Bone Radiation-Induced Sarcomas: Outcomes Based on Histology and Surgical Treatment: A Systematic Review of the Literature.

BACKGROUND: Bone radiation-induced sarcomas (B-RIS) are secondary neoplasms with reportedly worse overall survival than de novo bone sarcoma. Treatment strategy for these neoplasms remains uncertain. Our systematic review sought to assess overall survival based on histology and surgical intervention. METHODS: A systemic review was conducted following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines and registered in PROSPERO (438415). Studies describing oncologic outcomes of patients with B-RIS in the appendicular and axial skeleton were included. The Strengthening the Reporting of Observational Studies in Epidemiology checklist was used for quality assessment. Survival analysis by histologic subtype and surgery type was performed in a subset of 234 patients from 11 articles with individualized data. A total of 20 articles with a total of 566 patients were included. The most frequent location was the pelvis (27.7%), and the main histological types were osteosarcoma (69.4%), undifferentiated pleomorphic sarcoma (14.1%), and fibrosarcoma (9.2%). Limb-salvage and amputation were performed in 68.5% and 31.5% of cases, respectively. RESULTS: Local recurrence was 13%, without difference between limb-salvage surgery and amputation (p = 0.51). The metastasis rate was 42.3%. Five-year OS was 43.7% (95% confidence interval [CI], 33.3%-53.5%) for osteosarcoma, 31.5% (95% CI, 11.3%-54.2%) for UPS, and 28.1% (95% CI, 10.6%-48.8%) for fibrosarcoma. Five-year OS was 49.2% (95% CI, 35.3%-61.6%) for limb-salvage and 46.9% (95% CI, 29.1%-62.9%) for amputation. There was no difference in 5-year OS between histologic subtypes (p = 0.18) or treatment type (p = 0.86). CONCLUSION: B-RIS demonstrated poor OS at 5 years after initial management regardless of histology. Limb-salvage surgery was not associated with lower 5-year OS compared with amputation. Future studies should compare both groups while controlling for confounders. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.

Enhancing radiotherapy response via intratumoral injection of a TLR9 agonist in autochthonous murine sarcomas.

Radiation therapy (RT) is frequently used to treat cancers, including soft-tissue sarcomas. Prior studies established that the toll-like receptor 9 (TLR9) agonist cytosine-phosphate-guanine oligodeoxynucleotide (CpG) enhances the response to RT in transplanted tumors, but the mechanisms of this enhancement remain unclear. Here, we used CRISPR/Cas9 and the chemical carcinogen 3-methylcholanthrene (MCA) to generate autochthonous soft-tissue sarcomas with high tumor mutation burden. Treatment with a single fraction of 20 Gy RT and 2 doses of CpG significantly enhanced tumor response, which was abrogated by genetic or immunodepletion of CD8+ T cells. To characterize the immune response to CpG+RT, we performed bulk RNA-Seq, single-cell RNA-Seq, and mass cytometry. Sarcomas treated with 20 Gy and CpG demonstrated increased CD8 T cells expressing markers associated with activation and proliferation, such as Granzyme B, Ki-67, and IFN-γ. CpG+RT also upregulated antigen presentation pathways on myeloid cells. Furthermore, in sarcomas treated with CpG+RT, TCR clonality analysis suggests an increase in clonal T cell dominance. Collectively, these findings demonstrate that CpG+RT significantly delays tumor growth in a CD8 T cell-dependent manner. These results provide a strong rationale for clinical trials evaluating CpG or other TLR9 agonists with RT in patients with soft-tissue sarcoma.

Predicting radiotherapy response, Toxicities and quality-of-life related functional outcomes in soft tissue sarcoma of the extremities (PredicT) using dose-volume constraints development: a study protocol.

