Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial.

BACKGROUND: Afamitresgene autoleucel (afami-cel) showed acceptable safety and promising efficacy in a phase 1 trial (NCT03132922). The aim of this study was to further evaluate the efficacy of afami-cel for the treatment of patients with HLA-A*02 and MAGE-A4-expressing advanced synovial sarcoma or myxoid round cell liposarcoma. METHODS: SPEARHEAD-1 was an open-label, non-randomised, phase 2 trial done across 23 sites in Canada, the USA, and Europe. The trial included three cohorts, of which the main investigational cohort (cohort 1) is reported here. Cohort 1 included patients with HLA-A*02, aged 16-75 years, with metastatic or unresectable synovial sarcoma or myxoid round cell liposarcoma (confirmed by cytogenetics) expressing MAGE-A4, and who had received at least one previous line of anthracycline-containing or ifosfamide-containing chemotherapy. Patients received a single intravenous dose of afami-cel (transduced dose range 1·0 × 109-10·0 × 109 T cells) after lymphodepletion. The primary endpoint was overall response rate in cohort 1, assessed by a masked independent review committee using Response Evaluation Criteria in Solid Tumours (version 1.1) in the modified intention-to-treat population (all patients who received afami-cel). Adverse events, including those of special interest (cytokine release syndrome, prolonged cytopenia, and neurotoxicity), were monitored and are reported for the modified intention-to-treat population. This trial is registered at ClinicalTrials.gov, NCT04044768; recruitment is closed and follow-up is ongoing for cohorts 1 and 2, and recruitment is open for cohort 3. FINDINGS: Between Dec 17, 2019, and July 27, 2021, 52 patients with cytogenetically confirmed synovial sarcoma (n=44) and myxoid round cell liposarcoma (n=8) were enrolled and received afami-cel in cohort 1. Patients were heavily pre-treated (median three [IQR two to four] previous lines of systemic therapy). Median follow-up time was 32·6 months (IQR 29·4-36·1). Overall response rate was 37% (19 of 52; 95% CI 24-51) overall, 39% (17 of 44; 24-55) for patients with synovial sarcoma, and 25% (two of eight; 3-65) for patients with myxoid round cell liposarcoma. Cytokine release syndrome occurred in 37 (71%) of 52 of patients (one grade 3 event). Cytopenias were the most common grade 3 or worse adverse events (lymphopenia in 50 [96%], neutropenia 44 [85%], leukopenia 42 [81%] of 52 patients). No treatment-related deaths occurred. INTERPRETATION: Afami-cel treatment resulted in durable responses in heavily pre-treated patients with HLA-A*02 and MAGE-A4-expressing synovial sarcoma. This study shows that T-cell receptor therapy can be used to effectively target solid tumours and provides rationale to expand this approach to other solid malignancies. FUNDING: Adaptimmune.

Safety and efficacy of percutaneous image-guided ablation for soft tissue sarcoma metastases to the liver.

PURPOSE: To evaluate outcomes following percutaneous image-guided ablation of soft tissue sarcoma metastases to the liver. MATERIALS AND METHODS: A single-institution retrospective analysis of patients with a diagnosis of metastatic soft tissue sarcoma who underwent percutaneous image-guided ablation of hepatic metastases between January 2011 and December 2021 was performed. Patients with less than 60 days of follow-up after ablation were excluded. The primary outcome was local tumor progression-free survival (LPFS). Secondary outcomes included overall survival, liver-specific progression-free survival. and chemotherapy-free survival. RESULTS: Fifty-five patients who underwent percutaneous ablation for 84 metastatic liver lesions were included. The most common histopathological subtypes were leiomyosarcoma (23/55), followed by gastrointestinal stromal tumor (22/55). The median treated liver lesions was 2 (range, 1-8), whereas the median size of metastases were 1.8 cm (0.3-8.7 cm). Complete response at 2 months was achieved in 90.5% of the treated lesions. LPFS was 83% at 1 year and 80% at 2 years. Liver-specific progression-free survival was 66% at 1 year and 40% at 2 years. The overall survival at 1 and 2 years was 98% and 94%. The chemotherapy-free holiday from the start of ablation was 71.2% at 12 months. The complication rate was 3.6% (2/55); one of the complications was Common Terminology Criteria for Adverse Events grade 3 or higher. LPFS subgroup analysis for leiomyosarcoma versus gastrointestinal stromal tumor suggests histology-agnostic outcomes (2 years, 89% vs 82%, p = .35). CONCLUSION: Percutaneous image-guided liver ablation of soft tissue sarcoma metastases is safe and efficacious.

