Soft Tissue Sarcoma Research Articles

Predictive and dynamic signature for anti-angiogenics in combination with PD-1 inhibitor in soft-tissue sarcoma: correlative studies linked to the IMMUNOSARC trial.

IMMUNOSARC trial combined an anti-angiogenic agent (sunitinib) with a PD-1 inhibitor (nivolumab) in advanced sarcomas. Here we present the first correlative studies of the STS cohort enrolled in this trial. Formalin-fixed paraffin-embedded (FFPE) and peripheral blood samples were collected at baseline and week 13. FFPE were used for transcriptomics and multiplex immunofluorescence, while peripheral blood samples were used for multiplexed immunoassays. Flow cytometry and Luminex assays were performed to validate translational findings in tumor-isolated cells and peripheral blood mononuclear cells derived from patients. The density of intratumoral CD8+ T cells, measured by multiplexed immuno-phenotyping, was significantly increased after treatment. This augment was accompanied by the dynamic significant increase in gene expression of CD86, CHI3L1, CXCL10, CXCL9, LAG3, and VCAM1, and the decrease in the expression levels of NR4A1. In peripheral blood, 12 proteins were significantly modulated by treatment at W13. A score integrating the dynamic expression of the 7 genes and the 12 soluble factors separated two groups with distinct progression-free survival (PFS): 4.1 months (95% CI 3.5-NR) vs 17 months (95% CI 12.0 - NR), p=0.014. This molecular score was predictive of PFS when applied to the normalized data determined in the baseline samples. Treatment with sunitinib and nivolumab inflamed the sarcoma microenvironment, increasing CD8+ T cell density and the expression of several genes/ proteins with relevance in the response to PD-1 inhibitors. A molecular signature identified two groups of patients with distinct PFS for the combination of anti-angiogenics plus PD-1 inhibitor.

A phase II, open-label, single-arm trial of pembrolizumab for recurrent meningioma and solitary fibrous tumor.

Atypical and anaplastic meningiomas account for 20% of all meningioma cases. Solitary fibrous tumor (SFT) is a type of soft tissue sarcoma with similar attributes to meningioma. For patients with refractory or recurrent disease after previous surgery or radiotherapy, there is no effective treatment. Pembrolizumab, an anti-programmed cell death 1 (PD-1) antibody, is an effective treatment for various solid tumors. PD-1 ligand is highly expressed in aggressive meningiomas. We aimed to assess the effectiveness of pembrolizumab in treating meningioma and SFT recurrence after surgery and radiation therapy. This prospective single-arm phase II trial comprised 15 patients with recurrent meningioma and 3 with anaplastic SFT, treated at a single institution during 2018 to 2022. The study was terminated due to a lack of efficacy and slow accrual. The primary endpoint was 6-month progression-free survival (PFS-6). Median progression-free survival (PFS) was 2.6 months, and median overall survival (OS) was 40 months. The 6- and 12-month PFS were both 11.1%. The 6- and 12-month OS were 94.4% and 61.1%, respectively. According to the Response Assessment in Neuro-Oncology (RANO) criteria, the overall response rate was 11%, with 2 patients achieving stable disease and 2 with partial response. Three patients (16.7%) developed grade 3 toxicity. Our results showed that pembrolizumab failed to improve PFS-6 in patients with aggressive meningioma or anaplastic SFT. However, two patients, one with atypical meningioma and one with anaplastic SFT, achieved a partial response. More clinical studies are needed to identify which subset of patients may benefit from this treatment.

Gastric Undifferentiated Pleomorphic Sarcoma Presenting as a Rapidly Growing Subepithelial Tumor

