Controversies in orthopaedic oncology

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

Clinical recommendations for treatment of localized angiosarcoma: A consensus paper by the Italian Sarcoma Group

Angiosarcoma (AS) represents a rare and aggressive vascular sarcoma, posing distinct challenges in clinical management compared to other sarcomas. While the current European Society of Medical Oncology (ESMO) clinical practice guidelines for sarcoma treatment are applicable to AS, its unique aggressiveness and diverse tumor presentations necessitate dedicated and detailed clinical recommendations, which are currently lacking. Notably, considerations regarding surgical extent, radiation therapy (RT), and neoadjuvant/adjuvant chemotherapy vary significantly in localized disease, depending on each different site of onset. Indeed, AS are one of the sarcoma types most sensitive to cytotoxic chemotherapy. Despite this, uncertainties persist regarding optimal management across different clinical presentations, highlighting the need for further investigation through clinical trials. The Italian Sarcoma Group (ISG) organized a consensus meeting on April 1st, 2023, in Castel San Pietro, Italy, bringing together Italian sarcoma experts from several disciplines and patient representatives from "Sofia nel Cuore Onlus" and the ISG patient advocacy working group. The objective was to develop specific clinical recommendations for managing localized AS within the existing framework of sarcoma clinical practice guidelines, accounting for potential practice variations among ISG institutions. The aim was to try to standardize and harmonize clinical practices, or at least highlight the open questions in the local management of the disease, to define the best evidence-based practice for the optimal approach of localized AS and generate the recommendations presented herein.

Neoadjuvant Chemotherapy in High-Grade Myxoid Liposarcoma: Results of the Expanded Cohort of a Randomized Trial From Italian (ISG), Spanish (GEIS), French (FSG), and Polish Sarcoma Groups (PSG)

PURPOSE

A randomized trial was conducted to compare neoadjuvant standard (S) anthracycline + ifosfamide (AI) regimen with histology-tailored (HT) regimen in selected localized high-risk soft tissue sarcoma (STS). The results of the trial demonstrated the superiority of S in all STS histologies except for high-grade myxoid liposarcoma (HG-MLPS) where S and HT appeared to be equivalent. To further evaluate the noninferiority of HT compared with S, the HG-MLPS cohort was expanded.

PATIENTS AND METHODS

Patients had localized high-grade (cellular component >5%; size ≥5 cm; deeply seated) MLPS of extremities or trunk wall. The primary end point was disease-free survival (DFS). The secondary end point was overall survival (OS). The trial used a noninferiority Bayesian design, wherein HT would be considered not inferior to S if the posterior probability of the true hazard ratio (HR) being >1.25 was <5%.

RESULTS

From May 2011 to June 2020, 101 patients with HG-MLPS were randomly assigned, 45 to the HT arm and 56 to the S arm. The median follow-up was 66 months (IQR, 37-89). Median size was 107 mm (IQR, 84-143), 106 mm (IQR, 75-135) in the HT arm and 108 mm (IQR, 86-150) in the S arm. At 60 months, the DFS and OS probabilities were 0.86 and 0.73 (HR, 0.60 [95% CI, 0.24 to 1.46]; log-rank P = .26 for DFS) and 0.88 and 0.90 (HR, 1.20 [95% CI, 0.37 to 3.93]; log-rank P = .77 for OS) in the HT and S arms, respectively. The posterior probability of HR being >1.25 for DFS met the Bayesian monitoring cutoff of <5% (4.93%). This result confirmed the noninferiority of trabectedin to AI suggested in the original study cohort.

CONCLUSION

Trabectedin may be an alternative to standard AI in HG-MLPS of the extremities or trunk when neoadjuvant treatment is a consideration.

Active surveillance of diffuse-type tenosynovial giant cell tumors: A retrospective, multicenter cohort study

BACKGROUND

Diffuse-type tenosynovial giant cell tumor (D-TGCT) is a mono-articular, soft-tissue tumor. Although it can behave locally aggressively, D-TGCT is a non-malignant disease. This is the first study describing the natural course of D-TGCT and evaluating active surveillance as possible treatment strategy.

METHODS

This retrospective, multicenter study included therapy naïve patients with D-TGCT from eight sarcoma centers worldwide between 2000 and 2019. Patients initially managed by active surveillance following their first consultation were eligible. Data regarding the radiological and clinical course and subsequent treatments were collected.

RESULTS

Sixty-one patients with primary D-TGCT were initially managed by active surveillance. Fifty-nine patients had an MRI performed around first consultation: D-TGCT was located intra-articular in most patients (n = 56; 95 %) and extra-articular in 14 cases (24 %). At baseline, osteoarthritis was observed in 13 patients (22 %) on MRI. Most of the patients' reported symptoms: pain (n = 43; 70 %), swelling (n = 33; 54 %). Eight patients (13 %) were asymptomatic. Follow-up data were available for 58 patients; the median follow-up was 28 months. Twenty-one patients (36 %) had radiological progression after 21 months (median). Eight of 45 patients (18 %) without osteoarthritis at baseline developed osteoarthritis during follow-up. Thirty-seven patients (64 %) did not clinically deteriorate during follow-up. Finally, eighteen patients (31 %) required a subsequent treatment.

CONCLUSION

Active surveillance can be considered adequate for selected therapy naïve D-TGCT patients. Although follow-up data was limited, almost two-thirds of the patients remained progression-free, and 69 % did not need treatment during the follow-up period. However, one-fifth of patients developed secondary osteoarthritis. Prospective studies on active surveillance are warranted.

Outcome of rare primary malignant bone sarcoma treated with multimodal therapy: Results from the EUROpean Bone Over 40 Sarcoma Study (EURO-B.O.S.S.)

BACKGROUND

Rare primary malignant bone sarcomas (RPMBS) account for 5%-10% of primary high-grade bone tumors and represent a major treatment challenge. The outcome of patients with RPMBS enrolled in the EUROpean Bone Over 40 Sarcoma Study (EURO-B.O.S.S) is presented.

METHODS

Inclusion criteria were as follows: age from 41 to 65 years and a diagnosis of high-grade spindle cell, pleomorphic, or vascular RPMBS. The chemotherapy regimen included doxorubicin 60 mg/m2 , ifosfamide 9 g/m2 , and cisplatin 90 mg/m2 ; postoperative methotrexate 8 g/m2 was added in case of a poor histologic response. Version 2.0 of the Common Terminology Criteria for Adverse Events, Kaplan-Meier curves, log-rank tests, and univariate Cox regression models were used.

RESULTS

In total, 113 patients were evaluable for analysis. The median patient age was 52 years (range, 40-66 years), and 67 patients were men. Eighty-eight tumors were categorized as undifferentiated pleomorphic sarcomas (UPS), 20 were categorized as leiomyosarcomas, three were categorized as fibrosarcomas, and two were categorized as angiosarcomas. Eighty-three of 113 tumors were located in the extremities. Ninety-five of 113 patients presented with no evidence of metastases. After a median follow-up of 6.8 years (interquartile range [IQR], 3.5-9.8 years), the 5-year overall survival rate for patients with localized disease was 68.4% (IQR, 56.9%-77.5%), and it was 71.7% (IQR, 58.1%-81.6%) for patients with UPS and 54.9% (IQR, 29.5%-74.5%) for patients with leiomyosarcoma. Grade III-IV hematologic toxicity was reported in 81% patients; 23% had grade II-III neurotoxicity, and 37.5% had grade I-II nephrotoxicity. Five-year overall survival was significantly better for patients with localized disease, for patients who obtained surgical complete remission, and when the primary tumor was located in the extremities.