INTRODUCTION: Radiotherapy improves local tumour control in patients with soft tissue sarcoma of the extremities (STSE) but it also increases the probability of long-term toxicities such as tissue fibrosis, joint stiffness and lymphoedema. The use of radiation dose and volume thresholds, called dose constraints, may potentially reduce the development of toxicities in STSE. The aim of this study is to determine predictors of radiotherapy-related side effects for STSE. METHODS AND ANALYSIS: Predicting radiotherapy response, Toxicities and quality-of-life related functional outcomes in soft tissue sarcoma of the extremities (PredicT) is a multicentre observational study comprising two cohorts (PredicT A and B). PredicT A, a retrospective analysis of the UK VorteX (NCT00423618) and IMRiS clinical trials (NCT02520128), is aimed at deriving a statistical model for development of dose-volume constraints. This model will use receiving operator characteristics and multivariate analysis to predict radiotherapy side effects and patient-reported outcomes. PredicT B, a prospective cohort study of 150 patients with STSE, is aimed at testing the validity of those dose-volume constraints. PredicT B is open and planned to complete recruitment by September 2024. ETHICS AND DISSEMINATION: PredicT B has received ethical approval from North West - Liverpool Central Research Ethics Committee (20/NW/0267). Participants gave informed consent to participate in the study before taking part. We will disseminate our findings via publications, presentations, national and international conference meetings and engage with local charities. TRIAL REGISTRATION NUMBER: NCT05978024.

Monte Carlo dosimetric analyses on the use of90Y-IsoPet intratumoral therapy in canine subjects.

Objective.To investigate different dosimetric aspects of90Y-IsoPet™ intratumoral therapy in canine soft tissue sarcomas, model the spatial spread of the gel post-injection, evaluate absorbed dose to clinical target volumes, and assess dose distributions and treatment efficacy.Approach.Six canine cases treated with90Y-IsoPet™ for soft tissue sarcoma at the Veterinary Health Center, University of Missouri are analyzed in this retrospective study. The dogs received intratumoral IsoPet™ injections, following a grid pattern to achieve a near-uniform dose distribution in the clinical target volume. Two dosimetry methods were performed retrospectively using the Monte Carlo toolkit OpenTOPAS: imaging-based dosimetry obtained from post-injection PET/CT scans, and stylized phantom-based dosimetry modeled from the planned injection points to the gross tumor volume. For the latter, a Gaussian parameter with variable sigma was introduced to reflect the spatial spread of IsoPet™. The two methods were compared using dose-volume histograms (DVHs) and dose homogeneity, allowing an approximation of the closest sigma for the spatial spread of the gel post-injection. In addition, we compared Monte Carlo-based dosimetry with voxel S-value (VSV)-based dosimetry to investigate the dosimetric differences.Main results.Imaging-based dosimetry showed differences between Monte Carlo and VSV calculations in tumor high-density areas with higher self-absorption. Stylized phantom-based dosimetry indicated a more homogeneous target dose with increasing sigma. The sigma approximation of the90Y-IsoPet™ post-injection gel spread resulted in a median sigma of approximately 0.44 mm across all cases to reproduce the dose heterogeneity observed in Monte Carlo calculations.Significance.The results indicate that dose modeling based on planned injection points can serve as a first-order approximation for the delivered dose in90Y-IsoPet™ therapy for canine soft tissue sarcomas. The dosimetry evaluation highlights the non-uniformity of absorbed doses despite the gel spread, emphasizing the importance of considering tumor dose heterogeneity in treatment evaluation. Our findings suggest that using Monte Carlo for dose calculation seems more suitable for this type of tumor where high-density areas might play an important role in dosimetry.

Novel MRI scoring system to assess osseous malignancy in soft tissue sarcoma patients following radiotherapy.

PURPOSE: Radiation induced changes in bone such as radiation osteitis are commonly identified on magnetic resonance imaging (MRI) in patients who receive radiotherapy for soft tissue sarcoma (STS) management. This study proposes a novel MRI scoring system to assess osseous lesions and predict potential for malignancy based on MRI score in STS patients who received radiotherapy. METHODS: The MRI score consisted of 3 parameters: morphology, signal intensity, and progression. Interobserver reliability between MRI scores were analyzed with Cohen's kappa coefficient. Receiver operating curve (ROC) analysis was performed to determine a predictive MRI score for malignancy. RESULTS: 156 MRI's from 30 STS patients who received radiotherapy were retrospectively reviewed. Two (6.7 %) patients developed regional osseous metastasis identified on MRI. The kappa coefficient of the scoring system was 0.785 demonstrating substantial interobserver agreement (p < 0.001). ROC analysis demonstrated that the optimal cut-off value for malignant lesion on MRI was 5.5 (area under the curve 0.998; p < 0.001). CONCLUSIONS: This novel MRI scoring system recommends lesions with a score of six and above to be biopsied to distinguish if malignancy is present. We believe this scoring system can be utilized by multidisciplinary care teams to guide clinical recommendations for patients with STS and MRI findings concerning for malignancy versus radiation induced changes.

