and follow-up intervals. The detection of recurrences and their differentiation from post-therapeutic changes is therefore complex, with a central role for the clinical radiologist. This article describes approved recommendations. Prerequisite is a precise knowledge of the current clinical management and surgical techniques. We review recurrence rates and treatment modalities. An adequate imaging technique is paramount, and comparison with previous imaging is highly recommended. We describe time-dependent therapy-related complications on magnetic resonance imaging compared with the spectrum of regular post-therapeutic changes. Early complications such as seromas, hematomas, and infections, late complications such as edema and fibrosis, and inflammatory pseudotumors are elucidated. The appearance of recurrences and radiation-associated sarcomas is contrasted with these changes. This systematic approach in follow-up imaging of soft tissue sarcoma patients will facilitate the differentiation of post-therapeutic changes from recurrences.

A multi-institutional phase 2 trial of stereotactic body radiotherapy in the treatment of bone metastases in pediatric and young adult patients with sarcoma

BACKGROUND

Metastasectomy is standard of care for pediatric patients with metastatic sarcoma with limited disease. For patients with unresectable disease, stereotactic body radiotherapy (SBRT) may serve as an alternative. Herein, the authors report the results of a prospective, multi-institutional phase 2 trial of SBRT in children and young adults with metastatic sarcoma.

METHODS

Patients aged >3 years and ≤40 years with unresected, osseous metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone were eligible. Patients received SBRT to a dose of 40 Gray (Gy) in 5 fractions. Local control (LC), progression-free survival (PFS), and overall survival (OS) were calculated using the Kaplan-Meier method.

RESULTS

Fourteen patients with a median age of 17 years (range, 4-25 years) were treated to 37 distinct metastatic lesions. With a median follow-up of 6.8 months (30.5 months in surviving patients), the Kaplan-Meier patient-specific and lesion-specific LC rates at 6 months were 89% and 95%, respectively. The median PFS was 6 months and the median OS was 24 months. In a post hoc analysis, PFS (median, 9.3 months vs 3.7 months; log-rank P = .03) and OS (median not reached vs 12.7 months; log-rank P = .02) were improved when all known sites of metastatic disease were consolidated with SBRT compared with partial consolidation. SBRT was well tolerated, with 2 patients experiencing grade 3 toxicities.

CONCLUSIONS

SBRT achieved high rates of LC in pediatric patients with inoperable metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone. These results suggest that the ability to achieve total consolidation of metastatic disease with SBRT is associated with improved PFS and OS.

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.

Space-making particle therapy for sarcomas derived from the abdominopelvic region

BACKGROUND

The primary definitive treatment for abdominopelvic sarcomas (APSs) is resection, although incomplete resection has a negative prognostic impact. Although the effectiveness of particle therapy (PT) as a treatment for APS has already been demonstrated, its application for tumors adjacent to the gastrointestinal tract is frequently restricted, due to extremely low tolerance. Space-making PT, consisting of surgical spacer placement and subsequent PT, has been developed to overcome this limitation.

MATERIALS AND METHODS

Between June 2006 and June 2018, a total of 75 patients with 12 types of APS underwent space-making PT.

RESULTS

The 3-year local control rate of all patients was 90.3%. Fourteen surgery-related complications were observed in 12 patients (16%), and complications of Grade 3b or higher were observed in 3 patients. Ninety-five PT-related complications were seen in 66 patients (88.0%), and 13 patients (17.3%) had complications of Grade 3 or higher. The median V95% (volume irradiated with 95% of the treatment planning dose) of the gross tumor volume and clinical target volume were 99.9% and 99.5%, respectively. The median D95% (dose intensity covering 95% of the target volume) of the gross tumor volume/planned dose and clinical target volume/planned dose were 99.4%, and 99.1%, respectively.

CONCLUSION

The feasibility and effectiveness of space-making PT have been demonstrated via dosimetric evaluation, and our results indicate that this new strategy may potentially provide an effective and innovative treatment option for advanced APS.