Durvalumab plus tremelimumab in advanced or metastatic soft tissue and bone sarcomas: a single-centre phase 2 trial.

BACKGROUND: Few standard treatment options are available for patients with metastatic sarcomas. We did this trial to evaluate the efficacy, safety, and changes in the tumour microenvironment for durvalumab, an anti-PD-L1 drug, and tremelimumab, an anti-CTLA-4 drug, across multiple sarcoma subtypes. METHODS: In this single-centre phase 2 trial, done at The University of Texas MD Anderson Cancer Center (Houston, TX USA), patients aged 18 years or older with advanced or metastatic sarcoma with an Eastern Cooperative Oncology Group performance status of 0 or 1 who had received at least one previous line of systemic therapy were enrolled in disease subtype-specific groups (liposarcoma, leiomyosarcoma, angiosarcoma, undifferentiated pleomorphic sarcoma, synovial sarcoma, osteosarcoma, alveolar soft-part sarcoma, chordoma, and other sarcomas). Patients received 1500 mg intravenous durvalumab and 75 mg intravenous tremelimumab for four cycles, followed by durvalumab alone every 4 weeks for up to 12 months. The primary endpoint was progression-free survival at 12 weeks in the intention-to-treat population (all patients who received at least one dose of treatment). Safety was also analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02815995, and is completed. FINDINGS: Between Aug 17, 2016, and April 9, 2018, 62 patients were enrolled, of whom 57 (92%) received treatment and were included in the intention-to-treat population. With a median follow-up of 37·2 months (IQR 1·8-10·1), progression-free survival at 12 weeks was 49% (95% CI 36-61). 21 grade 3-4 treatment-related adverse events were reported, the most common of which were increased lipase (four [7%] of 57 patients), colitis (three [5%] patients), and pneumonitis (three [5%] patients). Nine (16%) patients had a treatment related serious adverse event. One patient had grade 5 pneumonitis and colitis. INTERPRETATION: The combination of durvalumab and tremelimumab is an active treatment regimen for advanced or metastatic sarcoma and merits evaluation in specific subsets in future trials. FUNDING: AstraZeneca.

Outcomes of systemic therapy in metastatic phyllodes tumor of the breast.

PURPOSE: Metastatic phyllodes tumors of the breast (MPT) are rare breast neoplasms, limiting development of standardized treatment approaches. We sought to characterize the largest group of MPT thus far reported, evaluating systemic therapy outcomes. METHODS: Adult patients diagnosed with MPT between 1993 and 2015 and followed at MD Anderson Cancer Center were selected for retrospective chart review. Systemic therapy was sorted into: adriamycin/ifosfamide (AI), other anthracycline regimens, other ifosfamide regimens, gemcitabine-based regimens, and other. Given one patient may have received more than one regimen, we assumed that the effects of each regimen were independent from previous therapy. Median overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method. Log-rank test was performed to evaluate the difference in OS between patient characteristics groups, and the differences in PFS between the five chemotherapy regimens. RESULTS: We identified 50 MPT patients, with 31 patients receiving 61 systemic regimens. Median OS was 10.7 months (95% CI: 8.67, 16.5). AI had a PFS of 9.10 months (95% CI: 5.03, 14.2), other ifosfamide regimens had a PFS of 5.10 months (95% CI: 0.67, 12.1), other anthracycline regimens had a PFS of 3.65 months (95% CI: 1.17, 7.90), gemcitabine-based regimens had a PFS of 2.80 months (95% CI: 1.83, 4.60), and other regimens had a PFS of 1.67 months (95% CI: 1.13, 7.77). CONCLUSION: MPT patients are a unique population with limited characterization to date. Our study demonstrates activity of multiple sarcoma-directed chemotherapy regimens, with ifosfamide-containing regimens having the longest PFS.

