Luc M. Berclaz

Leiomyosarcoma is an aggressive soft tissue sarcoma that metastasizes preferentially to lung and liver. Because matched primary and metastatic specimens are rarely available, the cellular changes that accompany metastatic progression remain poorly defined. Here we combined single-nucleus RNA sequencing of archival FFPE tissue from four matched primary-metastasis pairs (two lung, two liver metastases; 48,941 nuclei) with imaging-based spatial transcriptomics of an extended tissue microarray cohort of 21 patients (69 cores, 313,218 cells). Malignant cells, not assignable from transcriptomic references alone, were defined by inferred copy number profiles that were concordant with matched DNA methylation arrays and confirmed the clonal origin of each metastasis. Malignant metaprograms were organ-associated, with a stress- and hypoxia-associated program enriched in lung metastases and a proliferative, matrix-remodeling program enriched in liver metastases. Antigen-presenting cancer-associated fibroblasts (apCAFs) were enriched in metastases relative to matched primaries. This shift was reproduced in the spatial cohort (p = 0.001), where apCAFs formed a discrete band at the tumor-organ interface between malignant cells and adjacent parenchyma, whereas they were sparse and randomly distributed in primary tumors. Spatial transcriptomics further resolved the malignant compartment into three histomolecular phenotypes: (i) smooth-muscle-like with myxoid features, (ii) GPNMB⁺ with anaplastic features, and (iii) PDGFRB⁺ with vessel-rich stroma, each with a concordant immunohistochemical (α-SMA, GPNMB, PDGFRB) and morphological correlate. Together, our data provide a matched primary-metastasis reference for leiomyosarcoma, identify apCAFs as a spatially organized, metastasis-associated stromal population, and delineate histomolecular phenotypes recognizable by routine immunohistochemistry, including a GPNMB⁺ phenotype potentially amenable to GPNMB-directed therapies.

Evidence guiding the optimal sequencing of later-line systemic therapy in advanced soft tissue sarcoma (STS) remains limited. The aim of this study was to identify prognostic factors for overall survival (OS) beyond second-line treatment and to explore therapy sequencing in routine clinical practice. A total of 90 patients with advanced STS receiving third-line or later systemic therapy were retrospectively analyzed. Extreme gradient boosting (XGBoost) was used to identify clinical predictors of 1-year OS. The most influential variables were subsequently evaluated in multivariable Cox models for OS from the start of third- and fourth-line therapy. Sequencing analyses compared OS according to the line of administration of commonly used later-line agents. In the third-line cohort (n = 88), inferior OS was independently associated with progression on second-line therapy (hazard ratio [HR] 2.31, p = 0.005). In contrast, lipo-/leiomyosarcoma histology was associated with improved survival (HR 0.37, p = 0.002), as was a time to progression ≥ 12 months on first-line therapy (HR 0.43, p = 0.007). Findings were largely consistent in the fourth-line cohort (n = 57). Sequencing analyses suggested sustained activity of trabectedin in later lines (p = 0.023), greater benefit of earlier pazopanib use (p = 0.022), and no significant impact of treatment line for gemcitabine + docetaxel combination therapy (p = 0.12). Machine learning-guided variable selection identified clinically relevant predictors of survival in later-line STS. Prior treatment response and histology strongly influence outcomes, and exploratory sequencing analyses suggest differential timing effects across systemic therapy agents.

Background: Large Language Models (LLMs) have demonstrated expert-level performance across many medical domains, suggesting potential utility in clinical practice. However, their reliability in the highly specialized domain of moderate hyperthermia (HT) remains unknown. We therefore evaluated the performance of three modern LLMs in answering HT-related questions. Methods: We conducted an evaluation study by posing 40 open-ended questions—22 clinical and 18 physics-related—to three modern LLMs (DeepSeek-V3, Llama-3.3-70B-Instruct, and GPT-4o). Responses were blinded, randomized, and evaluated by 19 international experts with either a clinical or physics background for quality (5-point Likert scale: 1=very bad, 2=bad, 3=acceptable, 4=good to 5=very good) and for potential harmfulness in clinical decision-making. Results: A total of 1144 quality evaluation responses were collected. Overall reported mean quality scores were similar across models, with DeepSeek scoring 3.26, Llama 3.18, and GPT-4o 3.07, corresponding to an “acceptable” rating. Across expert evaluations, responses were considered potentially harmful in 17.8% of cases for DeepSeek, 19.3% for Llama, and 15.3% for GPT-4o. Notably, despite “acceptable” mean scores, approximately 25% of responses were rated “bad” to “very bad,” and potentially harmful answers occurred in ∼15–19% of evaluations, indicating a non-trivial risk if used without domain expertise. Conclusion: Our findings indicate that the performance of LLMs in HT in versions available at the time of investigation is only partially satisfactory. The proportion of poor-quality responses is too high and may lead non-domain experts to misinterpret the available clinical evidence and draw inappropriate clinical conclusions.