CONCLUSIONS

The survival of patients who had RPMBS in the current series was similar to that of age-matched patients who had high-grade osteosarcoma treated according to the same protocol. An osteosarcoma-like chemotherapy may be proposed in patients who have RPMBS.

Imaging Features of Alveolar Soft Part Sarcoma: Single Institution Experience and Literature Review

Alveolar soft part sarcoma (ASPS) is an extremely rare and aggressive soft-tissue sarcoma (STS) subtype with poor prognosis and limited response to radiation therapy and chemotherapy. Prompt recognition and referral to sarcoma centers for appropriate management are crucial for patients' survival. The purpose of this study was to report ASPS pre-treatment imaging features and to examine the existing literature on this topic. Twelve patients (7 women, 5 men-mean age 27.1 ± 10.7 years) were included from our single-center experience. Ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) available were reviewed according to an analysis grid incorporating features from the latest research on STS. Clinical, histological, and outcome data were collected. MRI was available in 10 patients (83.3%), US in 7 patients (58.3%), and CT in 3 patients (25%). Mean longest tumor diameter was 7.6 ± 2.9 cm, and all tumors were deeply seated. Large peritumoral feeding vessels were systematically found and identified on ultrasonography (7/7), MRI (10/10), and CT (3/3). US revealed a well-defined heterogeneous hypoechoic pattern, with abundant flow signals in all patients (7/7). In all patients, MRI showed mildly high signal intensity (SI) on T1-WI and high SI on T2-WI and peritumoral edema. Moreover, flow-voids (due to arteriosus high-flow) into the peritumoral/intratumoral feeding vessels were detected in the MRI fluid-sensitive sequences of all patients. At baseline, whole-body contrast-enhanced CT revealed metastases in 8/12 (66.7%) patients. A pre-treatment longest diameter > 5 cm was significantly associated with distant metastases at diagnosis (p = 0.01). A maximum diameter > 5 cm represents a risk of metastatic disease at diagnosis (odds ratio = 45.0000 (95% CI: 1.4908-1358.3585), p = 0.0285). In the comprehensive literature review, we found 14 articles (case series or original research) focusing on ASPS imaging, with a total of 151 patients included. Merging our experience with the data from the existing literature, we conclude that the hallmark of ASPS imaging at presentation are the following characteristics: deep location, a slight hyperintense MRI SI on T1-WI and a hyperintense SI on T2-WI, numerous MRI flow voids, high internal vascularization, and large peritumoral feeding vessels.

A systematic review of recent phase-II trials in refractory or recurrent osteosarcoma: Can we inform future trial design?

BACKGROUND/OBJECTIVE

To analyze changes in recurrent/refractory osteosarcoma phase II trials over time to inform future trials in this population with poor prognosis.

METHODS

A systematic review of trials registered on trial registries between 01/01/2017-14/02/2022. Comparison of 98 trials identified between 2003 and 2016. Publication search/analysis for both periods, last update on 01/12/2022.

RESULTS

Between 2017 and 2022, 71 phase-II trials met our selection criteria (19 osteosarcoma-specific trials, 14 solid tumor trials with and 38 trials without an osteosarcoma-specific stratum). The trial number increased over time: 13.9 versus 7 trials/year (p = 0.06). Monotherapy remained the predominant treatment (62% vs. 62%, p = 1). Targeted therapies were increasingly evaluated (66% vs. 41%, P = 0.001). Heterogeneity persisted in the trial characteristics. The inclusion criteria were measurable disease (75%), evaluable disease (14%), and surgical remission (11%). 82% of the trials included pediatric or adolescent patients. Biomarker-driven trials accounted for 25% of the total trials. The survival endpoint use (rather than response) slightly increased (40% versus 31%), but the study H1/H0 hypotheses remained heterogeneous. Single-arm designs predominated over multiarm trials (n = 7). Available efficacy data on 1361 osteosarcoma patients in 58 trials remained disappointing, even though 21% of these trials were considered positive, predominantly those evaluating multi-targeted kinase inhibitors.

CONCLUSION

Despite observed changes in trial design and an increased number of trials investigating new therapies, high heterogeneity remained with respect to patient selection, study design, primary endpoints, and statistical hypotheses in recently registered phase II trials for osteosarcoma. Continued optimization of trial design informed by a deeper biological understanding should strengthen the development of new therapies.

Transcriptomic subtyping of malignant peripheral nerve sheath tumours highlights immune signatures, genomic profiles, patient survival and therapeutic targets

BACKGROUND

Malignant peripheral nerve sheath tumour (MPNST) is an aggressive orphan disease commonly affecting adolescents or young adults. Current knowledge of molecular tumour biology has been insufficient for development of rational treatment strategies. We aimed to discover molecular subtypes of potential clinical relevance.

METHODS

Fresh frozen samples of MPNSTs (n = 94) and benign neurofibromas (n = 28) from 115 patients in a European multicentre study were analysed by DNA copy number and/or transcriptomic profiling. Unsupervised transcriptomic subtyping was performed and the subtypes characterized for genomic aberrations, clinicopathological associations and patient survival.

FINDINGS

MPNSTs were classified into two transcriptomic subtypes defined primarily by immune signatures and proliferative processes. "Immune active" MPNSTs (44%) had sustained immune signals relative to neurofibromas, were more frequently low-grade (P = 0.01) and had favourable prognostic associations in a multivariable model of disease-specific survival with clinicopathological factors (hazard ratio 0.25, P = 0.003). "Immune deficient" MPNSTs were more aggressive and characterized by proliferative signatures, high genomic complexity, aberrant TP53 and PRC2 loss, as well as high relative expression of several potential actionable targets (EGFR, ERBB2, EZH2, KIF11, PLK1, RRM2). Integrated gene-wise analyses suggested a DNA copy number-basis for proliferative transcriptomic signatures in particular, and the tumour copy number burden further stratified the transcriptomic subtypes according to patient prognosis (P < 0.01).

INTERPRETATION

Approximately half of MPNSTs belong to an "immune deficient" transcriptomic subtype associated with an aggressive disease course, PRC2 loss and expression of several potential therapeutic targets, providing a rationale for molecularly-guided intervention trials.

FUNDING

Research grants from non-profit organizations, as stated in the Acknowledgements.

NTRK rearranged sarcoma of the bone. Role for larotrectinib in the neoadjuvant setting of an ultra-rare tumor: a case report

BACKGROUND

Neurotrophic tyrosine receptor kinase (NTRK) gene-fusion targeted molecules revolutionized the paradigm of treatment of a limited subgroup of cancers of various histologies. Entrectinib and larotrectinib obtained unprecedented response rates in patients with cancer harboring NTRK rearrangements. This evidence recently led to the agnostic approval of these drugs, and evidence (confirmation) of their activity in a broader disease setting is emerging. Here, we report the case of a patient affected by EML4-NTRK3 rearranged undifferentiated spindle cell bone sarcoma treated with larotrectinib, and we argue (discuss about) the incidence and clinical presentation of NTRK gene-fusion positive bone sarcomas, the potential use of upfront treatment with NTRK inhibitors in neoadjuvant setting, and the role of a multidisciplinary tumor board. Despite the rarity of these rearrangements in patients with primitive bone sarcomas, the therapy with NTRK inhibitors represents a highly effective strategy to be pursued in selected cases even in neoadjuvant settings. The management of these very rare cancers should always be discussed in a multidisciplinary board of reference centers.

IDH mutations in G2-3 conventional central bone chondrosarcoma: a mono institutional experience

BACKGROUND

Heterozygous isocitrate dehydrogenase (IDH) mutations occur in about half of conventional central bone chondrosarcomas (CCBC). Aim of this study was to assess the frequency and prognostic impact of IDH mutations in high grade CCBC patients.