Results of a prospective phase 2 study of pazopanib in patients with surgically unresectable or metastatic chondrosarcoma.

BACKGROUND: This single-arm, multicenter, phase 2 study evaluated the safety and antitumor activity of pazopanib in patients with unresectable or metastatic conventional chondrosarcoma. METHODS: Eligible patients had conventional chondrosarcoma of any grade with measurable tumors that were unresectable or metastatic. Patients with mesenchymal, dedifferentiated, and extraskeletal myxoid chondrosarcoma subtypes and patients who received prior tyrosine kinase inhibitor therapy were excluded. Pazopanib at 800 mg once daily was administered for 28-day cycles. Tumor responses were evaluated by local radiology assessments every 2 cycles. The primary endpoint was the disease control rate (DCR) at week 16 (4 cycles). RESULTS: Forty-seven patients were enrolled. The DCR at 16 weeks was 43% (95% confidence interval [CI], 28%-58%), which was superior to the null hypothesis rate of 30%, but the 2-sided P value (exact test) was .09 (1-sided P = .045). One patient had a partial response. The median overall survival was 17.6 months (95% CI, 11.3-35.0 months), and the median progression-free survival was 7.9 months (95% CI, 3.7-12.6 months). Grade 3 or higher adverse events were infrequent; hypertension (26%) and elevated alanine aminotransferase (9%) were most common. CONCLUSIONS: This study provides evidence of positive drug activity for pazopanib in conventional chondrosarcoma.

Synovial Sarcoma: A Complex Disease with Multifaceted Signaling and Epigenetic Landscapes.

PURPOSE OF REVIEW: Aside from a characteristic SS18-SSX translocation identified in almost all cases, no genetic anomalies have been reliably isolated yet to drive the pathogenesis of synovial sarcoma. In the following review, we explore the structural units of wild-type SS18 and SSX, particularly as they relate to the transcriptional alterations and cellular pathway changes imposed by SS18-SSX. RECENT FINDINGS: Native SS18 and SSX contribute recognizable domains to the SS18-SSX chimeric proteins, which inflict transcriptional and epigenetic changes through selective protein interactions involving the SWI/SNF and Polycomb chromatin remodeling complexes. Multiple oncogenic and developmental pathways become altered, collectively reprogramming the cellular origin of synovial sarcoma and promoting its malignant transformation. Synovial sarcoma is characterized by complex epigenetic and signaling landscapes. Identifying the operational pathways and concomitant genetic changes induced by SS18-SSX fusions could help develop tailored therapeutic strategies to ultimately improve disease control and patient survivorship.

Synovial Sarcoma: Advances in Diagnosis and Treatment Identification of New Biologic Targets to Improve Multimodal Therapy.

Synovial sarcoma is a translocation-associated soft-tissue malignancy that frequently affects adolescents and young adults. It is driven by one of the fusion oncoproteins SS18-SSX1, SS18-SSX2, or rarely, SS18-SSX4. Prognosis of patients with recurrent or metastatic disease is generally poor, and newer therapeutic strategies are needed. In this review, we present recent discoveries in the pathogenesis, diagnosis, and treatment of synovial sarcoma. We discuss potential therapeutic strategies to improve clinical outcomes in this disease.