The radiation dose-response of non-retroperitoneal soft tissue sarcoma with positive margins: An NCDB analysis

OBJECTIVES

Positive margins can increase the risk of local recurrence of soft tissue sarcomas (STS). Utilizing a national registry, we investigated patterns of care and overall survival (OS) of patients with margin-positive non-retroperitoneal STS who received preoperative radiation therapy, adjuvant radiation therapy, or both.

METHODS

Adult patients with non-retroperitoneal STS who underwent resection and RT from 2004 to 2015 were included. Kaplan-Meier, log-rank analysis, and Cox regression analysis were performed.

RESULTS

We identified 5726 patients. Most had a tumor size >5 cm (60%), grade 3 disease (67%), and microscopically positive margins (57%). Compared to ≤50.4 Gy, a dose of 66 to 69.99 Gy was associated with decreased risk of death on multivariate analysis (HR 0.69, 95%; CI, 0.50-0.94). Receipt of a boost was associated with decreased risk of death on univariate analysis (HR 0.54, 95%; CI, 0.29-0.99). In patients with grade 2 to 3 tumors without the gross disease, there was an OS benefit associated with a boost on multivariate analysis (HR 0.39, 95%; CI, 0.16-0.97).

CONCLUSION

This analysis appears to show an OS benefit of dose escalation to 66 to 69 Gy for margin-positive non-retroperitoneal STS. A Postoperative boost is associated with higher OS in grade 2 to 3 STS without the gross disease.

Hypofractionated radiotherapy for non-metastatic bone and soft tissue sarcomas

PURPOSE

To evaluate the efficacy and toxicity of hypofractionated radiotherapy in non-metastatic soft tissue and bone sarcomas.

PATIENTS AND METHODS

Thirty patients underwent hypofractionated radiotherapy between 2007 and 2015. Overall, 17 patients underwent primary hypofractionated radiotherapy, nine underwent hypofractionated radiotherapy for reirradiation, and four received a boost dose via hypofractionated radiotherapy after external beam radiotherapy. Most common disease sites were head and neck and retroperitoneum. Hypofractionated radiotherapy was administered with a definitive, adjuvant, or neoadjuvant intent.

RESULTS

Median age was 37 years (range: 11-82 years). Median hypofractionated radiotherapy dose was 35Gy (range: 20-50Gy) in three to five fractions. Median follow-up was 21 months (range: 1-108 months). One- and 2-year overall survival rate was 75% and 52%, respectively. One- and 2-year local recurrence-free survival rate was 59% and 48%, with local recurrence rates of 16% and 33% in 1 and 2 years, respectively. Univariate analysis revealed tumour size (P=0.04), hypofractionated radiotherapy intent (P=0.016) and reirradiation (P=0.001) as prognostic factors for local recurrence-free survival. Severe late toxicity was observed in one patient as grade 3 trismus.

CONCLUSION

Hypofractionated radiotherapy as the primary treatment or for reirradiation has been shown to be safe in the treatment of bone and soft tissue sarcomas. It can provide relatively good local control and survival rates.

Abscopal Effect Following Proton Beam Radiotherapy in a Patient With Inoperable Metastatic Retroperitoneal Sarcoma

Background: Retroperitoneal sarcomas (RPS) are rare and primarily managed with surgery, which improves local recurrence-free and overall survival. Radiation can improve local control or provide palliation for inoperable or metastatic RPS by eliciting tumor cell death via irreparable DNA damage. In extraordinary circumstances radiation-induced cell death promotes immune-mediated regression of non-irradiated lesions in a process termed the abscopal effect. Abscopal effects are rare and incompletely understood, involving a balance of radiation's immunogenic and immunosuppressive effects. There are currently no methods to predict abscopal responses following radiotherapy. Case reports documenting post-radiotherapy abscopal effects provide additional information to better characterize these responses and to inform ongoing and future clinical trials attempting to harness radiation-induced immune responses to improve outcomes with systemic therapy, such as SARC-032, a cooperative group trial of pre-operative radiation ± pembrolizumab. We present a case of inoperable metastatic RPS treated with proton radiotherapy with complete responses of un-irradiated metastases.