A 48-year-old man presented to our hospital for evaluation of melena. Abdominal computed tomography (CT) revealed an endophytic contrast-enhanced mass (approximately 9 cm) in the gastric fundus and upper body. CT showed no evidence of metastasis to other organs. Endoscopic examination revealed a large mass accompanied by an exudate and signs of surface hemorrhage. The shape of the mass resembled that of a subepithelial tumor, and >50% of the mucosa was peeled off. Endoscopic ultrasonography revealed hyperechoic spreading and dotor rod-shaped anechoic lesions arranged within an overall hypoechoic mass. The patient underwent total gastrectomy with lymph node dissection and was diagnosed with undifferentiated pleomorphic sarcoma without lymph node metastasis. Undifferentiated pleomorphic sarcoma, a high-grade aggressive soft tissue sarcoma, predominantly involves the extremities and rarely the stomach. It is usually asymptomatic but tends to grow rapidly. Endoscopic imaging performed a year prior to presentation was unremarkable. We report a case of a gastric undifferentiated pleomorphic sarcoma that presented as a rapidly growing subepithelial tumor. Malignancies other than a gastrointestinal stromal tumor should be considered in the differential diagnosis in patients presenting with a rapidly growing gastric subepithelial tumor.

MEK inhibitors lead to PDGFR pathway upregulation and sensitize tumors to RAF dimer inhibitors in NF1-deficient malignant peripheral nerve sheath tumor (MPNST).

Malignant peripheral nerve sheath tumor (MPNST) is a highly aggressive subtype of soft tissue sarcoma with a high propensity to metastasize and extremely limited treatment options. Loss of the RAS-GAP NF1 leads to sustained RAF/MEK/ERK signaling in MPNST. However, single-agent MEK inhibitors (MEKi) have failed to elicit a sustained inhibition of the MAPK signaling pathway in MPNST. We employed pharmacological, biochemical, and genetic perturbations of the receptor tyrosine kinase (RTK) and MAPK signaling pathway regulators to investigate the mechanisms of MEKi resistance and evaluated combination therapeutic strategies in various preclinical MPNST models in vitro and in vivo. Here, we report that MEKi treatment resistance in MPNST involves two adaptive pathways: direct transcriptional upregulation of the receptor tyrosine kinase (RTK) PDGFRβ, and MEKi-induced increase in RAF dimer formation and activation of downstream signaling. While the pharmacological combination of MEKi with a PDGFRβ specific inhibitor was more effective than treatment with MEKi alone, the combination of MEKi and RAF-dimer inhibitors led to a robust inhibition of the MAPK pathway signaling. This combination treatment was effective in vitro and in vivo, as demonstrated by the significant increase in drug synergism and its high effectiveness in decreasing MPNST viability. Our findings suggest that the combination of MEKi and PDGFR and/or RAF dimer inhibitors can overcome MEKi resistance and may serve as a novel targeted therapeutic strategy for NF1-deficient MPNST patients, which in turn could impact future clinical investigations for this patient population.

Neo-adjuvant radiation and intratumoral immunotherapy followed by surgery-NARIS trial for extremity soft tissue sarcoma.

Extremity soft tissue sarcoma (ESTS) is a rare malignant nonepithelial disease, calling for combined modality treatments with surgery to further improve local control rates and long-term survival, especially in patients with multiple local recurrences with or without risk of amputation. In this double-arm, open-label, Phase II clinical trial, we will enroll 30 patients with pathologically confirmed ESTS without nodal involvement or distant metastases. Patients are randomly assigned to the combination treatment group or the radiation monotherapy group. Additionally, tumor and biological samples will be obtained directly before and after neoadjuvant therapy, allowing for studies of immune response and primary drug resistance mechanisms.Clinical Trial Registration: ChiCTR2200060659 (http://www.chictr.org.cn) (ClinicalTrials.gov).

Cellular origin and clonal evolution of human dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is the most frequent high-grade soft tissue sarcoma subtype. It is characterized by a component of undifferentiated tumor cells coexisting with a component of well-differentiated adipocytic tumor cells. Both dedifferentiated (DD) and well-differentiated (WD) components exhibit MDM2 amplification, however their cellular origin remains elusive. Using single-cell RNA sequencing, DNA sequencing, in situ multiplex immunofluorescence and functional assays in paired WD and DD components from primary DDLPS tumors, we characterize the cellular heterogeneity of DDLPS tumor and micro-environment. We identify a population of tumor adipocyte stem cells (ASC) showing striking similarities with adipocyte stromal progenitors found in white adipose tissue. We show that tumor ASC harbor the ancestral genomic alterations of WD and DD components, suggesting that both derive from these progenitors following clonal evolution. Last, we show that DD tumor cells keep important biological properties of ASC including pluripotency and that their adipogenic properties are inhibited by a TGF-β-high immunosuppressive tumor micro-environment.