Periosteal mesenchymal chondrosarcoma of the tibia with multifocal bone metastases: a case report.

Mesenchymal chondrosarcoma of bone is a rare high-grade variant of chondrosarcoma, which typically has central intramedullary location. The tumor is characterized by admixture of highly anaplastic small round malignant cells and islands of mineralized low-grade hyaline cartilage. It is most unusual for this tumor to arise on the surface of a long bone. We describe a patient with periosteal mesenchymal chondrosarcoma that arose at the surface of the right tibia with multifocal bone metastases. Radiographic, CT, MRI, and PET-CT features of this unusual tumor are presented.

The Utility of Point-of-Care Biomarkers to Detect Cardiotoxicity During Anthracycline Chemotherapy: A Feasibility Study.

BACKGROUND: Anthracycline chemotherapy is associated with an increased risk of developing heart failure (HF). The current standard for detecting HF or cardiotoxicity during chemotherapy involves episodic cardiac imaging typically at prescribed intervals and there are limited studies examining techniques beyond measuring left ventricular (LV) function. This study explores whether cardiac biomarkers troponin I (TnI) and B-type natriuretic peptide (BNP) could be part of a screening strategy for early detection of the development of cardiotoxicity in patients undergoing anthracycline chemotherapy. METHODS AND RESULTS: Patients were enrolled from a single medical center. Cardiac biomarkers (TnI, BNP) were measured before and within 24 hours after completion of anthracycline administration for each cycle of therapy. Cardiac imaging was obtained at baseline and at completion of chemotherapy (commonly at 6 or 12 months) or based on clinical suspicion of a cardiac event. Of the enrolled 109 patients, 11 (10.1%) experienced cardiac events; all of these patients had at least 1 BNP value >100 pg/mL before the cardiac event. Significant reduction in LV ejection fraction as defined for cardiotoxicity occurred in only 3 of 10 patients (30%) with a cardiac event. CONCLUSIONS: The use of cardiac biomarkers, particularly BNP, may allow early detection of cardiotoxicity related to anthracycline chemotherapy.

Prognosis of T1 synovial sarcoma depends upon surgery by oncologic surgeons.

BACKGROUND: The prognosis of early stage synovial sarcomas is not well-defined since long-term follow-up is lacking in most studies. The optimal use of surgery, radiation, and chemotherapy needs to be clarified for this group. METHODS: From 1994 to 2012, 63 patients were treated for localized synovial sarcoma with T1 (<5 cm) tumors. There were 27 males and 36 females. Mean follow-up was 85 months (range 13-210). RESULTS: At 10 years, local recurrence-free survival was 82% (95% confidence interval [CI] 67-97%), and distant recurrence-free survival was 95% (95%CI 89-100%). Two patients developed metastases after 10 years. Local recurrence was associated with lack of re-excision and treatment by non-oncologic surgeons. Microscopic residual tumor was found in 43% of re-excised specimens. Metastasis was associated with local recurrence, tumor size ≥3 cm, and treatment by non-oncologic surgeons. Radiation and chemotherapy treatment did not have a significant effect in this patient cohort. CONCLUSIONS: Early stage synovial sarcomas with T1 tumors have a relatively favorable prognosis but the potential for late relapse, and long-term follow-up beyond 10 years is recommended. Re-excision of the tumor bed and definitive treatment by trained oncologic surgeons may decrease the risk of local recurrence and metastasis. J. Surg. Oncol. 2016;114:490-494. © 2016 Wiley Periodicals, Inc.

A phase 2 trial of R1507, a monoclonal antibody to the insulin-like growth factor-1 receptor (IGF-1R), in patients with recurrent or refractory rhabdomyosarcoma, osteosarcoma, synovial sarcoma, and other soft tissue sarcomas: results of a Sarcoma Alliance for Research Through Collaboration study.