Case Presentation: A 67 year-old female with inoperable metastatic unclassified round cell RPS was treated with palliative proton radiotherapy only to the primary tumor. Following completion of radiotherapy, the patient demonstrated complete regression of all un-irradiated metastases, and near complete response of the primary lesion without additional therapy.

Conclusions: Metastatic RPS is typically managed with first-line chemotherapy, with objective response rates <50%. We present a case of inoperable metastatic RPS treated with palliative proton radiotherapy for rapidly progressive disease who had complete regression of non-irradiated metastases consistent with the abscopal effect. To our knowledge this is the first case report describing abscopal effects in inoperable metastatic RPS treated with proton radiation and is among the first case reports of an abscopal effect in a patient treated with proton therapy regardless of disease site. Further investigation is warranted regarding the benefit of proton radiation to primary tumors for inoperable metastatic RPS.

NBTXR3, a first-in-class radioenhancer hafnium oxide nanoparticle, plus radiotherapy versus radiotherapy alone in patients with locally advanced soft-tissue sarcoma (Act.In.Sarc): a multicentre, phase 2-3, randomised, controlled trial

BACKGROUND

Pathological complete response to preoperative treatment in adults with soft-tissue sarcoma can be achieved in only a few patients receiving radiotherapy. This phase 2-3 trial evaluated the safety and efficacy of the hafnium oxide (HfO₂) nanoparticle NBTXR3 activated by radiotherapy versus radiotherapy alone as a pre-operative treatment in patients with locally advanced soft-tissue sarcoma.

METHODS

Act.In.Sarc is a phase 2-3 randomised, multicentre, international trial. Adults (aged ≥18 years) with locally advanced soft-tissue sarcoma of the extremity or trunk wall, of any histological grade, and requiring preoperative radiotherapy were included. Patients had to have a WHO performance status of 0-2 and a life expectancy of at least 6 months. Patients were randomly assigned (1:1) by an interactive web response system to receive either NBTXR3 (volume corresponding to 10% of baseline tumour volume at a fixed concentration of 53·3 g/L) as a single intratumoural administration before preoperative external-beam radiotherapy (50 Gy in 25 fractions) or radiotherapy alone, followed by surgery. Randomisation was stratified by histological subtype (myxoid liposarcoma vs others). This was an open-label study. The primary endpoint was the proportion of patients with a pathological complete response, assessed by a central pathology review board following European Organisation for Research and Treatment of Cancer guidelines in the intention-to-treat population full analysis set. Safety analyses were done in all patients who received at least one puncture and injection of NBTXR3 or at least one dose of radiotherapy. This study is registered with ClinicalTrials.gov, number NCT02379845, and is ongoing for long-term follow-up, but recruitment is complete.

FINDINGS

Between March 3, 2015, and Nov 21, 2017, 180 eligible patients were enrolled and randomly assigned and 179 started treatment: 89 in the NBTXR3 plus radiotherapy group and 90 in the radiotherapy alone group. Two patients in the NBTXR3 group and one patient in the radiotherapy group were excluded from the efficacy analysis because they were subsequently discovered to be ineligible; thus, a total of 176 patients were analysed for the primary endpoint in the intention-to-treat full analysis set (87 in the NBTXR3 group and 89 in the radiotherapy alone group). A pathological complete response was noted in 14 (16%) of 87 patients in the NBTXR3 group and seven (8%) of 89 in the radiotherapy alone group (p=0·044). In both treatment groups, the most common grade 3-4 treatment-emergent adverse event was postoperative wound complication (eight [9%] of 89 patients in the NBTXR3 group and eight [9%] of 90 in the radiotherapy alone group). The most common grade 3-4 adverse events related to NBTXR3 administration were injection site pain (four [4%] of 89) and hypotension (four [4%]) and the most common grade 3-4 radiotherapy-related adverse event was radiation skin injury in both groups (five [6%] of 89 in the NBTXR3 group and four [4%] of 90 in the radiotherapy alone group). The most common treatment-emergent grade 3-4 adverse event related to NBTXR3 was hypotension (six [7%] of 89 patients). Serious adverse events were observed in 35 (39%) of 89 patients in the NBTXR3 group and 27 (30%) of 90 patients in the radiotherapy alone group. No treatment-related deaths occurred.