Soft tissue sarcomas associated with neurofibromatosis: treatment experience

Soft tissue sarcomas associated with neurofibromatosis: treatment experience

Twenty-five years of experience with patient-reported outcome measures in soft-tissue sarcoma patients: a systematic review.

As the importance of the patient's perspective on treatment outcome is becoming increasingly clear, the availability of patient-reported outcome measures (PROMs) has grown accordingly. There remains insufficient information regarding the quality of PROMs in patients with soft-tissue sarcomas (STSs). The objectives of this systematic review were (1) to identify all PROMs used in STS patients and (2) to critically appraise the methodological quality of these PROMs. Literature searches were performed in MEDLINE and Embase on April 22, 2024. PROMs were identified by including all studies that evaluate (an aspect of) health-related quality of life in STS patients by using a PROM. Second, studies that assessed measurement properties of the PROMs utilized in STS patients were included. Quality of PROMs was evaluated by performing a COSMIN analysis. In 59 studies, 39 PROMs were identified, with the Toronto Extremity Salvage Score (TESS) being the most frequently utilized. Three studies evaluated methodological quality of PROMs in the STS population. Measurement properties of the TESS, Quick Disability of the Arm, Shoulder and Hand (QuickDASH) and European Organization for Research and Treatment for Cancer Quality of Life Questionnaire (EORTC-QLQ-C30) were reported. None of the PROMs utilized in the STS population can be recommended for use based on the current evidence and COSMIN analysis. To ensure collection of reliable outcomes, PROMs require methodological evaluation prior to utilization in the STS population. Research should prioritize on determining relevant content and subsequently selecting the most suitable PROM for assessment.

Omics technologies in diagnosis and treatment of soft tissue sarcomas

Omics technologies in diagnosis and treatment of soft tissue sarcomas

Separable cell cycle arrest and immune response elicited through pharmacological CDK4/6 and MEK inhibition in RASmut disease models.

The combination of CDK4/6 and MEK inhibition as a therapeutic strategy has shown promise in various cancer models, particularly in those harboring RAS mutations. An initial high-throughput drug screen identified a high synergy between the CDK4/6 inhibitor palbociclib and the MEK inhibitor trametinib when used in combination in soft tissue sarcomas. In RAS mutant models, combination treatment with palbociclib and trametinib induced significant G1 cell cycle arrest, resulting in a marked reduction in cell proliferation and growth. CRISPR-mediated RB1 depletion resulted in a decreased response to CDK4/6 and MEK inhibition, which was validated in both cell culture and xenograft models. Beyond its cell cycle inhibitory effects, pathway enrichment analysis revealed the robust activation of interferon pathways upon CDK4/6 and MEK inhibition. This induction of gene expression was associated with the upregulation of retroviral elements. The TBK1(TANK-binding kinase 1) inhibitor GSK8612 selectively blocked the induction of interferon-related genes induced by palbociclib and trametinib treatment, and highlighted the separable epigenetic responses elicited by combined CDK4/6 and MEK inhibition. Together, these findings provide key mechanistic insights into the therapeutic potential of CDK4/6 and MEK inhibition in soft tissue sarcoma.

The tumor microenvironment in therapy resistance

Chemotherapy alone or in conjunction with surgery and radiation is often used to treat various cancer types. While effective at treating some tumors, the response varies across patients with different malignancies. For some cancers, such as glioblastoma, ovarian cancer, and soft tissue sarcoma, 85%–100% of patients experience cancer recurrence and develop chemotherapy resistance, which often leads to worse prognoses. These alarming statistics highlight an urgent need to better understand the landscape of therapy resistance in cancer, in order to develop improved treatment strategies and prevent recurrence. A central focus has been the investigation of resistant tumor subclones and whether the use of different alkylating agents and/or immune checkpoint inhibitors can ablate different clones. However, very little effort has been directed towards studies of the tumor microenvironment, a complex ecosystem of blood vessels, fibroblasts, immune cells, signaling molecules, and extracellular matrix, in the context of therapy resistance. In this perspective, we provide an overview of different platforms, tools, and techniques that have been developed and used to identify tumor microenvironment alterations due to therapy resistance. We also address potential therapeutic strategies that involve components of the tumor milieu and have been identified and tested to overcome treatment-induced resistance. Identifying microenvironmental changes post-resistance presents opportunities for new targeted treatment strategies. The current state of the literature suggests a dire need for more engineered models that probe specific microenvironment contributors to therapy resistance or ways in which the tumor tissue can be harnessed to mitigate resistance.