METHODS

64 patients with G2 and G3 CCBC were included. DNA extraction, PCR amplification of IDH1/2 exon 4s, and sequencing analysis with Sanger were performed.

RESULTS

IDH mutations were detected in 24/54 patients (44%): IDH1 in 18, IDH2 in 4, and both IDH1/2 in 2 patients. The frequency of mutations was 37% in G2 vs. 69% in G3 (p = 0.039), and 100% in three Ollier disease associated chondrosarcoma. 5-year overall survival (OS) at 124 months (range 1-166) was 51%, with no significant difference based on the IDH mutational status: 61% in IDHmut vs. 44% in IDH wild type (IDHwt). The 5-year relapse free survival (RFS) was 33% (95% CI:10-57) for IDHmut vs. 57% (95%CI: 30-77) for IDHwt. Progression free survival (PFS) was 25% (95%CI:1-65) IDHmut vs. 16% (95%CI: 0.7-52) IDHwt. 55% (5/9) of IDHmut G2 became higher grade at the recurrence, as compared with 25% (3/12) of G2 IDHwt.

CONCLUSIONS

This study shows a higher frequency of IDH mutations in G3 CCBC as compared with G2. No significant differences in OS, RFS, and PFS by mutational status were detected. After relapse, a higher rate of G3 for IDH mutated CCBC was observed.

Tenosynovial Giant Cell Tumor Observational Platform Project (TOPP) Registry: A 2-Year Analysis of Patient-Reported Outcomes and Treatment Strategies

BACKGROUND

The Tenosynovial giant cell tumor Observational Platform Project (TOPP) registry is an international prospective study that -previously described the impact of diffuse-type tenosynovial giant cell tumour (D-TGCT) on patient-reported outcomes (PROs) from a baseline snapshot. This analysis describes the impact of D-TGCT at 2-year follow-up based on treatment strategies.

MATERIAL AND METHODS

TOPP was conducted at 12 sites (EU: 10; US: 2). Captured PRO measurements assessed at baseline, 1-year, and 2-year follow-ups were Brief Pain Inventory (BPI), Pain Interference, BPI Pain Severity, Worst Pain, EQ-5D-5L, Worst Stiffness, and -Patient-Reported Outcomes Measurement Information System. Treatment interventions were no current/planned treatment (Off-Treatment) and systemic treatment/surgery (On-Treatment).

RESULTS

A total of 176 patients (mean age: 43.5 years) were included in the full analysis set. For patients without active treatment strategy -(Off-Treatment) at baseline (n = 79), BPI Pain Interference (1.00 vs. 2.86) and BPI Pain Severity scores (1.50 vs. 3.00) were numerically favorable in patients remaining Off-Treatment compared with those who switched to an active treatment strategy at year 1. From 1-year to 2-year -follow-ups, patients who remained Off-Treatment had better BPI Pain Interference (0.57 vs. 2.57) and Worst Pain (2.0 vs. 4.5) scores compared with patients who switched to an alternative treatment strategy. In addition, EQ-5D VAS scores (80.0 vs. 65.0) were higher in patients who remained -Off-Treatment between 1-year and 2-year follow-ups compared with patients who changed treatment strategy. For patients receiving systemic treatment at baseline, numerically favorable scores were seen in patients remaining on systemic therapy at 1-year follow-up: BPI Pain Interference (2.79 vs. 5.93), BPI Pain Severity (3.63 vs. 6.38), Worst Pain (4.5 vs. 7.5), and Worst Stiffness (4.0 vs. 7.5). From 1-year to 2-year follow-up, EQ-5D VAS scores (77.5 vs. 65.0) were higher in patients who changed from systemic treatment to a different treatment strategy.

CONCLUSION

These findings highlight the impact D-TGCT has on patient quality of life, and how treatment strategies may be influenced by these outcome measures. (ClinicalTrials.gov number: NCT02948088).

A global collaboRAtive study of CIC-rearranged, BCOR::CCNB3-rearranged and other ultra-rare unclassified undifferentiated small round cell sarcomas (GRACefUl)

BACKGROUND

Undifferentiated small round cell sarcomas (URCSs) represent a diagnostic challenge, and their optimal treatment is unknown. We aimed to define the clinical characteristics, treatment, and outcome of URCS patients.

METHODS

URCS patients treated from 1983 to 2019 at 21 worldwide sarcoma reference centres were retrospectively identified. Based on molecular assessment, cases were classified as follows: (1) CIC-rearranged round cell sarcomas, (2) BCOR::CCNB3-rearranged round cell sarcomas, (3) unclassified URCSs. Treatment, prognostic factors and outcome were reviewed.

RESULTS

In total, 148 patients were identified [88/148 (60%) CIC-rearranged sarcoma (median age 32 years, range 7-78), 33/148 (22%) BCOR::CCNB3-rearranged (median age 17 years, range 5-91), and 27/148 (18%) unclassified URCSs (median age 37 years, range 4-70)]. One hundred-one (68.2%) cases presented with localised disease; 47 (31.8%) had metastases at diagnosis. Male prevalence, younger age, bone primary site, and a low rate of synchronous metastases were observed in BCOR::CCNB3-rearranged cases. Local treatment was surgery in 67/148 (45%) patients, and surgery + radiotherapy in 52/148 (35%). Chemotherapy was given to 122/148 (82%) patients. At a 42.7-month median follow-up, the 3-year overall survival (OS) was 92.2% (95% CI 71.5-98.0) in BCOR::CCNB3 patients, 39.6% (95% CI 27.7-51.3) in CIC-rearranged sarcomas, and 78.7% in unclassified URCSs (95% CI 56.1-90.6; p < 0.0001).

CONCLUSIONS

This study is the largest conducted in URCS and confirms major differences in outcomes between URCS subtypes. A full molecular assessment should be undertaken when a diagnosis of URCS is suspected. Prospective studies are needed to better define the optimal treatment strategy in each URCS subtype.

Nirogacestat, a γ-Secretase Inhibitor for Desmoid Tumors

BACKGROUND

Desmoid tumors are rare, locally aggressive, highly recurrent soft-tissue tumors without approved treatments.

METHODS

We conducted a phase 3, international, double-blind, randomized, placebo-controlled trial of nirogacestat in adults with progressing desmoid tumors according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Patients were assigned in a 1:1 ratio to receive the oral γ-secretase inhibitor nirogacestat (150 mg) or placebo twice daily. The primary end point was progression-free survival.

RESULTS

From May 2019 through August 2020, a total of 70 patients were assigned to receive nirogacestat and 72 to receive placebo. Nirogacestat had a significant progression-free survival benefit over placebo (hazard ratio for disease progression or death, 0.29; 95% confidence interval, 0.15 to 0.55; P<0.001); the likelihood of being event-free at 2 years was 76% with nirogacestat and 44% with placebo. Between-group differences in progression-free survival were consistent across prespecified subgroups. The percentage of patients who had an objective response was significantly higher with nirogacestat than with placebo (41% vs. 8%; P<0.001), with a median time to response of 5.6 months and 11.1 months, respectively; the percentage of patients with a complete response was 7% and 0%, respectively. Significant between-group differences in secondary patient-reported outcomes, including pain, symptom burden, physical or role functioning, and health-related quality of life, were observed (P≤0.01). Frequent adverse events with nirogacestat included diarrhea (in 84% of the patients), nausea (in 54%), fatigue (in 51%), hypophosphatemia (in 42%), and maculopapular rash (in 32%); 95% of adverse events were of grade 1 or 2. Among women of childbearing potential receiving nirogacestat, 27 of 36 (75%) had adverse events consistent with ovarian dysfunction, which resolved in 20 women (74%).