BACKGROUND: Insulin-like growth factor-1 receptor (IGF-1R) is implicated in the pathogenesis of rhabdomyosarcoma (RMS), osteosarcoma (OS), and synovial sarcoma (SS). The authors conducted a multi-institutional phase 2 trial of the monoclonal antibody R1507 in patients with various subtypes of recurrent or refractory sarcomas. METHODS: Eligibility criteria included age ≥ 2 years and a diagnosis of recurrent or refractory RMS, OS, SS, and other soft tissue sarcomas. Patients received a weekly dose of 9 mg/kg R1507 intravenously. The primary endpoint was the best objective response rate using World Health Organization criteria. Tumor imaging was performed every 6 weeks × 4 and every 12 weeks thereafter. RESULTS: From December 2007 through August 2009, 163 eligible patients from 33 institutions were enrolled. The median patient age was 31 years (range, 7-85 years). Histologic diagnoses included OS (n = 38), RMS (n = 36), SS (n = 23), and other sarcomas (n = 66). The overall objective response rate was 2.5% (95% confidence interval, 0.7%-6.2%). Partial responses were observed in 4 patients, including 2 patients with OS, 1 patient with RMS, and 1 patient with alveolar soft part sarcoma. Four additional patients (3 with RMS and 1 with myxoid liposarcoma) had a ≥ 50% decrease in tumor size that lasted for <4 weeks. The median progression-free survival was 5.7 weeks, and the median overall survival was 11 months. The most common grade 3/4 toxicities were metabolic (12%), hematologic (6%), gastrointestinal (4%), and general constitutional symptoms (8%). CONCLUSIONS: R1507 is safe and well tolerated but has limited activity in patients with recurrent or refractory bone and soft tissue sarcomas. Additional studies to help identify the predictive factors associated with clinical benefit in selected histologies such as RMS appear to be warranted.

Analysis of prognostic factors impacting oncologic outcomes after neoadjuvant tyrosine kinase inhibitor therapy for gastrointestinal stromal tumors.

BACKGROUND: Management of gastrointestinal stromal tumors (GISTs) has been transformed with tyrosine kinase inhibitors (TKIs). While data on optimal duration of adjuvant imatinib remains elusive, guidelines for administration of neoadjuvant TKIs remain unknown. METHODS: Under an institutional review board-approved protocol, patients at our institution with a diagnosis of GIST treated with neoadjuvant TKIs and surgical resection were identified. Clinical and pathologic characteristics were obtained from medical records. RESULTS: Ninety-three patients underwent surgical resection after neoadjuvant TKI therapy; 41 had primary and 52 had recurrent/metastatic GIST. Median follow-up was 2.4 years. Median duration of neoadjuvant therapy was 315 (range 3-1,611) days for primary and 537 (range 4-3,257) days for recurrent/metastatic GIST (p = 0.001). Two-year, recurrence-free survival (RFS) was 85 and 44 % for primary and recurrent/metastatic disease, respectively, whereas 2-year overall survival (OS) was 97 % for primary and 73 % for recurrent/metastatic GIST. For primary GIST, duration of neoadjuvant therapy >365 days (p = 0.02) was associated with higher risk of recurrence on univariate analysis, whereas none of the clinicopathologic factors impacted OS. For recurrent/metastatic disease, disease progression was associated with a shorter OS (p = 0.001), but no factors were found to impact RFS. Lastly, when examining all patients, KIT mutations (p = 0.03) and multivisceral resection (p = 0.011) predicted shorter RFS. CONCLUSIONS: Neoadjuvant TKIs can be effectively used for the treatment of primary and recurrent/metastatic GIST. While duration of neoadjuvant therapy, KIT mutation status, and the need for multivisceral resection can help to predict higher risk for recurrence, progression on neoadjuvant TKIs can aid in selection of patients with recurrent/metastatic disease for surgical resection.

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.

Epidemiological trends of synovial sarcoma by primary tumor sites in the US from 2000 to 2020.