Whole Lung Irradiation in Rhabdomyosarcoma With Lung Metastases: A Report From the Soft Tissue Sarcoma Committee of the Children's Oncology Group.

Patients with rhabdomyosarcoma with metastatic disease have a poor prognosis despite therapy intensification. The aim of this study was to investigate the efficacy of whole lung irradiation (WLI) in patients with rhabdomyosarcoma and lung metastases. Patients with rhabdomyosarcoma with lung metastases enrolled on four Children's Oncology Group protocols (D9802, D9803, ARST08P1, ARST0431) were retrospectively reviewed. Event-free survival (EFS) and overall survival (OS) were compared between patients who received and did not receive WLI. In 143 patients with rhabdomyosarcoma with lung metastases, 65 patients (45.5%) received WLI and 78 patients (54.5%) did not receive WLI despite protocol requirements. The 5-year EFS was 38.3% (95% CI, 24.8 to 51.8) in patients who received WLI and 25.2% (95% CI, 13.8 to 36.6) in patients who did not receive WLI (P = .0496). The 5-year OS was 45.5% (95% CI, 31.8 to 59.3) in patients who received WLI and 32.4% (95% CI, 20.4 to 44.4) in patients who did not receive WLI (P = .08). In exploratory subgroup analyses, the benefit of WLI on EFS and OS was significant in patients 10 years and older. Other clinical factors associated with EFS on univariable analysis included age, histology FOXO1 fusion status, number of metastatic sites, location of metastatic sites, and Oberlin Score. WLI is associated with improved EFS in patients with rhabdomyosarcoma with lung metastases. These results highlight the potential importance of WLI and need for more stringent protocol compliance for administering WLI.

The application of lung immune prognostic index in predicting the prognosis of 302 STS patients.

Soft tissue sarcoma (STS) are heterogeneous and rare tumors, and few studies have explored predicting the prognosis of patients with STS. The Lung Immune Prognostic Index (LIPI), calculated based on baseline serum lactate dehydrogenase (LDH) and the derived neutrophils/(leukocytes minus neutrophils) ratio (dNLR), was considered effective in predicting the prognosis of patients with pulmonary cancer and other malignancies. However, the efficacy of the LIPI in predicting the prognosis of patients with STS remains unclear. This study retrospectively reviewed patients with STS admitted to our center from January 2016 to January 2021. Their hematological and clinical characteristics were collected and analyzed to construct the LIPI specific to STS. The correlations between various predictive factors and overall survival (OS) were examined using Kaplan-Meier and Cox regression analyses. Independent risk factors for OS were identified using univariate and multivariate analyses. Finally, a LIPI nomogram model for STS was established. This study enrolled 302 patients with STS, of which 87 (28.9%), 162 (53.6%), and 53 (17.5%) were classified into three LIPI-based categories: good, moderate, and poor, respectively (P < 0.0001). The time-dependent operator curve showed that the LIPI had better prognostic predictive ability than other hematological and clinical characteristics. Univariate and multivariate analyses identified the Fédération Nationale des Centres de Lutte Contre le Cancer grade (FNCLCC/G), tumor size, and LIPI as independent risk factors. Finally, a nomogram was constructed by integrating the significant prognostic factors. Its C-index was 0.72, and the calibration curve indicated that it could accurately predict the three- and five-year OS of patients with STS. The decision and clinical impact curves also indicated that implementing this LIPI-nomogram could significantly benefit patients with STS. This study explored the efficacy of the LIPI in predicting the prognosis of 302 patients with STS, classifying them into three categories to evaluate the prognosis. It also reconstructed a LIPI-based nomogram to assist clinicians in predicting the three- and five-year OS of patients with STS, potentially enabling timely intervention and customized management.

