Immunotherapy in soft tissue sarcoma: current evidence and future perspectives in a variegated family of different tumour

Spatial distribution of tumour immune infiltrate predicts outcomes of patients with high-risk soft tissue sarcomas after neoadjuvant chemotherapy

BACKGROUND

Anthracycline-based neoadjuvant chemotherapy (NAC) may modify tumour immune infiltrate. This study characterized immune infiltrate spatial distribution after NAC in primary high-risk soft tissue sarcomas (STS) and investigate association with prognosis.

METHODS

The ISG-STS 1001 trial randomized STS patients to anthracycline plus ifosfamide (AI) or a histology-tailored (HT) NAC. Four areas of tumour specimens were sampled: the area showing the highest lymphocyte infiltrate (HI) at H&E; the area with lack of post-treatment changes (highest grade, HG); the area with post-treatment changes (lowest grade, LG); and the tumour edge (TE). CD3, CD8, PD-1, CD20, FOXP3, and CD163 were analyzed at immunohistochemistry and digital pathology. A machine learning method was used to generate sarcoma immune index scores (SIS) that predict patient disease-free and overall survival (DFS and OS).

FINDINGS

Tumour infiltrating lymphocytes and PD-1+ cells together with CD163+ cells were more represented in STS histologies with complex compared to simple karyotype, while CD20+ B-cells were detected in both these histology groups. PD-1+ cells exerted a negative prognostic value irrespectively of their spatial distribution. Enrichment in CD20+ B-cells at HI and TE areas was associated with better patient outcomes. We generated a prognostic SIS for each tumour area, having the HI-SIS the best performance. Such prognostic value was driven by treatment with AI.

INTERPRETATION

The different spatial distribution of immune populations and their different association with prognosis support NAC as a modifier of tumour immune infiltrate in STS.

FUNDING

Pharmamar; Italian Ministry of Health [RF-2019-12370923; GR-2016-02362609]; 5 × 1000 Funds-2016, Italian Ministry of Health; AIRC Grant [ID#28546].

Long Duration Pembrolizumab for Metastatic Undifferentiated Pleomorphic Soft Tissue Sarcoma With Multimodality Therapy

Patients with undifferentiated pleomorphic sarcoma (UPS) of soft tissue have responsiveness to immunotherapy treatment. Since few patients with soft tissue sarcoma respond to immunotherapy, guidelines for its management are lacking. Specifically, the optimal duration of immunotherapy is unclear. This report is unique owing to the probable longest reporting of successful continuous immunotherapy for metastatic UPS over 6.5 years and 109 cycles. Here a patient who developed metastatic UPS is presented. The patient required systemic therapy for metastatic sarcoma, eventually with immunotherapy. A prolonged treatment over many years is elaborated. A robust response was seen but occasionally augmented by adding external beam radiation therapy (XRT). Treatment was tolerated without adverse effects. A brief review of current treatment practice and known risks of prolonged immunotherapy is presented. For similar patients, a lengthy treatment course, beyond that utilized for other malignancies, can be considered. This is likely to be safe if it is tolerated and without early adverse effects. Other treatment modalities such as palliative surgery and XRT are described which may also be required for management of mixed responses.

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.

Combining nanoparticle albumin-bound paclitaxel with camrelizumab in advanced soft tissue sarcoma: activity, safety, and future perspectives

Background: It is still uncertain whether Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) and programmed cell death protein 1 (PD-1) inhibitor have synergistic effects on metastatic soft tissue sarcomas (STSs). The purpose of this study was to evaluate the safety and activity of nab-paclitaxel plus camrelizumab (a PD-1 inhibitor) in patients with advanced STS who had previously failed chemotherapy. Methods: In this single-center, open-label, single-arm phase II clinical trial, patients with advanced (unresectable or metastatic) STS who had previously failed chemotherapy received up to six cycles of nab-paclitaxel plus camrelizumab, whereas camrelizumab treatment was continued for up to 1 year. The median progression-free survival (PFS), objective response rate (ORR) and safety were collected and evaluated. Results: This trial included 40 patients (28 men and 12 women). The overall ORR was 22.5%, and the median PFS was 1.65 months (95% confidence interval [CI], 1.3-2.0 months). Patients with epithelioid sarcoma demonstrated a longer PFS compared with those with other histological subtypes (2.3 months vs. 1.5 months, respectively); however, this difference was not significant. Patients who had received only one line of previous chemotherapy had a significantly longer PFS compared with those who had undergone two or more lines of previous chemotherapy (2.8 months vs. 1.3 months, respectively, p = 0.046). In terms of safety, the toxicity of this combination therapy is mild and no serious adverse events have occurred. Conclusion: Nab-paclitaxel plus camrelizumab exhibited modest activity and mild toxicity in treating epithelioid sarcoma, angiosarcoma, and fibrosarcoma. The overall effectiveness of this treatment regimen for advanced STS is relatively low. Further research on combining nab-paclitaxel with effective drugs, including chemotherapy and targeted agents, for these specific STS subtypes is needed.