BACKGROUND: Synovial sarcoma (SS) is a rare soft-tissue cancer. Existing literature encompasses Surveillance, Epidemiology, and End Results (SEER) data-based research on SS explaining the incidence-prevalence in general, by subtypes, and by age at diagnosis. Therefore, this study aimed to fill in the gap of knowledge about measures of disease occurrence and burden of SS by tumor site using the SEER database. METHODS: In this cross-sectional study, primary SS patients were selected from SEER 17 Registries, Nov. 2021 (2000-2020) using ICD-O-3 codes 9040, 9041, 9042, and 9043. Patients with additional cancers were excluded. The primary tumor site was categorized into (1) head/neck, (2) internal thorax, (3) abdomen/pelvis, (4) upper extremity, and (5) lower extremity using ICD-10CM codes. Five outcomes were analyzed: age-adjusted incidence rate, 5-year limited-duration prevalence rate, incidence-based mortality, case-fatality rate, and overall survival. RESULTS: From 2000-2020, the overall age-adjusted incidence rate was 0.15 per 100,000; the 5-year limited duration prevalence rate was 0.56 per 100,000; and the incidence-based mortality rate was 0.06 per 100,000 people. The case-fatality and 5-year OS rates were 39.2 % and 62.9 %, respectively. Lower extremity had the highest incidence of 0.07 (estimated 1166 cases), prevalence of 0.36 (estimated 224 cases), and mortality rate of 0.025 (estimated 429 deaths) per 100,000. The other four locations had much closer rates with each other. Intrathoracic SS had the highest case-fatality rate of 71.5 % (148/207) and lowest 5-year OS of 26.0 % (95 % CI: 19.6 %, 32.9 %) than other sites. CONCLUSION: Based on the measures of disease frequency, the most common primary tumor site is the lower extremity, followed by the upper extremity, abdomen/pelvis, internal thorax, and head/neck. The least favorable primary location is the internal thorax. Those with a primary location of the upper extremity have the longest overall survival, followed by the head/neck, lower extremity, abdomen/pelvis, and internal thorax.

SABR for Sarcoma Lung Metastases: Indications for Treatment and Guidance for Patient Selection.

PURPOSE: The lungs are the most common site of metastasis for patients with soft tissue sarcoma. SABR is commonly employed to treat lung metastases among select patients with sarcoma with limited disease burden. We sought to evaluate outcomes and patterns of failure among patients with sarcoma treated with SABR for their lung metastases. METHODS AND MATERIALS: We performed a retrospective review of patients treated at a tertiary cancer center between 2006 and 2020. Patient disease status at the time of SABR was categorized as either oligorecurrent or oligoprogressive. The Kaplan-Meier method was used to estimate disease outcomes. Uni- and multivariable analyses were conducted using the Cox proportional hazards model. RESULTS: We identified 70 patients with soft tissue sarcoma treated with SABR to 98 metastatic lung lesions. Local recurrence-free survival after SABR treatment was 83% at 2 years. On univariable analysis, receipt of comprehensive SABR to all sites of pulmonary metastatic disease at the time of treatment was associated with improved progression-free survival (PFS; hazard ratio [HR], 0.51 [0.29-0.88]; P = .02). On multivariable analysis, only having systemic disease controlled at the time of SABR predicted improved PFS (median PFS, 14 vs 4 months; HR, 0.37 [0.20-0.69]; P = .002) and overall survival (median overall survival, 51 vs 14 months; HR, 0.17 [0.08-0.35]; P < .0001). CONCLUSIONS: SABR provides durable long-term local control for sarcoma lung metastases. The most important predictor for improved outcomes was systemic disease control. Careful consideration of these factors should help guide decisions in a multidisciplinary setting to appropriately select the optimal candidates for SABR.

Utility of Clinical Next Generation Sequencing Tests in KIT/PDGFRA/SDH Wild-Type Gastrointestinal Stromal Tumors.