SP9.10 - The Sarcoma Hub and Spoke Diagnostic Service Can be Safely and Effectively Rolled-Out and Continued

Abstract Aims To understand the safety and effectiveness of the newly established Sarcoma Hub and Spoke Service (SHSS) in detecting malignancies through assessment of the performance of one Spoke Service in triaging lesions of concern. Methods Patients referred to our Diagnostic Service on the 2 week-wait pathway (2WW) and have had their lesion(s) of interest removed between an 18-month period were identified from our Hospital Information System. Data was collected for post-op histology, suspicion of diagnosis in the pre-op MDT, compatibility between the two, and whether patient was cleared from suspicion of malignancy before removal of the lesion. Results 119 patients meeting the criteria were identified. 90 had been cleared of suspicion for malignancy prior to surgery. 83/90 of these had samples sent for histology, yielding 82 benign and 1 malignant (dermatofibrosarcoma protruberans) results. Of the 29 patients who had excision biopsy on the 2WW, 5/29 returned histology for risk of (e.g. possible sarcoma or atypical lipoma) or confirmed malignancies. 46/119 cases were discussed at our SHSS MDT and have both pre-op MDT diagnosis records and histology results; 37/46 of these were compatible – all correctly predicted benign pathologies. Where pre-op MDT diagnosis and histology were incompatible, 1/9 predicted benign diagnosis but returned malignant histology. Conclusion Our SHSS Diagnostic Service’s process of triaging lesions concerning for sarcoma, including our MDT and surgical excision biopsies, is accurate. Preliminary data shows that the Sarcoma Hub and Spoke Service is a safe way to aid in diagnosing or ruling out soft tissue sarcoma.

TLE1 Expression in Different Sarcoma Types and its Relation to Clinicopathological Parameters

Background and objectives: Split genes that contain Transducin-Like Enhancer encode transcriptional corepressors that are essential for hematopoiesis and embryogenesis in humans. Synovial sarcomas express Transducin-Like Enhancer-1, a distinct factor which hardly has been shown in other soft tissues malignancies. Transducin-Like Enhancer-1 expression was recently found to be sensitive but not entirely specific for synovial sarcoma. Methods: This retrospective study included eighty paraffin embedded formalin-fixed blocks of different sarcomas which were gathered and picked out of the files of Rizgary teaching hospital lab and from certain private labs in Hawler, during June 2015-December 2022. In this study, Transducin-Like Enhancer-1, a mouse monoclonal antibody was applied on sarcoma cases and its expression was assessed. Results: around one third (30%) of the patients had synovial sarcoma, (16.3%) had undifferentiated pleomorphic sarcoma, and the rest had other types. More than half (55%) of the sarcomas were of high grade, and the Transducin-Like Enhancer-1 score was strongly reactive in 33.8% of the patients. It was also strong in all (100%) the patients with synovial sarcoma, compared with 23.1% of patients with undifferentiated pleomorphic sarcoma, and 0% of the other types of sarcoma (p &lt; 0.001). Conclusion: this study demonstrates that, when synovial sarcoma was kept in the differential diagnosis of spindle cell soft tissue sarcomas, Transducin-Like Enhancer-1 was a highly sensitive and relatively a specific marker.