CONCLUSIONS

Nirogacestat was associated with significant benefits with respect to progression-free survival, objective response, pain, symptom burden, physical functioning, role functioning, and health-related quality of life in adults with progressing desmoid tumors. Adverse events with nirogacestat were frequent but mostly low grade. (Funded by SpringWorks Therapeutics; DeFi ClinicalTrials.gov number, NCT03785964.).

Lung metastasectomy for osteosarcoma in children, adolescents, and young adults: proof of permanent cure

INTRODUCTION

Surgical resection of pulmonary metastases has been associated with increased survival at 5 years for osteosarcoma, but limited information is available on long-term outcome, role of repeated metastasectomies, and surgical sequelae in a pediatric population. We analyzed a consecutive series of children, adolescents, and young adults (AYA) treated by repeated lung metastasectomies during a period >40 years to estimate the clinical benefit and potential cure rate of salvage surgery.

METHODS

All patients who underwent lung metastasectomy for osteosarcoma at the IRCCS Istituto Ortopedico Rizzoli of Bologna, University of Modena, and IRCCS Istituto Nazionale Tumori of Milan from May 1973 to January 2014 were included. Overall survival (OS) at 20 years from the first metastasectomy was calculated.

RESULTS

A total of 463 consecutive children and AYA were analyzed. Median age was 15.9 years (range 0.2-23.2 years) and median follow-up 18.6 years. The 5- and 20-year OS were 34.0% and 29.7% (95% CI 25.5-34.0%). Among the 138 (29.8%) alive patients, 42 (30.4%) had disease recurrence cured by repeated metastasectomies. Disease-free interval from primary tumor, number of metastases, and complete resection were the most relevant survival predictors at multivariable model analysis.

DISCUSSION

The extended follow-up of this consecutive series shows that repeated lung metastasectomy can achieve a permanent cure when offered to properly selected patients with metastases from osteosarcoma.

Best clinical management of tenosynovial giant cell tumour (TGCT): A consensus paper from the community of experts

Tenosynovial giant cell tumour (TGCT) is a rare, locally aggressive, mesenchymal tumor arising from the joints, bursa and tendon sheaths. TGCT comprises a nodular- and a diffuse-type, with the former exhibiting mostly indolent course and the latter a locally aggressive behavior. Although usually not life-threatening, TGCT may cause chronic pain and adversely impact function and quality of life (QoL). CSFR1 inhibitors are effective with benefit on symptoms and QoL but are not available in most countries. The degree of uncertainty in selecting the most appropriate therapy and the lack of guidelines on the clinical management of TGCT make the adoption of new treatments inconsistent across the world, with suboptimal outcomes for patients. A global consensus meeting was organized in June 2022, involving experts from several disciplines and patient representatives from SPAGN to define the best evidence-based practice for the optimal approach to TGCT and generate the recommendations presented herein.

Pexidartinib Provides Modest Pain Relief in Patients With Tenosynovial Giant Cell Tumor: Results From ENLIVEN

BACKGROUND

The double-blind, randomized, placebo-controlled phase 3 study of orally administered PLX3397 in patients with pigmented villonodular synovitis or giant cell tumor of the tendon sheath (ENLIVEN) showed that pexidartinib provides a robust objective tumor response in adults with tenosynovial giant cell tumors (TGCT) not amenable to improvement with surgery. Based on these results, in 2019, pexidartinib received accelerated approval in the United States in this population as a breakthrough therapy under an orphan drug designation. However, the ability of pexidartinib to relieve pain in ENLIVEN was not fully detailed, and the relationship between pain relief and objective tumor response was not described.

QUESTIONS/PURPOSES

(1) What level of pain relief was achieved by pexidartinib treatment in ENLIVEN? (2) How was pain relief related to objective tumor responses? (3) How durable was pain relief?

METHODS

The current study included planned primary and exploratory assessments of patient-assessed worst pain at the site of the tumor in the ENLIVEN trial. ENLIVEN was a phase 3 randomized, placebo-controlled clinical trial in which adults with TGCT not amenable to improvement with surgery received pexidartinib or placebo for 24 weeks, after which eligible patients could receive open-label pexidartinib. Of 174 patients assessed for eligibility, 121 were randomized (50% [60] to placebo, 50% [61] to pexidartinib), and 120 were given either placebo or pexidartinib (59 received placebo and 61 received pexidartinib) and were included in an intent-to-treat analysis. Fifty-nine percent (71 of 120) of the overall treated population was female, and 88% (106 of 120) were White. Mean age was 45 ± 13 years. Tumors were mostly in the lower extremities (92% [110 of 120]), most commonly in the knee (61% [73 of 120]) and ankle (18% [21 of 120]). As a secondary outcome, patients scored worst pain at the site of the tumor in the past 24 hours on an 11-point numeric rating scale (NRS). The primary definition of a pain response was a decrease of at least 30% in the weekly mean worst-pain NRS score and increase of less than 30% in narcotic analgesic use between baseline and week 25. Planned exploratory assessments of pain included the frequency of a pain response using alternative thresholds, including a decrease in worst-pain NRS score of 50% or more and a decrease of at least 2 points (minimum clinically important difference [MCID]), the magnitude of pain reduction between baseline and week 25, correlation between worst-pain NRS score and tumor shrinkage by RECIST 1.1 criteria, and the durability of the pain response during the open-label extension. Pain responses during the randomized portion of the trial were compared according to intention-to-treat analysis, with a one-sided threshold of p < 0.025 to reduce the risk of false-positive results. Pain assessment was complete for 59% (35 of 59) of patients in the placebo group and 54% (33 of 61) of patients in the pexidartinib group. Demographic and disease characteristics did not differ between the two treatment groups.

RESULTS

A difference in the primary assessment of a pain response was not detected between pexidartinib and placebo (response percentage 31% [19 of 61] [95% CI 21% to 44%] versus 15% [9 of 59] [95% CI 8% to 27%]; one-sided p = 0.03). In the exploratory analyses, pexidartinib provided a modest improvement in pain (response percentage 26% [16 of 61] [95% CI 17% to 38%] versus 10% [6 of 59] [95% CI 5% to 20%]; one-sided p = 0.02 using the 50% threshold and 31% [19 of 61] [95% CI 21% to 44%] versus 14% [8 of 59] [95% CI 7% to 25%]; one-sided p = 0.02 using the MCID threshold). The least-squares mean change in the weekly mean worst-pain NRS score between baseline and week 25 was larger in patients treated with pexidartinib than placebo (-2.5 [95% CI -3.0 to -1.9] versus -0.3 [95% CI -0.9 to 0.3]; p < 0.001), although the mean difference between the two groups (-2.2 [95% CI -3.0 to -1.4]) was just over the MCID. Improvement in the weekly mean worst-pain NRS score correlated with the reduction in tumor size (r = 0.44; p < 0.001) and tumor volume score (r = 0.61; p < 0.001). For patients in the open-label extension, the change in the worst-pain NRS score from baseline was similar to the change at the end of the randomized portion and just above the MCID (mean -2.7 ± 2.2 after 25 weeks and -3.3 ± 1.7 after 50 weeks of receiving pexidartinib).