Targeting EZH2 in SMARCB1-deficient sarcomas: Advances and opportunities to potentiate the efficacy of EZH2 inhibitors

Soft tissue sarcomas (STSs) are rare mesechymal malignancies characterized by distintive molecular, histological and clinical features. Many STSs are considered as predominatly epigenetic diseases due to underlying chromatin deregulation. Discovery of deregulated functional antagonism between the chromatin remodeling BRG1/BRM-associated (BAFs) and the histone modifying Polycomb repressor complexes (PRCs) has provided novel actionable targets. In epithelioid sarcoma (ES), extracranial, extrarenal malignant rhabdoid tumors (eMRTs) and synovial sarcoma (SS), the total or partial loss of the BAF core subunit SMARCB1, driven by different alterations, is associated with PRC2 deregulation and dependency on its enzymatic subunit, EZH2. In these SMARCB1-deficient STSs, aberrant EZH2 expression and/or activity emerged as a druggable vulnerability. Although preclinical investigation supported EZH2 targeting as a promising therapeutic option, clinical studies demonstrated a variable response to EZH2 inhibitors. Actually, whereas the clinical benefit recorded in ES patients prompted the FDA approval of the EZH2 inhibitor tazemetostat, the modest and sporadic responses observed in eMRT and SS patients highlighted the need to deepen mechanistic as well as pharmacological investigations to improve drug effectiveness. We summarize the current knowledge of different mechanisms driving SMARCB1 deficiency and EZH2 deregulation in ES, eMRT and SS along with preclinical and clinical studies of EZH2-targeting agents. Possible implication of the PRC2- and enzymatic-independent functions of EZH2 and of its homolog, EZH1, in the response to anti-EZH2 agents will be discussed together with combinatorial strategies under investigation to improve the efficacy of EZH2 targeting in these tumors.

Immunotherapy Plus Radiotherapy for the Treatment of Sarcomas: Is There a Potential for Synergism?

Soft tissue sarcoma (STS) is a highly heterogeneous malignant tumor derived from mesenchymal tissue. Advanced STS has a poor response to the current anti-cancer therapeutic options, with a median overall survival of less than two years. Thus, new and more effective treatment methods for STS are needed. Increasing evidence has shown that immunotherapy and radiotherapy have synergistic therapeutic effects against malignant tumors. In addition, immunoradiotherapy has yielded positive results in clinical trials for various cancers. In this review, we discuss the synergistic mechanism of immunoradiotherapy in cancer treatment and the application of this combined regimen for the treatment of several cancers. In addition, we summarize the existing evidence on the use of immunoradiotherapy for the treatment of STS and the relevant clinical trials that are currently ongoing. Furthermore, we identify challenges in the use of immunoradiotherapy for the treatment of sarcomas and propose methods and precautions for overcoming these challenges. Lastly, we propose clinical research strategies and future research directions to help in the research and treatment of STS.

Histology-tailored multidisciplinary management of primary retroperitoneal sarcomas

Until recently, the recommendation for primary retroperitoneal sarcomas (RPS) was to perform a complete en-bloc gross excision, (neo) adjuvant treatments being options which were not validated by randomized studies, with a large discrepancy of use between centers. The heterogeneity of RPS, with their different biological behaviour, renders a homogenous therapeutic and surgical approach probably inappropriate. Recent studies, both surgical and dedicated to adjuvant treatments, allow refining these recommendations. This review summarizes recent advances and directions.

The Landscape of Immunotherapy for Retroperitoneal Sarcoma

Significant multidisciplinary scientific effort has been undertaken to understand the heterogeneous family of neoplasms that comprise soft tissue sarcomas. Within this family of neoplasms, outcomes for retroperitoneal sarcomas (RPS) are currently limited given a lack of effective therapies. In this review, we focus on immunotherapy and its relationship with the common RPS histologic subtypes. Although initial outcomes for RPS patients with immune checkpoint inhibition alone have been somewhat disappointing, subsequent analyses on histologies, the tumor microenvironment, sarcoma immune class, tumor infiltrating lymphocytes and genetic analysis for tumor mutational burden have yielded insight into the interplay between sarcomas and immunotherapy. Such approaches have all provided critical insight into the environment and characterization of these tumors, with targets for potential immunotherapy in future clinical trials. With this insight, molecularly tailored combination treatments for improving response rates and oncologic outcomes for RPS are promising.

Cuproptosis-associated lncRNAs discern prognosis and immune microenvironment in sarcoma victims

Cuproptosis is a fresh form of the copper-elesclomol-triggered, mitochondrial tricarboxylic acid (TCA) dependent cell death. Yet, the subsumed mechanism of cuproptosis-associated lncRNAs in carcinoma is not wholly clarified. Here, We appraised 580 cuproptosis-associated lncRNAs in sarcoma and thereafter construed a module composing of 6 cuproptosis lncRNAs, entitled CuLncScore, utilizing a machine learning methodology. It could outstandingly discern the prognosis of patients in parallel with discriminating tumor immune microenvironment traits. Moreover, we simulate the classification system of cuproptosis lncRNAs by unsupervised learning method to facilitate differentiation of clinical denouement and immunotherapy modality options. Notably, Our Taizhou cohort validated the stability of CuLncScore and the classification system. Taking a step further, we checked these 6 cuproptosis lncRNAs by Quantitative real-time polymerase chain reaction (qRT-PCR) to ascertain their authenticity. All told, our investigations highlight that cuproptosis lncRNAs are involved in various components of sarcoma and assist in the formation of the tumor immune microenvironment. These results provide partial insights to further comprehend the molecular mechanisms of cuproptosis lncRNAs in sarcoma and could be helpful for the development of personalized therapeutic strategies targeting cuproptosis or cuproptosis lncRNAs.