Disruptions in antigen processing and presentation machinery on sarcoma

BackgroundThe antigen processing machinery (APM) plays a critical role in generating tumor-specific antigens that can be recognized and targeted by the immune system. Proper functioning of APM components is essential for presenting these antigens on the surface of tumor cells, enabling immune detection and destruction. In many cancers, defects in APM can lead to immune evasion, contributing to tumor progression and poor clinical outcomes. However, the status of the APM in sarcomas is not well characterized, limiting the development of effective immunotherapeutic strategies for these patients.MethodsWe investigated 126 patients with 8 types of bone and soft tissue sarcoma operated between 2001–2021. Tissue microarrays mapped 11 specific areas in each case. The presence/absence of APM protein was determined through immunohistochemistry. Bayesian networks were used.ResultsAll investigated sarcomas had some defects in APM. The least damaged component was HLA Class I subunit β2-microglobulin and HLA Class II. The proteasome LMP10 subunit was defective in leiomyosarcoma (LMS), myxoid liposarcoma (MLPS), and dedifferentiated liposarcoma (DDLPS), while MHC I transporting unit TAP2 was altered in undifferentiated pleomorphic sarcoma (UPS), gastrointestinal stromal tumor (GIST), and chordoma (CH). Among different neoplastic areas, high-grade areas showed different patterns of expression compared to high lymphocytic infiltrate areas. Heterogeneity at the patient level was also observed. Loss of any APM component was prognostic of distant metastasis (DM) for LMS and DDLPS and of overall survival (OS) for LMS.ConclusionSarcomas exhibit a high degree of defects in APM components, with differences among histotypes and tumoral areas. The most commonly altered APM components were HLA Class I subunit β2-microglobulin, HLA Class I subunit α (HC10), and MHC I transporting unit TAP2. The loss of APM components was prognostic of DM and OS and clinically relevant for LMS and DDLPS. This study explores sarcoma molecular mechanisms, enriching personalized therapeutic approaches.

Mandibular Rhabdomyosarcoma in an Eniente Woman: About a Case

Introduction: Rhabdomyosarcoma is the most common soft tissue sarcoma in patients under 25 years of age. The occurrence of mandibular rhabdomyosarcoma in a pregnant woman is rare with an incidence of 0.07 to 0.1 and the literature describes one case per 1000 deliveries. Only biopsy and histological examination make a definitive diagnosis. Treatment is based on a combination of chemoradiation and surgery. Objectives: To describe the diagnostic and therapeutic aspects of mandibular rhabdomyosarcoma in pregnant women. Observation: It was a 19-year-old patient who had consulted for left mandibular swelling evolving over 28 weeks. A morphological assessment had been requested but being almost full-term, the patient chose to let her pregnancy progress. She was seen again after delivery with a swelling that had tripled in volume with abundant bleeding on the alteration of the general condition. The imaging concluded that there was a large osteolytic mass of the mandible. The biopsy performed came back in favor of an infiltrating pleomorphic rhabdomyosarcoma. Treatment consisted of radiation therapy followed by surgery. The evolution was marked by the death of the patient after 01 month of radiotherapy. Conclusion: Rhabdomyosarcoma is an aggressive malignant tumor that most often affects subjects under 25 years of age and its appearance in pregnant women is rare.

Radiomics of multi-parametric MRI for the prediction of lung metastasis in soft-tissue sarcoma: a feasibility study

PurposeTo investigate the value of multi-parametric MRI-based radiomics for preoperative prediction of lung metastases from soft tissue sarcoma (STS).MethodsIn total, 122 patients with clinicopathologically confirmed STS who underwent pretreatment T1-weighted contrast-enhanced (T1-CE) and T2-weighted fat-suppressed (T2FS) MRI scans were enrolled between Jul. 2017 and Mar. 2021. Radiomics signatures were established by calculating and selecting radiomics features from the two sequences. Clinical independent predictors were evaluated by statistical analysis. The radiomics nomogram was constructed from margin and radiomics features by multivariable logistic regression. Finally, the study used receiver operating characteristic (ROC) and calibration curves to evaluate performance of radiomics models. Decision curve analyses (DCA) were performed to evaluate clinical usefulness of the models.ResultsThe margin was considered as an independent predictor (p < 0.05). A total of 4 MRI features were selected and used to develop the radiomics signature. By incorporating the margin and radiomics signature, the developed nomogram showed the best prediction performance in the training (AUCs, margin vs. radiomics signature vs. nomogram, 0.609 vs. 0.909 vs. 0.910) and validation (AUCs, margin vs. radiomics signature vs. nomogram, 0.666 vs. 0.841 vs. 0.894) cohorts. DCA indicated potential usefulness of the nomogram model.ConclusionsThis feasibility study evaluated predictive values of multi-parametric MRI for the prediction of lung metastasis, and proposed a nomogram model to potentially facilitate the individualized treatment decision-making for STSs.