CONCLUSION

Based on the current study, a modest reduction in pain, just larger than the MCID, may be an added benefit of pexidartinib in these patients, although the findings are insufficient to justify the routine use of pexidartinib for pain relief.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Transcription regulators and ultra-rare and other rare translocation-related sarcomas treated with trabectedin: A proof of principle from a post-hoc analysis

Background

Among sarcomas, which are rare cancers with an incidence of <6 per 100.000/year cases, ultra-rare sarcomas have an incidence of approximately ≤1/1,000,000/year cases and altogether account for ~20% of all soft tissue sarcomas (STS) and bone sarcomas. The Italian Sarcoma Group has recently performed a non-interventional, retrospective TrObs study with data from 512 anthracycline-pretreated patients with advanced multiple STS histologies and treated with trabectedin (Palmerini, Cancers 2021; ClinicalTrials.gov Identifier: NCT02793050).

Methods

A post-hoc analysis of case series to evaluate the efficacy and safety of trabectedin on patients with ultra-rare and other rare translocation-related sarcomas included in TrObs study was performed. Main outcomes comprised investigator-assessed overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and safety.

Results

Thirty-six patients (18 women) with ultra-rare and other rare sarcoma and a median age of 53.0 years (range: 22-81) were included. Most patients had solitary fibrous tumor (SFT; n=11) followed by epithelioid sarcoma (n=5), malignant peripheral nerve sheath tumor (MPNST; n=4), extraskeletal myxoid chondrosarcoma (EMC; n=3), desmoplastic small round cell tumor (DSRCT; n=3), and alveolar soft part sarcoma (ASPS), rhabdomyosarcoma and clear cell sarcoma (n=2 each). Thirty-five patients had metastatic disease and 23 patients received trabectedin as a second-line treatment. Among 35 patients evaluable for response, two patients with SFT and ASPS had a partial response and one patient with DSRCT obtained a complete response, reaching an ORR of 8.6% (95% CI: 2.8-23.4%). Among patients with an ORR, 6-months PFS was 100% in patients with ASPS, 45.7% in patients with SFT and 33.3% in those with DSRCT. Two patients with epithelioid sarcoma and myoepithelioma had disease stabilization lasting >24 months. Nine patients had at least one grade 3/4 adverse event, mostly being bone marrow toxicity (n=6).

Conclusions

Trabectedin has some anti-tumor activity in some ultra-rare and other rare sarcomas, particularly translocation-related sarcomas, with the well-known manageable safety profile.

A prospective real-world study of the diffuse-type tenosynovial giant cell tumor patient journey: A 2-year observational analysis

BACKGROUND AND OBJECTIVES

Diffuse-tenosynovial giant cell tumor (D-TGCT) is a rare, locally aggressive, typically benign neoplasm affecting mainly large joints, representing a wide clinical spectrum. We provide a picture of the treatment journey of D-TGCT patients as a 2-year observational follow-up.

METHODS

The TGCT Observational Platform Project registry was a multinational, multicenter, prospective observational study at tertiary sarcoma centers spanning seven European countries and two US sites. Histologically confirmed D-TGCT patients were categorized as either those who remained on initial treatment strategy (determined at baseline visit) or those who changed treatment strategy with specific changes documented (e.g., systemic treatment to surgery) at the 1-year and/or 2-year follow-up visits.

RESULTS

A total of 176 patients were assessed, mean diagnosis age was 38.4 (SD ± 14.6) years; most patients had a knee tumor (120/176, 68.2%). For the 2-year observation period, most patients (75.5%) remained on the baseline treatment strategy throughout, 54/79 patients (68.4%) remained no treatment, 30/45 patients (66.7%) remained systemic treatment, 39/39 patients (100%) remained surgery. Those who changed treatment strategy utilized multimodal treatment options.

CONCLUSIONS

This is the first prospectively collected analysis to describe D-TGCT patient treatments over an extended follow-up and demonstrates the need for multidisciplinary teams to determine an optimal treatment strategy.

Retrospective observational studies in ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society (CTOS) community of experts on the minimum requirements for the evaluation of activity of systemic treatments

BACKGROUND

In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS.

METHODS

Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021).

RESULTS

Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice.

CONCLUSIONS

These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.

CINSARC in high-risk soft tissue sarcoma patients treated with neoadjuvant chemotherapy: Results from the ISG-STS 1001 study

BACKGROUND

The Complexity INdex in SARComas (CINSARC) is a transcriptional signature derived from the expression of 67 genes involved in mitosis control and chromosome integrity. This study aims to assess CINSARC value of in an independent series of high-risk patients with localized soft tissue sarcoma (STS) treated with preoperative chemotherapy within a prospective, randomized, phase III study (ISG-STS 1001).

PATIENTS AND METHODS

Patients with available pre-treatment samples, treated with 3 cycles of either standard (ST) preoperative or histotype-tailored (HT) chemotherapy, were scored according to CINSARC (low-risk, C1; high-risk, C2). The 10-year overall survival probability (pr-OS) according to SARCULATOR was calculated, and patients were classified accordingly (low-risk, Sarc-LR, 10-year pr-OS>60%; high-risk, Sarc-HR, 10-year pr-OS<60%). Survival functions were estimated using the Kaplan-Meier method and compared using log-rank test.

RESULTS

Eighty-six patients were included, 30 C1 and 56 C2, 49 Sarc-LR and 37 Sarc-HR. A low level of agreement between CINSARC and SARCULATOR was observed (Cohen's Kappa = 0.174). The 5-year relapse-free survival in C1 and C2 were 0.57 and 0.55 (p = 0.481); 5-year metastases-free survival 0.63 and 0.64 (p = 0.740); 5-year OS 0.80 and 0.72 (p = 0.460). The 5-year OS in C1 treated with ST and HT chemotherapy was 0.84 and 0.76 (p = 0.251) respectively; in C2 treated it was 0.72 and 0.70 (p = 0.349). The 5-year OS in Sarc-LR treated with S and HT chemotherapy was 0.80 and 0.82 (p = 0.502) respectively; in Sarc-HR it was 0.70 and 0.61 (p = 0.233).

CONCLUSIONS

Our results, although constrained by the small size of the series, suggest that CINSARC has weak prognostic power in high-risk, localized STS treated with neoadjuvant chemotherapy.

Bone Turnover Marker (BTM) Changes after Denosumab in Giant Cell Tumors of Bone (GCTB): A Phase II Trial Correlative Study

Background: Giant cell tumors of bone (GCTB) are osteolytic tumors. Denosumab, a RANK-L inhibitor, is approved for GCTB. Data on serum bone turnover marker (sBTM) changes are lacking. We present a phase II correlative study on sBTMs in GCTB patients treated with denosumab. Methods: All GCTB patients receiving denosumab within a multicentre, open-label, phase 2 study were enrolled. Serum levels of carboxyterminal-crosslinked-telopeptide of type I collagen (s-CTX), alkaline phosphatase (ALP), bone-alkaline phosphatase (bALP), parathyroid hormone (sPTH), and osteocalcin (OCN) were prospectively assessed (baseline, T0, 3 months, T1, 6 months, T2). The primary endpoint was assessment of sBTM changes after denosumab; the secondary endpoints were disease-free survival (DFS) and sBTM correlation. Results: In 54 cases, sBTMs decreased during denosumab treatment except for sPTH. With a median follow-up of 59 months, 3-year DFS was 65% (%CI 52−79), with a significantly worse outcome for patients with high (≥500 UI/mL) s-CTX at baseline, as compared to low s-CTX (<500 UI/mL) (3-year DFS for high CTX 45% (95%CI 23−67) vs. 75% (95%CI 59−91) for low s-CTX. Higher median ALP and s-CTX were found for patients with tumor size ≥ 5 cm (p = 0.0512; p = 0.0589). Conclusion: Denosumab induces ALP/OCN and s-CTX reduction. High baseline s-CTX identifies a group of patients at higher risk of progression of the disease.