Purpose: High-dose ifosfamide (HD-IFO) remains an effective regimen for advanced bone and soft tissue sarcomas, but predictors of long-term benefit are poorly defined. This study evaluated clinical outcomes and prognostic factors using machine learning-assisted modeling in sarcoma patients treated with HD-IFO at a high-volume academic center. Methods: We retrospectively analyzed 26 patients with histologically confirmed bone or soft tissue sarcoma who received HD-IFO (≥ 12 g/m ² per cycle) between 2015 and 2025. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan–Meier method and compared across RECIST response categories using log-rank testing. Prognostic factors were identified using Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression with leave-one-out cross-validation. The top three variables were entered into multivariable logistic regression to estimate odds ratios (ORs) for OS > 24 months. Results: Median PFS and OS from start of HD-IFO was 6.6 months (95% CI 4.4–9.8) and 24.7 months (95% CI, 14.7–34.2), respectively. Patients with progressive disease (PD) had significantly shorter OS than those with partial response (PR; p = 0.0047) or stable disease (SD; p = 0.0485). LASSO identified intervention prior to progression, prior tumor control ≥ 12 months, and absence of metastases as the strongest predictors for OS > 24 months. In multivariable analysis, intervention prior to progression (OR 24.18, 95% CI 1.81–1001.27, p = 0.037) and prior tumor control ≥ 12 months (OR 25.39, 95% CI 2.1–1008.9, p = 0.030) independently predicted OS > 24 months. Conclusion: HD-IFO provides durable disease control in selected sarcoma patients, particularly those with sustained prior tumor control and intervention prior to progression.

We report a long-lasting response to the immune checkpoint inhibitor nivolumab in combination with regional hyperthermia (RHT) in a patient with recurrent metastatic Head and Neck Squamous Cell Carcinoma (HNSCC) and negative programmed death ligand 1 (PD-L1) expression. Treatment was well tolerated with no local side effects. Tumor-related symptoms in the orbital and masticator area gradually decreased under treatment with nivolumab and RHT. Over the course of treatment, magnetic resonance imaging (MRI) showed a local tumor control in the heated tumor areas, while metastatic lesions developed in areas outside of the RHT field. This is the first case report demonstrating the feasibility and clinical potential of the addition of RHT in this patient collective with poor outcomes and low response rates to immune checkpoint inhibitors. RHT might be an additional tool to activate an immunogenic milieu responsive to immune checkpoint inhibitors.

Background: The prognostic and predictive value of obesity and sarcopenia remains poorly defined in patients with high-risk soft tissue sarcoma (HR-STS). We sought to correlate clinical outcomes with CT-based body composition parameters in patients with HR-STS undergoing a multimodal preoperative therapy. The impact of radiologic and histopathologic response to preoperative treatment was correlated with individual fat and muscle distribution. Methods: Patients with locally advanced non-abdominal HR-STS and treatment with preoperative chemotherapy + regional hyperthermia (RHT) +/- radiotherapy (RT) followed by surgery between 2015 and 2022 were retrospectively evaluated. Body composition parameters measured on baseline CT scans were correlated with clinical outcomes including event-free survival (EFS) and overall survival (OS) as well as radiologic and histopathologic treatment response. Results: A total of 85 patients were included. Body composition parameters showed no significant correlation with radiologic or histopathologic treatment response. High total fat indices such as the total fat index (TFI, HR 3.56, p = 0.005) and high total fat to muscle ratio (FMR, HR 3.22, p = 0.020) were strongly associated with poor OS. Parameters for sarcopenia including skeletal muscle index (SMI) were not significantly linked to survival outcomes. Conclusion: High fat indices and a high FMR are strong predictors of poor OS in patients with HR-STS. Larger studies are warranted to further clarify the prognostic impact of sarcopenia and the predictive value of body composition parameters on preoperative treatment response.