Outcomes of non-angiosarcoma radiation-associated soft tissue sarcomas of the chest.

BACKGROUND: Radiation-associated soft tissue sarcomas (RA-STS) are rare complications of patients receiving radiation therapy (RT) and are generally associated with a poor prognosis. Most of the literature surrounding RA-STS of the chest is centered on angiosarcoma. Therefore, we aim to document the management and outcome of patients with non-angiosarcoma RA-STS of the chest. METHODS: We reviewed 17 patients (all female, median age 65 years) diagnosed with RA-STS. The most common primary malignancy was breast carcinoma (n = 15), with a median RT dose of 57.9 Gy. All patients underwent surgical resection; five patients (29%) received radiotherapy; and five patients (29%) received peri-operative chemotherapy. RESULTS: The 5-year local recurrence and metastatic-free survival were 61% and 60%, while the 5-year disease-specific survival was 53%. Local recurrence was associated with death due to disease (HR 9.06, p = 0.01). Complications occurred in nine of patients, most commonly due to a wound complication (n = 7). At the most recent follow-up, the median Musculoskeletal Tumor Society Score was 63%. CONCLUSION: RA-STS involving the chest wall are aggressive tumors with a high risk of local relapse and death due to disease. Local recurrence was associated with death due to disease; as such, we recommend aggressive surgical management with evaluation for adjuvant therapies.

[Radiation-induced sarcoma in patients with nasopharyngeal carcinoma: a single-institution retrospective study].

Objective:To analyze the clinical features, treatment methods and prognosis of radiation-induced sarcoma（RIS） of the head and neck after radiotherapy for nasopharyngeal carcinoma（NPC）, and explore its treatment strategies. Methods:A retrospective analysis was conducted on RIS patients after radiotherapy for NPC in the People's Hospital of Guangxi Zhuang Autonomous Region from January 2013 to October 2022. The time of onset, lesion location, pathological subtypes, imaging features and treatment outcomes were described, and the median survival time was statistically analyzed through follow-up. Results:This study included 10 patients with an interval of 2-27 years between NPC and RIS. The nasopharynx was the more common site of RIS, and osteosarcoma was the main pathological type. The median overall survival was 18 months. The median survival was 40 months in the surgery combined with the chemotherapy group, and 12 months in the surgery alone group. The 1-and 2-year cumulative survival rates were 48% and 36%, respectively. Prognostic analysis showed that gender, age of onset, time of sarcoma onset after radiotherapy and treatment methods might not be influencing factors for prognosis, and osteosarcomas presented a poorer prognosis than other pathological types. Conclusion:RIS is one of the most severe long-term adverse effects in patients with NPC. The prognosis of RIS is poor, and complete surgical resection of the tumor can improve patient survival rates. In cases where complete surgical resection is challenging, radiotherapy or chemotherapy may offer some improvement in tumor control.

Outcomes for Patients With Head and Neck Sarcoma Treated Curatively With Radiation Therapy and Surgery.

PURPOSE: Soft tissue sarcomas (STSs) of the head and neck (H&N) are rare malignancies that are challenging to manage. We sought to describe the outcomes of patients treated with curative intent using combined surgery and radiation therapy (RT) for H&N STS. METHODS AND MATERIALS: We performed a single-institution retrospective review of patients with nonmetastatic STS of the H&N who were treated from 1968 to 2020. The Kaplan-Meier method was used to estimate disease-specific survival (DSS) and local control (LC). Multivariable analyses (MVAs) were conducted using Cox proportional hazards model. RESULTS: One hundred ninety-two patients had a median follow-up of 82 months. Tumors arose in the neck (n = 50, 26%), paranasal sinuses (n = 36, 19%), or face (n = 23, 12%). Most patients were treated with postoperative RT (n = 134, 70%). Postoperative RT doses were higher (median, 60 Gy; preoperative dose, 50 Gy; P < .001). Treatment sequence was not associated with LC (preoperative RT, 78% [63%-88%]; postoperative RT, 75% [66%-82%]; P = .48). On MVA, positive/uncertain margin was the only variable associated with LC (hazard ratio [HR], 2.54; 95% CI, 1.34-4.82; P = .004). LC was significant on MVA (HR, 4.48; 95% CI, 2.62-7.67; P < .001) for DSS. Patients who received postoperative RT were less likely to experience a major wound complication (7.5% vs 22.4%; HR, 0.28; 95% CI, 0.11-0.68; P = .005). There was no difference in the rate of late toxicities between patients who received preoperative or postoperative RT. CONCLUSIONS: H&N STS continues to have relatively poorer LC than STS of the trunk or extremities. We found LC to be associated with DSS. Timing of RT did not impact oncologic or long-term toxicity outcomes; however, preoperative RT did increase the chance of developing a major wound complication.