A multimodal neural network with gradient blending improves predictions of survival and metastasis in sarcoma

The objective of this study is to develop a multimodal neural network (MMNN) model that analyzes clinical variables and MRI images of a soft tissue sarcoma (STS) patient, to predict overall survival and risk of distant metastases. We compare the performance of this MMNN to models based on clinical variables alone, radiomics models, and an unimodal neural network. We include patients aged 18 or older with biopsy-proven STS who underwent primary resection between January 1st, 2005, and December 31st, 2020 with complete outcome data and a pre-treatment MRI with both a T1 post-contrast sequence and a T2 fat-sat sequence available. A total of 9380 MRI slices containing sarcomas from 287 patients are available. Our MMNN accepts the entire 3D sarcoma volume from T1 and T2 MRIs and clinical variables. Gradient blending allows the clinical and image sub-networks to optimally converge without overfitting. Heat maps were generated to visualize the salient image features. Our MMNN outperformed all other models in predicting overall survival and the risk of distant metastases. The C-Index of our MMNN for overall survival is 0.77 and the C-Index for risk of distant metastases is 0.70. The provided heat maps demonstrate areas of sarcomas deemed most salient for predictions. Our multimodal neural network with gradient blending improves predictions of overall survival and risk of distant metastases in patients with soft tissue sarcoma. Future work enabling accurate subtype-specific predictions will likely utilize similar end-to-end multimodal neural network architecture and require prospective curation of high-quality data, the inclusion of genomic data, and the involvement of multiple centers through federated learning.

Abstract IA004: Risk of therapy-related subsequent cancers in individuals with germline TP53 variants

Abstract Background. Based primarily on in vitro and animal studies, germline TP53 variants are considered to confer sensitivity to ionizing radiation-induced DNA damage, but data in humans are sparse. We sought to quantify risk of developing radiotherapy and chemotherapy-related subsequent neoplasms by pooling individual-level data from nine cohorts of individuals with confirmed pathogenic/likely pathogenic germline TP53 variants. Methods. 891 individuals were followed from six months after first cancer until diagnosis of a subsequent neoplasm, death or date of last follow-up. Radiotherapy and chemotherapy for each cancer were considered as time-dependent covariates in Cox regression models with age as the time-scale, adjusted for sex and occurrence of prior malignant or benign tumors. Subsequent cancers were classified as in- or out-of-field based on the body region of previous cancers. Results. Among 891 individuals, 643 (72.2%) were female and 297 (33.3%) were diagnosed with a first cancer before age 20 years. Breast cancer was the most commonly diagnosed first cancer (N=371), followed by soft tissue sarcoma (N=131) and central nervous system cancers (N=84). First cancer treatment included radiotherapy for 237 (26.6%) and/or chemotherapy for 421 (47.3%) individuals. Analyses are underway to define the characteristics of subsequent neoplasms (including age at diagnosis, latency, and distribution of diagnosis type) and to calculate relative and absolute risk estimates for radiotherapy and chemotherapy overall and by subsequent neoplasm type. Conclusions. This study will quantify the contribution of radiotherapy and chemotherapy to the risk of subsequent cancers among individuals with Li-Fraumeni syndrome. Understanding the magnitude of this risk will support health care providers and patients in making informed decisions about cancer management. Citation Format: Anita Villani, Payal Khincha, Jessica Hatton, Sara Schonfeld, Catherine Goudie, Leatrisse Oba, Kishan Pithadia, Birte Sänger, Christian Kratz, Anh N. Le, Caitlin Orr, Kara N. Maxwell, Anne Naumer, Jennie Vagher, Wendy Kohlmann, Joshua Schiffman, Elizabeth Santana dos Santos, Orli Michaeli, Jacob J. Carson, Derek S. Tsang, Raymond Kim, Jamie L. Maciaszek, Kim E. Nichols, Victoria E. Goodman, Suzanne P. MacFarland, Lara Reichman, Maria Isabel Achatz, Sharon Savage, David Malkin, Lindsay M. Morton. Risk of therapy-related subsequent cancers in individuals with germline TP53 variants [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pediatric Cancer Research; 2024 Sep 5-8; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl):Abstract nr IA004.