Background: The current understanding of the prognostic value of routine pre-treatment laboratory parameters in patients with high-risk soft tissue sarcoma (HR-STS) is limited. We sought to analyze several inflammatory biomarkers in a large cohort of HR-STS patients undergoing neoadjuvant therapy followed by curative surgical resection. Methods: 123 patients with locally advanced high-risk undifferentiated pleomorphic sarcoma (UPS), liposarcoma (LPS), leiomyosarcoma (LMS), and synovial sarcoma (SS) who underwent preoperative chemotherapy and regional hyperthermia (RHT) between 2014 and 2022 were retrospectively evaluated. The association of several pre-treatment laboratory parameters with radiologic treatment response, event-free survival (EFS), and overall survival (OS), were analyzed. Results: Low pre-treatment hemoglobin (HR 2.51, p = 0.018; HR 2.78, p = 0.030) and lactate dehydrogenase (LDH, HR 0.29, p = 0.0044; HR 0.23, p = 0.010) were significantly associated with EFS and OS in the multivariable analysis. Systemic inflammatory indices such as the neutrophil-to-lymphocyte ratio (NLR) did not have a significant impact on survival. Low C-reactive protein (CRP) and high albumin values were associated with poor radiologic response according to RECIST (p = 0.021 and p = 0.010, respectively). Conclusion: Pre-treatment LDH and hemoglobin are strong independent predictors of survival in HR-STS patients. Systemic inflammatory indices based on circulating immune cells may not serve as reliable prognostic factors for HR-STS patients undergoing curative-intent treatment. Higher pre-treatment albumin levels and lower CRP values may reflect a reduced inflammatory status and could be associated with a poorer radiologic response to preoperative treatment.

Background: Dacarbazine is currently considered the better combination partner for doxorubicin compared to ifosfamide for the treatment of leiomyosarcoma (LMS). Regional hyperthermia (RHT) combined with neoadjuvant chemotherapy has been shown to improve survival in patients with locally advanced high‐risk STS. We sought to evaluate the role of doxorubicin and dacarbazine (AD) versus doxorubicin and ifosfamide (AI) in combination with RHT in patients with LMS.Methods: Patients with locally advanced high‐grade LMS, including limited metastases, eligible for RHT and first‐line treatment with either AI + RHT or AD + RHT between 2014 and 2022 were retrospectively evaluated. Endpoints were progression‐free survival (PFS) and overall survival (OS). Patients were matched using propensity scores, which were estimated with a logistic regression model accounting for tumor site, presence of metastasis, surgery, and radiotherapy.Results: A total of 105 patients were included in this study, of which 101 were included in the propensity score‐matched cohort. In the matched cohort, treatment with AD + RHT was associated with a significantly improved PFS (HR 0.32, 95% CI 0.13–0.74, p = 0.0081). Multivariable analysis revealed several significant predictors of PFS, including treatment with AD + RHT (HR 0.42, 95% CI 0.19–0.92, p = 0.031).Conclusion: Treatment with AD + RHT showed improved PFS and better treatment tolerability compared to AI + RHT. Our results support the use of AD instead of AI for the treatment of patients with LMS in combination with RHT.

(1) Background: The expression of T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), an immune checkpoint receptor on T cells, has been associated with dismal outcomes and advanced tumor stages in various solid tumors. The blockade of TIM-3 is currently under examination in several clinical trials. This study examines TIM-3 expression in high-risk soft tissue sarcomas (HR-STS). (2) Methods: Tumor cell expression of TIM-3 on protein level was analyzed in pre-treatment biopsies of patients with HR-STS. TIM-3 expression was correlated with clinicopathological parameters including tumor-infiltrating lymphocyte (TIL) counts, programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PDL-1) expression in patients with HR-STS. Survival dependent on the expression of TIM-3 was analyzed. (3) Results: TIM-3 expression was observed in 101 (56%) out of 179 pre-treatment biopsies of patients with HR-STS. TIM-3 expression was significantly more often observed in undifferentiated pleomorphic sarcomas (UPS) compared to other histological subtypes (p < 0.001), high TIL counts (p < 0.001), and high PD-1 (p < 0.001) and PD-L1 expression (p < 0.001). TIM-3 expression did not have a prognostic impact on survival in patients with HR-STS. (4) Conclusions: This is the first study to demonstrate a significant tumor cell expression of TIM-3 in specific subsets of patients with HR-STS. TIM-3 qualifies as a potential immunotherapeutic target in HR-STS.