Objective: The vast majority of gastrointestinal stromal tumors (GISTs) are driven by activating mutations in KIT, PDGFRA, or components of the succinate dehydrogenase (SDH) complex (SDHA, SDHB, SDHC, and SDHD genes). A small fraction of GISTs lack alterations in KIT, PDGFRA, and SDH. We aimed to further characterize the clinical and genomic characteristics of these so-called "triple-negative" GISTs. Methods: We extracted clinical and genomic data from patients seen at MD Anderson Cancer Center with a diagnosis of GIST and available clinical next generation sequencing data to identify "triple-negative" patients. Results: Of the 20 patients identified, 11 (55.0%) had gastric, 8 (40.0%) had small intestinal, and 1 (5.0%) had rectal primary sites. In total, 18 patients (90.0%) eventually developed recurrent or metastatic disease, and 8 of these presented with de novo metastatic disease. For the 13 patients with evaluable response to imatinib (e.g., neoadjuvant treatment or for recurrent/metastatic disease), the median PFS with imatinib was 4.4 months (range 0.5-191.8 months). Outcomes varied widely, as some patients rapidly developed progressive disease while others had more indolent disease. Regarding potential genomic drivers, four patients were found to have alterations in the RAS/RAF/MAPK pathway: two with a BRAF V600E mutation and two with NF1 loss-of-function (LOF) mutations (one deletion and one splice site mutation). In addition, we identified two with TP53 LOF mutations, one with NTRK3 fusion (ETV6-NTRK3), one with PTEN deletion, one with FGFR1 gain-of-function (GOF) mutation (K654E), one with CHEK2 LOF mutation (T367fs*), one with Aurora kinase A fusion (AURKA-CSTF1), and one with FANCA deletion. Patients had better responses with molecularly targeted therapies than with imatinib. Conclusions: Triple-negative GISTs comprise a diverse cohort with different driver mutations. Compared to KIT/PDGFRA-mutant GIST, limited benefit was observed with imatinib in triple-negative GIST. In depth molecular profiling can be helpful in identifying driver mutations and guiding therapy.

High-Grade Pleomorphic Sarcomas Treated with Immune Checkpoint Blockade: The MD Anderson Cancer Center Experience.

BACKGROUND: Undifferentiated pleomorphic sarcomas (UPSs) are amongst the most common subtypes of soft-tissue sarcomas. Few real-world data on the use of immune checkpoint blockade (ICB) in UPS patients and other high-grade pleomorphic STS patients are available. PURPOSE: The purpose of our study is to describe the efficacy and toxicity of ICB in patients with advanced UPSs and other high-grade pleomorphic sarcomas treated at our institution. METHODS: This is a retrospective, observational study of all patients with metastatic high-grade pleomorphic sarcomas treated with FDA-approved ICB at MD Anderson Cancer Center between 1 January 2015 and 1 January 2023. Patients included in trials for which results are not yet published were excluded. RESULTS: Thirty-six patients with advanced/metastatic pleomorphic sarcomas were included. The median age was 52 years. A total of 26 patients (72%) had UPSs and 10 patients (28%) had other high-grade pleomorphic sarcomas. The median follow-up time was 8.8 months. The median PFS was 2.9 months. The 3-month PFS and 6-month PFS were 46% and 32%, respectively. The median OS was 12.9 months. The 12-month OS and 24-month OS were 53% and 29%, respectively. The best response, previous RT, and type of ICB treatment were significantly and independently associated with shorter PFS (p = 0.0012, p = 0.0019 and p = 0.036, respectively). No new safety signal was identified, and the toxicity was overall manageable with no toxic deaths and only four patients (11%) stopping treatment due to toxicity. CONCLUSIONS: Real-world retrospective data are consistent with the published literature, with a promising 6-month PFS of 32%. Partial or stable responders to ICB treatment have significantly improved PFS compared to progressors.