Outcomes from a mechanistic biomarker multi-arm and randomised study of liposomal MTP-PE (Mifamurtide) in metastatic and/or recurrent osteosarcoma (EuroSarc-Memos trial)

The phase III clinical study of adjuvant liposomal muramyl tripeptide (MTP-PE) in resected high-grade osteosarcoma (OS) documented positive results that have been translated into regulatory approval, supporting initial promise for innate immune therapies in OS. There remains, however, no new approved treatment such as MTP-PE for either metastatic or recurrent OS. Whilst the addition of different agents, including liposomal MTP-PE, to surgery for metastatic or recurrent high-grade osteosarcoma has tried to improve response rates, a mechanistic hiatus exists in terms of a detailed understanding the therapeutic strategies required in advanced disease. Here we report a Bayesian designed multi-arm, multi-centre, open-label phase II study with randomisation in patients with metastatic and/or recurrent OS, designed to investigate how patients with OS might respond to liposomal MTP-PE, either given alone or in combination with ifosfamide. Despite the trial closing because of poor recruitment within the allocated funding period, with no objective responses in eight patients, we report the design and feasibility outcomes for patients registered into the trial. We demonstrate the feasibility of the Bayesian design, European collaboration, tissue collection with genomic analysis and serum cytokine characterisation. Further mechanistic investigation of liposomal MTP-PE alone and in combination with other agents remains warranted in metastatic OS.

Spine high-grade osteosarcoma in the era of radiotherapy with high-energy charged particles: A single institution retrospective analysis

11532

Background: Limited are data on high-grade osteosarcoma occurring in the spine. Wide resection is recommended, but it is a difficult and high morbidity procedure in the spine. High-energy particle therapy has been recently used. The goal of this study was to examine treatment and outcome of patients with osteosarcoma in the mobile spine. Methods: Spine high grade osteosarcoma patients who underwent surgery at the Rizzoli Institute between 2009 and 2020 were identified. Treatment, outcome, and prognostic factors in patients treated in a single institution were examined. Results: Characteristics of the 20 patients (8 female; 12 male) included: median age, 39.7 years (range, 14-71 years), 5 (25%) with tumors in the cervical spine, 6 (30%) with tumors in the thoracic spine, and 9 with tumors in the lumbar spine (45%); 14 (70%) patients with localized disease and 6 (30%) with metastatic disease at the time of presentation. Nineteen patients (95%) underwent chemotherapy, the majority were treated with MAP (methotrexate, doxorubicin, cisplatin) regimen. In 12 patients undergoing preoperative chemotherapy (n = 11) or chemotherapy and radiotherapy (n = 1), the median tumor % necrosis was 20 (IQR 20 - 40), with none achieving a good histologic response (> 90%). All patients underwent surgery. Adequate surgical margins were achieved in 5 patients (25%). In patients with positive margins, radiotherapy was administered to 8 (40%) patients. Four patients with positive margins after resection received photon neoadjuvant or adjuvant therapy. Four patients received high-energy particles as adjuvant therapy after planned gross total excision. The median overall survival rate was 10.5 months (IQR 5.8 - 15.0) for patients with metastatic disease and 25.5 months (IQR 8.3 - 46.0) for patients with localized disease (P =.0501). Patients treated with planned intralesional gross total resection followed by adjuvant high-energy particle therapy had a significant higher disease-specific survival than patients with positive margins after resection with or without additional conventional radiotherapy (P =.023). Conclusions: Metastatic disease, is a poor prognostic factor for high grade osteosarcoma of the spine. Post-operative high-energy particle therapy improved overall survival in patients undergoing a planned gross total resection compared to intralesional resection in this series. Chemotherapy induced necrosis was low underscoring the need of more aggressive multidisciplinary approaches for these patients.

Prevalence of ultra-rare undifferentiated round cells sarcoma of bone and soft tissue after genomic classification

11559

Background: Over the last decade, the category of undifferentiated round cell sarcomas (URCS), defined by the absence of Ewing sarcoma-associated translocations, has emerged. Aim of this study was to assess prevalence of each entity and outcome after genomic classification. Methods: Ewing sarcoma and other URCS diagnosed between 1920 and 2020 were reviewed. All URCS with available material were analyzed with FISH, RT-qPCR and/or Archer FusionPlex Sarcoma Panel. Demographic and treatment were collected. Survival was analyzed in patients with available follow-up. Results: 1995 cases identified, 20 cases lacked material for further genetic analysis and were excluded. 1975 cases were classified as follows: 1925 Ewing sarcomas (97.47%), 25 CIC-rearranged sarcomas (1.27%), 16 BCOR-CCNB3 rearranged sarcomas (0.81%), 2 EWSR1-NFATC2 sarcoma (0.1%), one each as CIC-LEUTX and FUS-NFATC2 rearranged sarcoma (0.05% each), and 5 as unclassified URCS (0.25%). A different presentation according to tumor type was shown in 43/50 ultra-rare tumors (Table). Forty-one/50 cases had available follow-up: 20/41 patients underwent surgery, 14/41 surgery+radiotherapy, 6 radiotherapy only, and no local treatment for 1 patient. Chemotherapy was administrated to 36/41 patients (Ewing sarcoma drugs in 16/22 CIC-DUX-4 and 8/11 BCOR-CCNB3; osteosarcoma drugs in 2/11 BCOR-CCNB3, and doxorubicin/ifosfamide in 2/22 CIC-DUX4 and 2/5 URCS; not specified in 6 cases). The 3-years overall survival (OS) was 32.7%f for CIC-rearranged sarcomas (75% in localize disease, 7,7% for the advanced disease, p 0.0084), 81.8% for BCOR-CCNB3 sarcomas (87.5% localized, 66.7% advanced; p 0.0734), and 60% for URCS (p 0.057). 1 patient with CIC-LEUTX sarcoma presenting with metastases died 13 months from diagnosis, 1 patient with FUS-NFATC2 and 1 with EWSR1-NFATC2 rearrenged sarcomas were alive without disease at 8 and 5 years from onset. Conclusions: Prevalence of URCS characterized by a combination of morphologic observation ad molecular techniques is provided. The majority of the cases underwent surgery or surgery combined with radiotherapy, and Ewing-like chemotherapy. The survival difference among different entities underscores the need of accurate subclassification of round cell sarcomas. Novel drugs for CIC-DUX-4 sarcomas presenting with metastases are needed. [Table: see text]

Neoadjuvant chemotherapy in high-risk soft tissue sarcomas: Results of the expanded cohort of myxoid liposarcoma of the randomized clinical trial from the Italian Sarcoma Group (ISG), the Spanish Sarcoma Group (GEIS), the French Sarcoma Group (FSG), and the Polish Sarcoma Group (PSG)