INTERPRETATION

This trial validates the mode of action of this new class of radioenhancer, which potentially opens a large field of clinical applications in soft-tissue sarcoma and possibly other cancers.

FUNDING

Nanobiotix SA.

Using Image-guided Intensity-modulated Radiotherapy on Patients With Head and Neck Soft-tissue Sarcoma

BACKGROUND

Image-guided intensity-modulated radiotherapy (IG-IMRT) is increasingly being used to treat patients with soft-tissue sarcoma (STS) of the head and neck. Although there is no comparison between IMRT and conventional radiation therapy (CRT) concerning their efficacy. In this analysis, we compared CRT and IMRT outcomes for head and neck STS.

PATIENTS AND METHODS

Sixty-seven patients who underwent radiotherapy between 1994 and 2017 were identified.

RESULTS

The median follow-up was 31 months. Of the 67 patients, 34% were treated with CRT technique and 66% with IG-IMRT. The locoregional relapse rate following IMRT was 21% versus 70% with CRT (p<0.001) and the 5-year locoregional control was 69% versus 28%, respectively (p=0.01). IG-IMRT was associated with non-significant, less acute, and chronic adverse events. In the multivariate analysis, a significant influence of radiation technique on locoregional control was confirmed (p=0.04).

CONCLUSION

IG-IMRT seems to be associated both with higher locoregional control as well as lower acute and chronic toxicities.

Treatment Outcomes and Prognostic Factors of Adult Sinonasal Sarcomas: A Single-Institution Case Series

BACKGROUND The purpose of this study was to investigate the treatment outcomes and evaluate the prognostic factors of adult sinonasal sarcomas. MATERIAL AND METHODS A retrospective review was performed on consecutive patients with adult sinonasal sarcomas treated in our institution from 2005 to 2016. The Kaplan-Meier method was used to evaluate local recurrence-free survival (LRFS), distant metastases-free survival (DMFS), and overall survival (OS). Univariate and multivariate analyses using Cox proportional hazard models were performed to determine the prognostic factors associated with survival outcomes. RESULTS A total of 49 patients were followed up for 6-122 months, with a median time of 36 months. The 5-year LRFS, DMFS, and OS rates of all patients were 68.3%, 62.8%, and 43.2%, respectively. The results of univariate analysis revealed that patients with an advanced stage of primary tumor and those who received incomplete surgical resection had worse LRFS (p=0.013; p=0.026). Patients with the histological type rhabdomyosarcoma (RMS) and existing regional lymph node metastasis had worse DMFS (p=0.000; p=0.001). The histological type RMS, advanced stage of primary tumor, existing regional lymph node metastasis, and receiving incomplete surgical resection had an unfavorable effect on OS (p=0.001; p=0.002; p=0.008; p=0.011). The results of multivariate analysis showed that histological type and degree of surgical resection were the independent prognostic factors for OS. CONCLUSIONS Our results suggest that the histological type RMS and receiving incomplete surgical resection are independent prognostic factors for worse OS.

Carbon ion radiotherapy for unresectable localized axial soft tissue sarcoma

Carbon ion radiotherapy is known for its high‐precision dose distribution and high biological effectiveness. We evaluated the results of carbon ion radiotherapy in 128 patients with unresectable localized axial soft tissue sarcoma at a single institution. The patients’ median age was 54 years, and the median follow‐up period was 49.4 (range 6.4‐146.4) months. The median tumor volume was 356 cm³. The 5‐year local control, overall survival, and disease‐free survival rates were 65%, 46%, and 39%, respectively. In the univariate analysis, tumor volume, local control, and incidences of metastases were significantly related to overall survival. In the multivariate analysis, tumor volume and local control were significantly related to overall survival. We did not find any factors related to local control. Five patients required surgical intervention because of adverse events in the bones. Carbon ion radiotherapy may be a treatment option for unresectable axial soft tissue sarcoma.