Adjuvant therapy for high-grade, uterus-limited leiomyosarcoma: results of a phase 2 trial (SARC 005).

BACKGROUND: Between 30% and 50% of women who have high-grade uterine leiomyosarcoma (uLMS) limited to the uterus at diagnosis remain progression-free at 2 years. Adjuvant pelvic radiation does not improve outcome. The objective of the current study was to determine the 2-year and 3-year progression-free survival (PFS) among a prospective cohort of women who received adjuvant gemcitabine plus docetaxel followed by doxorubicin. METHODS: Women with uterus-limited, high-grade uLMS and adequate organ function were eligible. Within 12 weeks of complete resection and after confirmation that they had no evidence of disease on computed tomography (CT) images, the patients received 4 cycles of fixed-dose-rate gemcitabine plus docetaxel. Those who were confirmed disease-free on CT scans after cycle 4 received 4 cycles of doxorubicin. CT imaging for recurrence was performed every 3 months for 2 years, then every 6 months for 3 years. RESULTS: In total, 47 women were enrolled (46 evaluable) in 3 years. Characteristics included a median age of 53 years; 1988 International Federation of Gynecology and Obstetrics stage I disease in 81% of patients, stage II disease in 15%, and serosa-only stage IIIA disease in 4%; American Joint Committee on Cancer stage II disease in 13% of patients and stage III disease in 87%; a median tumor size of 8 cm (range, 2.5-30 cm); and a median mitotic rate of 18 mitoses per 10 high-power fields (range, 5-83 mitoses per 10 high-power fields). At a median follow-up of 39.8 months, 21 of 46 patients developed recurrent disease (45.7%). The median time to recurrence was 27.4 months (range, 3-40 months). Seventy-eight percent of patients (95% confidence interval, 67%-91%) were progression-free at 2 years, and 57% (95% confidence interval, 44%-74%) were progression-free at 3 years. The median PFS was not reached and exceeded 36 months. CONCLUSIONS: Among women with high-grade, uterus-limited uLMS who received treatment with adjuvant gemcitabine plus docetaxel followed by doxorubicin, 78% remained progression-free at 2 years, and 57% remained progression-free at 3 years. A randomized trial of adjuvant chemotherapy versus observation to determine whether adjuvant chemotherapy can improve survival in women with uterus-limited uLMS is underway.

Solitary fibrous tumor: a clinicopathological study of 110 cases and proposed risk assessment model.

Solitary fibrous tumor represents a spectrum of mesenchymal tumors, encompassing tumors previously termed hemangiopericytoma, which are classified as having intermediate biological potential (rarely metastasizing) in the 2002 World Health Organization classification scheme. Few series have reported on clinicopathological predictors with outcome data and formal statistical analysis in a large series of primary tumors as a single unified entity. Institutional pathology records were reviewed to identify primary solitary fibrous tumor cases, and histological sections and clinical records reviewed for canonical prognostic indicators, including patient age, tumor size, mitotic index, tumor cellularity, nuclear pleomorphism, and tumor necrosis. Patients (n=103) with resected primary solitary fibrous tumor were identified (excluding meningeal tumors). The most common sites of occurrence were abdomen and pleura; these tumors were larger than those occurring in the extremities, head and neck or trunk, but did not demonstrate significant outcome differences. Overall 5- and 10-year metastasis-free rates were 74 and 55%, respectively, while 5- and 10-year disease-specific survival rates were 89 and 73%. Patient age, tumor size, and mitotic index predicted both time to metastasis and disease-specific mortality, while necrosis predicted metastasis only. A risk stratification model based on age, size, and mitotic index clearly delineated patients at high risk for poor outcomes. While small tumors with low mitotic rates are highly unlikely to metastasize, large tumors ≥ 15 cm, which occur in patients ≥ 55 years, with mitotic figures ≥ 4/10 high-power fields require close follow-up and have a high risk of both metastasis and death.