11508

Background: An ISG, GEIS, FSG and PSG randomized trial on 3 cycles of neoadjuvant epirubicine+ifosfamide (EI) versus a histology-tailored (HT) regimen in selected localized high-risk STS showed some superiority of EI in all histologies with the exception of Myxoid Liposarcoma (MLPS) where EI and HT regimens seemed equivalent (J Clin Oncol 2020; 38:2178-86). This MLPS cohort was expanded with the aim to assess the non-inferiority of the HT regimen compared to EI. Methods: This was a multicenter European randomized trial comparing EI versus a HT regimen. Patients (pts) had localized high-risk (grade = 3; size >5 cm; deeply seated) undifferentiated pleomorphic sarcoma, leiomyosarcoma, malignant peripheral nerve sheath tumor, synovial sarcoma or MLPS of extremities or trunk wall. Primary end-point was Disease Free Survival (DFS). Secondary end-point was Overall Survival (OS). The MLPS cohort was expanded after the results of the 3rd interim analysis (Lancet Oncol 2017; 18:812-22) in order to reject the hypothesis that HT regimen trabectedin is associated with a HR of relapse = 1.25 with a non-inferiority design. To this aim, a Bayesian monitoring approach was used until the probability that the true HR is higher than 1.25 was greater than 80% or smaller than 5%. Results: From May 2011 to June 2020, 101 pts affected by high-risk MLPS were randomized, 56 to EI and 45 to HT regimen. The median follow-up was 66 months (IQ range 37-89). Median size was 107 mm (IQ range 84-143), 108 mm (IQ range 86-150) in the EI and 106 mm (IQ range75-135) in the HT arm. The DFS and OS probabilities at 60 months were 0.86 and 0.73 (HR:0.60; 95%CI: 0.24-1.46; log rank p = 0.26 for DFS) and 0.88 and 0.90 (HR:1.20; 95%CI:0.37-3.93; log rank p = 0.77 for OS), in the HT and EI arm, respectively. 5-yr observed and Sarculator-predicted OS were 0.89 (95% CI 0.82-0.97) and 0.80 in all patients (p = 0.020), 0.90 (95% CI 0.81-1.00) and 0.79 in the EI arm (p = 0.049) and 0.88 (95% CI 0.77-1.00) and 0.81 in the HT arm (p = 0.204) respectively. Conclusions: In the expanded cohort of MLPS, the HT neoadjuvant therapy trabectedin was not inferior to EI. While survival in both arms was better than predicted by Sarculator, it is left to understand whether this patient population, who had on average a lower Sarculator-predicted risk of death compared with the rest of the trial population, may benefit from a neoadjuvant therapy. Clinical trial information: NCT01710176.

SELNET clinical practice guidelines for bone sarcoma

Bone sarcoma are infrequent diseases, representing < 0.2% of all adult neoplasms. A multidisciplinary management within reference centers for sarcoma, with discussion of the diagnostic and therapeutic strategies within an expert multidisciplinary tumour board, is essential for these patients, given its heterogeneity and low frequency. This approach leads to an improvement in patient's outcome, as demonstrated in several studies. The Sarcoma European Latin-American Network (SELNET), aims to improve clinical outcome in sarcoma care, with a special focus in Latin-American countries. These Clinical Practice Guidelines (CPG) have been developed and agreed by a multidisciplinary expert group (including medical and radiation oncologist, surgical oncologist, orthopaedic surgeons, radiologist, pathologist, molecular biologist and representatives of patients advocacy groups) of the SELNET consortium, and are conceived to provide the standard approach to diagnosis, treatment and follow-up of bone sarcoma patients in the Latin-American context.

Phase 2 study for nonmetastatic extremity high-grade osteosarcoma in pediatric and adolescent and young adult patients with a risk-adapted strategy based on ABCB1/P-glycoprotein expression: An Italian Sarcoma Group trial (ISG/OS-2)

Background

According to retrospective osteosarcoma series, ABCB1/P‐glycoprotein (Pgp) overexpression predicts for poor outcomes. A prospective trial to assess a risk‐adapted treatment strategy using mifamurtide in Pgp+ patients was performed.

Methods

This was a phase 2, multicenter, uncontrolled trial including patients 40 years old or younger with nonmetastatic extremity high‐grade osteosarcoma stratified according to Pgp expression. All patients received high‐dose methotrexate, doxorubicin, and cisplatin (MAP) preoperatively. In Pgp+ patients, mifamurtide was added postoperatively and combined with MAP for a good histologic response (necrosis ≥ 90%; good responders [GRs]) or with high‐dose ifosfamide (HDIFO) at 3 g/m²/d on days 1 to 5 for a histologic response < 90% (poor responders [PRs]). Pgp– patients received MAP postoperatively. After an amendment, the cumulative dose of methotrexate was increased from 60 to 120 g/m² (from 5 to 10 courses). The primary end point was event‐free survival (EFS). A postamendment analysis was performed.

Results

In all, 279 patients were recruited, and 194 were included in the postamendment analysis: 70 (36%) were Pgp–, and 124 (64%) were Pgp+. The median follow‐up was 51 months. For Pgp+ patients, 5‐year EFS after definitive surgery (null hypothesis, 40%) was 69.8% (90% confidence interval [CI], 62.2%‐76.2%): 59.8% in PRs and 83.7% in GRs. For Pgp– patients, the 5‐year EFS rate was 66.4% (90% CI, 55.6%‐75.1%).

Conclusions

This study showed that adjuvant mifamurtide, combined with HDIFO for a poor response to induction chemotherapy, could improve EFS in Pgp+ patients. Overall, the outcomes compared favorably with previous series. Mifamurtide and HDIFO as salvage chemotherapy are worth further study.

The expression of ABCB1/P‐glycoprotein (Pgp) at diagnosis has been used to stratify patients with high‐grade osteosarcoma. Adjuvant mifamurtide, combined with high‐dose ifosfamide for a poor response to induction chemotherapy, can improve event‐free survival in Pgp+ patients.

Integrated Molecular Characterization of Patient-Derived Models Reveals Therapeutic Strategies for Treating CIC-DUX4 Sarcoma

Capicua-double homeobox 4 (CIC-DUX4)-rearranged sarcomas (CDS) are extremely rare, highly aggressive primary sarcomas that represent a major therapeutic challenge. Patients are treated according to Ewing sarcoma protocols, but CDS-specific therapies are strongly needed. In this study, RNA sequencing was performed on patient samples to identify a selective signature that differentiates CDS from Ewing sarcoma and other fusion-driven sarcomas. This signature was used to validate the representativeness of newly generated CDS experimental models-patient-derived xenografts (PDX) and PDX-derived cell lines-and to identify specific therapeutic vulnerabilities. Annotation analysis of differentially expressed genes and molecular gene validation highlighted an HMGA2/IGF2BP/IGF2/IGF1R/AKT/mTOR axis that characterizes CDS and renders the tumors particularly sensitive to combined treatments with trabectedin and PI3K/mTOR inhibitors. Trabectedin inhibited IGF2BP/IGF2/IGF1R activity, but dual inhibition of the PI3K and mTOR pathways was required to completely dampen downstream signaling mediators. Proof-of-principle efficacy for the combination of the dual AKT/mTOR inhibitor NVP-BEZ235 (dactolisib) with trabectedin was obtained in vitro and in vivo using CDS PDX-derived cell lines, demonstrating a strong inhibition of local tumor growth and multiorgan metastasis. Overall, the development of representative experimental models (PDXs and PDX-derived cell lines) has helped to identify the unique sensitivity of the CDS to AKT/mTOR inhibitors and trabectedin, revealing a mechanism-based therapeutic strategy to fight this lethal cancer.

SIGNIFICANCE

This study identifies altered HMGA2/IGF2BP/IGF2 signaling in CIC-DUX4 sarcomas and provides proof of principle for combination therapy with trabectedin and AKT/mTOR dual inhibitors to specifically combat the disease.

Primary Malignant Peripheral Nerve Sheath Tumors of Bone: A Clinicopathologic Reappraisal of 8 Cases

Primary spindle cell and pleomorphic sarcomas of bone represent an exceedingly rare group of mesenchymal malignancies that include "soft tissue" histotypes, as malignant peripheral nerve sheath tumour. Outside the head and neck region, only 36 cases of primary malignant peripheral nerve sheath tumour of bone have been described. We retrieved from our archives eight cases of primary malignant peripheral nerve sheath tumour of bone arising outside the head and neck region, describing their clinical, radiological, and morphologic features. Our series, in which all but one patient died of diseases after a median of seven months, confirms that primary malignant peripheral nerve sheath tumours of bone are aggressive tumours. Pathologists should be aware of this rare histotype. More aggressive and active adjuvant treatments should be investigated.