Feasibility of using stereotactic body radiation therapy for unresectable soft tissue tumors of the trunk

Purpose

To evaluate the feasibility of stereotactic body radiation therapy (SBRT) for unresectable soft tissue tumors of the trunk.

Materials and Methods

Between January 2002 and December 2008, 23 patients with 36 lesions of soft tissue tumors, which were located in the trunk and not suitable for resection, underwent SBRT. Among the 36 lesions, 31 were malignant and 5 were benign. The median tumor volume was 24 cm³ (range, 2.6–213 cm₃). SBRT doses ranged from 20 to 48 Gy in 1–5 fractions.

Results

With a median follow-up of 73 months, the overall survival (OS) and local control (LC) rates at 5 years were 39% and 52%, respectively. For malignant tumors, the OS and LC rates at 5 years were 28% and 47%, respectively. For benign tumors, the OS and LC rates at 5 years were 80% and 100%, respectively. There was no acute toxicity of grade ≥3. One case of grade 3 late skin toxicity was reported 10 months after SBRT.

Conclusion

SBRT may be an effective and safe treatment modality for the local control of unresectable soft tissue tumors of the trunk including tumors of a benign nature.

Salvage Carbon Ion Radiation Therapy for Locally Recurrent or Radiation-Induced Second Primary Sarcoma of the Head and Neck

Purpose: Salvage radiation therapy (RT) is a potentially curative treatment option for head and neck sarcomas (HNS) that did not respond to previous treatment(s). We report the first clinical experience of carbon ion radiotherapy (CIRT) for salvage treatment of locally recurrent (LR) or RT-induced secondary HNS after surgery and/or radiotherapy.

Methods and Materials: A retrospective analysis of the ongoing prospective data registries from the Shanghai Proton and Heavy Ion Center was conducted. Patients with LR-HNS who underwent surgery and/or RT and those with RT-induced second primary HNS were included. Acute and late toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 4.0 and the Radiation Therapy Oncology Group late radiation toxicity scoring system, respectively. The actuarial 12-month local progression-free and overall survival rates (LPFS and OS) were calculated using the Kaplan-Meier method.

Results: Between 10/2015 and 7/2017, 19 consecutive and non-selected patients with LR-HNS or RT-induced secondary HNS received definitive doses of CIRT delivered with pencil beam scanning technology for salvage. Six patients had locally recurrent soft-tissue sarcoma, and another 6 had chondrosarcoma. Among these 12 patients, 4 had received one prior course of RT. Seven additional patients had an RT-induced second primary soft tissue sarcoma (STS)/osteosarcoma after RT. The median time between the completion of initial treatment (either surgery only or surgery followed by adjuvant RT) and salvage CIRT was 30.6 months.

The median follow-up time was 13.1 (range 1.6-41.1) months. All patients except one (for re-irradiation) completed the planned CIRT for salvage. The median dose of salvage CIRT was 60 GyE. Three patients developed local progression, and another 3 developed distant metastasis after salvage CIRT. Deaths occurred (3 patients) only in patients with radiation-induced second primary sarcoma at the time of analysis. The actuarial 12-month LPFS, DMFS and OS rates were 74.6%, 82.6% and 86.5%, respectively.

Two patients irradiated for a second primary sarcoma had Grade 4 bleeding during CIRT, including one who experienced the rupture of an optic artery aneurysm unrelated to his disease or the salvage treatment. No patient had Grade 5 toxicity during treatment. Except for one patient who died of hemorrhage 3.5 months after the completion of CIRT, no moderate or severe late toxicities were observed.

Conclusions: With few observed acute and late toxicities, salvage CIRT can provide effective short-term tumor control. Further research, preferably in a prospective fashion, will be required to confirm the efficacy and safety of salvage CIRT in this patient population.