First Experience of Radionuclide Therapy With 177Lu-FAPI-2286 in a Patient With Metastatic Mediastinal Sarcoma.

ABSTRACT: Fibroblast activation protein (FAP) is a new promising molecular target for theragnostic approach. FAP inhibitors (FAPIs) labeled with 177Lu could be potentially a therapeutic radiopharmaceutical. Here, we presented the experience of 4 cycles of 177Lu-FAPI in a 67-year-old man with an unresectable mediastinal sarcoma.

Prospective phase II trial of preoperative hypofractionated proton therapy for extremity and truncal soft tissue sarcoma: the PRONTO study rationale and design.

BACKGROUND: Oncologic surgical resection is the standard of care for extremity and truncal soft tissue sarcoma (STS), often accompanied by the addition of pre- or postoperative radiation therapy (RT). Preoperative RT may decrease the risk of joint stiffness and fibrosis at the cost of higher rates of wound complications. Hypofractionated, preoperative RT has been shown to provide acceptable outcomes in prospective trials. Proton beam therapy (PBT) provides the means to decrease dose to surrounding organs at risk, such as the skin, bone, soft tissues, and adjacent joint(s), and has not yet been studied in patients with extremity and truncal sarcoma. METHODS: Our study titled "PROspective phase II trial of preoperative hypofractionated protoN therapy for extremity and Truncal soft tissue sarcOma (PRONTO)" is a non-randomized, prospective phase II trial evaluating the safety and efficacy of preoperative, hypofractionated PBT for patients with STS of the extremity and trunk planned for surgical resection. Adult patients with Eastern Cooperative Group Performance Status ≤ 2 with resectable extremity and truncal STS will be included, with the aim to accrue 40 patients. Treatment will consist of 30 Gy radiobiological equivalent of PBT in 5 fractions delivered every other day, followed by surgical resection 2-12 weeks later. The primary outcome is rate of major wound complications as defined according to the National Cancer Institute of Canada Sarcoma2 (NCIC-SR2) Multicenter Trial. Secondary objectives include rate of late grade ≥ 2 toxicity, local recurrence-free survival and distant metastasis-free survival at 1- and 2-years, functional outcomes, quality of life, and pathologic response. DISCUSSION: PRONTO represents the first trial evaluating the use of hypofractionated PBT for STS. We aim to prove the safety and efficacy of this approach and to compare our results to historical outcomes established by previous trials. Given the low number of proton centers and limited availability, the short course of PBT may provide the opportunity to treat patients who would otherwise be limited when treating with daily RT over several weeks. We hope that this trial will lead to increased referral patterns, offer benefits towards patient convenience and clinic workflow efficiency, and provide evidence supporting the use of PBT in this setting. TRIAL REGISTRATION: NCT05917301 (registered 23/6/2023).

Radiation-induced Sarcoma of the Prostate After Treatment for Rhabdomyosarcoma.

Rhabdomyosarcoma (RMS) is among the most common pediatric solid malignancies. Fusion-negative, embryonal RMS is the predominant histology among prostate and bladder lesions. Management strategies depend on the clinical stage and risk group. Although the optimal strategy continues to evolve, the field has transitioned from radical upfront resection to organ preservation strategies with multi-modal therapy, including chemotherapy, radiation, and surgery. Survivors frequently develop late complications, including impaired fertility and sexual function, bladder dysfunction, and secondary malignancies. Our case describes an 11-year-old male who developed a radiation-induced prostatic sarcoma. We present a novel surgical technique and highlight the importance of multidisciplinary care.

Meta-Analysis of 5-Fraction Preoperative Radiotherapy for Soft Tissue Sarcoma.

OBJECTIVES: Studies investigating preoperative 5-fraction radiation therapy (RT) for soft tissue sarcoma (STS) are limited. We performed a meta-analysis to determine the efficacy and safety of this treatment paradigm. METHODS: This study-level meta-analysis was conducted using Bayesian methods. Statistical estimation for risk of outcome rates was conducted by posterior mean and 95% highest posterior density (HPD) intervals. Studies with 2-year local control (LC) and description of major wound complications (MWC) per the CAN-NCIC-SR2 study were included and served as the primary endpoints. Secondary endpoints included rates of acute and late toxicity. A total of 10 studies were identified and 7 met the inclusion criteria. Subgroup analyses were performed for ≥30 Gy vs <30 Gy. RESULTS: A total of 209 patients from 7 studies were included. Five studies used ≥30 Gy (n=144), and 2 studies <30 Gy (n=64). Median follow-up was 29 months (range: 21 to 57 mo). Primary tumor location was lower extremity in 68% and upper extremity in 22%. Most tumors were intermediate or high grade (95%, 160/169), and 50% (79/158) were >10 cm. The two-year LC for the entire cohort was 96.9%, and the rate of MWC was 30.6%. There was a trend toward improved LC with ≥ 30 Gy (95% HPD: 0.95 to 0.99 vs 0.84 to 0.99). There was no difference in MWC (95% HPD: 0.18 to 0.42 vs 0.17 to 0.55) or late toxicity between the groups. CONCLUSIONS: Preoperative 5-fraction RT for STS demonstrates excellent 2-year LC with MWC and toxicity similar to standard fractionation preoperative RT. Multi-institutional trials with a universal RT protocol are warranted.

Development and benchmarking of a Deep Learning-based MRI-guided gross tumor segmentation algorithm for Radiomics analyses in extremity soft tissue sarcomas.

BACKGROUND: Volume of interest (VOI) segmentation is a crucial step for Radiomics analyses and radiotherapy (RT) treatment planning. Because it can be time-consuming and subject to inter-observer variability, we developed and tested a Deep Learning-based automatic segmentation (DLBAS) algorithm to reproducibly predict the primary gross tumor as VOI for Radiomics analyses in extremity soft tissue sarcomas (STS). METHODS: A DLBAS algorithm was trained on a cohort of 157 patients and externally tested on an independent cohort of 87 patients using contrast-enhanced MRI. Manual tumor delineations by a radiation oncologist served as ground truths (GTs). A benchmark study with 20 cases from the test cohort compared the DLBAS predictions against manual VOI segmentations of two residents (ERs) and clinical delineations of two radiation oncologists (ROs). The ROs rated DLBAS predictions regarding their direct applicability. RESULTS: The DLBAS achieved a median dice similarity coefficient (DSC) of 0.88 against the GTs in the entire test cohort (interquartile range (IQR): 0.11) and a median DSC of 0.89 (IQR 0.07) and 0.82 (IQR 0.10) in comparison to ERs and ROs, respectively. Radiomics feature stability was high with a median intraclass correlation coefficient of 0.97, 0.95 and 0.94 for GTs, ERs, and ROs, respectively. DLBAS predictions were deemed clinically suitable by the two ROs in 35% and 20% of cases, respectively. CONCLUSION: The results demonstrate that the DLBAS algorithm provides reproducible VOI predictions for radiomics feature extraction. Variability remains regarding direct clinical applicability of predictions for RT treatment planning.

Targeting glutamine metabolism improves sarcoma response to radiation therapy in vivo.

Diverse tumor metabolic phenotypes are influenced by the environment and genetic lesions. Whether these phenotypes extend to rhabdomyosarcoma (RMS) and how they might be leveraged to design new therapeutic approaches remains an open question. Thus, we utilized a Pax7Cre-ER-T2/+; NrasLSL-G12D/+; p53fl/fl (P7NP) murine model of sarcoma with mutations that most frequently occur in human embryonal RMS. To study metabolism, we infuse 13C-labeled glucose or glutamine into mice with sarcomas and show that sarcomas consume more glucose and glutamine than healthy muscle tissue. However, we reveal a marked shift from glucose consumption to glutamine metabolism after radiation therapy (RT). In addition, we show that inhibiting glutamine, either through genetic deletion of glutaminase (Gls1) or through pharmacological inhibition of glutaminase, leads to significant radiosensitization in vivo. This causes a significant increase in overall survival for mice with Gls1-deficient compared to Gls1-proficient sarcomas. Finally, Gls1-deficient sarcomas post-RT elevate levels of proteins involved in natural killer cell and interferon alpha/gamma responses, suggesting a possible role of innate immunity in the radiosensitization of Gls1-deficient sarcomas. Thus, our results indicate that glutamine contributes to radiation response in a mouse model of RMS.