Predictive Value of MRP-1 in Localized High-Risk Soft Tissue Sarcomas: A Translational Research Associated to ISG-STS 1001 Randomized Phase III Trial

MRP-1 is implicated in multidrug resistance and was described as prognostic in high-risk patients with soft-tissue sarcoma (STS) in a previous study. The current research aimed to validate MRP-1 prognostic/predictive value in localized sarcomas treated with anthracyclines plus ifosfamide within the ISG-1001 phase III study. In addition, the inhibitory activity on MRP-1 was investigated in preclinical studies to identify new combinations able to increase the efficacy of standard chemotherapy in STS. MRP-1 expression was assessed by IHC in tissue microarrays from patients with STS and tested for correlation with disease-free survival (DFS) and overall survival (OS). In vitro studies tested the efficacy of MRP-1 inhibitors (nilotinib, ripretinib, selumetinib, and avapritinib) in sarcoma cell lines. The effect of combinations of the most active MRP-1 inhibitors and chemotherapy was measured on the basis of apoptosis. MRP-1 was evaluable in 231 of 264 cases who entered the study. MRP-1 expression (strong intensity) was independently associated with worse DFS [HR, 1.78; 95% confidence interval (CI), 1.11-2.83; P = 0.016], in the multivariate analysis, with a trend for a worse OS (HR, 1.78; 95% CI, 0.97-3.25; P = 0.062). In vitro studies showed that the addition of MRP-1 inhibitors (nilotinib or avapritinib) to doxorubicin plus palifosfamide, significantly increased cell death in SK-UT-1 and CP0024 cell lines. MRP-1 is an adverse predictive factor in localized high-risk patients with STS treated with neoadjuvant anthracyclines plus ifosfamide followed by surgery. In vitro findings support the clinical assessment of the combination of chemotherapy and MRP-1 inhibitors as a promising strategy to overcome the drug ceiling effect for chemotherapy.

Primary synovial sarcoma of bone: A retrospective analysis of 25 patients

AIMS

To evaluate diagnostic accuracy of SSX and SSX-SS18 antibodies in decalcified surgical specimens and outcome of synovial sarcomas (SS) of bone.

METHODS AND RESULTS

Twenty-five cases were classified as bone SS (prevalence 0.32% among malignant primary bone sarcoma). Median age was 34 years (range 9 -79) . 24/25 patients presented with non-metastatic tumors, one with lung metastases. The majority of tumors involved the long bones of extremities with metaphyseal origin. Mean size of the tumor was 7.1 cm. 20 cases (80%) were monophasic and 5 (20%) biphasic. SS18-SSX fusion-specific antibody had 92% sensitivity and 99% specificity for primary bone SS, whereas SSX C-terminus antibody had 100% sensitivity and 94% specificity. FISH analysis was feasible in 9 (36%) cases and detected SS18 rearrangement in all 9 cases. All patients underwent surgical removal of their primary tumor, with adequate margins in 18 (72%) patients. Chemotherapy with metothrexate, cisplatin, doxorubicin, ifosfamide was used in the 7 patients. Two patients with inadequate surgical margins received radiotherapy. With a median follow-up of 80 months (range 6-428), 5-year and 10-year overall survival (OS) were 66.6% and 47.9% respectively and 5-and 10-years disease-free survival (DFS) were 36.8% (95% C.I.: 18.0-55.7%), and 32.2% (95% C.I.: 14.6-51.2%) respectively A significant improvement in 10-years DFS in patients undergoing chemotherapy as compared with patients who did not was observed (p 0.039).

CONCLUSIONS

Our series highlights the utility of SS18-SSX fusion-specific and SSX C-terminus antibodies to support the diagnosis of SS, Adjustment chemotherapy was associated with improved prognosis in this series.

Neoadjuvant chemotherapy in high-risk soft tissue sarcomas: A Sarculator-based risk stratification analysis of the ISG-STS 1001 randomized trial

BACKGROUND

The value of neoadjuvant chemotherapy in soft tissue sarcoma (STS) is not completely understood. This study investigated the benefit of neoadjuvant chemotherapy according to prognostic stratification based on the Sarculator nomogram for STS.

METHODS

This study analyzed data from ISG-STS 1001, a randomized study that tested 3 cycles of neoadjuvant anthracycline plus ifosfamide (AI) or histology-tailored (HT) chemotherapy in adult patients with STS. The 10-year predicted overall survival (pr-OS) was estimated with the Sarculator and was stratified into higher (10-year pr-OS < 60%) and lower risk subgroups (10-year pr-OS ≥ 60%).

RESULTS

The median pr-OS was 0.63 (interquartile range [IQR], 0.51-0.72) for the entire study population, 0.62 (IQR, 0.51-0.70) for the AI arm, and 0.64 (IQR, 0.51-0.73) for the HT arm. Three- and 5-year overall survival (OS) were 0.86 (95% confidence interval [CI], 0.82-0.93) and 0.81 (95% CI, 0.71-0.86) in lower risk patients and 0.69 (95% CI, 0.70-0.85) and 0.59 (95% CI, 0.51-0.72) in the higher risk patients (log-rank test, P = .004). In higher risk patients, the 3- and 5-year Sarculator-predicted and study-observed OS rates were 0.68 and 0.58, respectively, and 0.85 and 0.66, respectively, in the AI arm (P = .04); the corresponding figures in the HT arm were 0.69 and 0.60, respectively, and 0.69 and 0.55, respectively (P > .99). In lower risk patients, the 3- and 5-year Sarculator-predicted and study-observed OS rates were 0.85 and 0.80, respectively, and 0.89 and 0.82, respectively, in the AI arm (P = .507); the corresponding figures in the HT arm were 0.87 and 0.81, respectively, and 0.86 and 0.74, respectively (P = .105).

CONCLUSIONS

High-risk patients treated with AI performed better than predicted, and this adds to the evidence for the efficacy of neoadjuvant AI in STS.

LAY SUMMARY

People affected by soft tissue sarcomas of the extremities and trunk wall are at some risk of developing metastasis after surgery. Preoperative or postoperative chemotherapy has been tested in clinical trials to reduce the chances of distant metastasis. However, study findings have not been conclusive. This study stratified the risk of metastasis for people affected by sarcomas who were included in a clinical trial testing neoadjuvant chemotherapy. Exploiting the prognostic nomogram Sarculator, it found a benefit for chemotherapy when the predicted risk, based on patient and tumor characteristics, was high.

Pexidartinib improves physical functioning and stiffness in patients with tenosynovial giant cell tumor: results from the ENLIVEN randomized clinical trial

Background and purpose - The ENLIVEN trial showed that, after 25 weeks, pexidartinib statistically significantly reduced tumor size more than placebo in patients with symptomatic, advanced tenosynovial giant cell tumor (TGCT) for whom surgery was not recommended. Here, we detail the effect of pexidartinib on patient-reported physical function and stiffness in ENLIVEN.Patients and methods - This was a planned analysis of patient-reported outcome data from ENLIVEN, a double-blinded, randomized phase 3 trial of adults with symptomatic, advanced TGCT treated with pexidartinib or placebo. Physical function was assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS)-physical function (PF), and worst stiffness was assessed using a numerical rating scale (NRS). A mixed model for repeated measures was used to compare changes in PROMIS-PF and worst stiffness NRS scores from baseline to week 25 between treatment groups. Response rates for the PROMIS-PF and worst stiffness NRS at week 25 were calculated based on threshold estimates from reliable change index and anchor-based methods.Results - Between baseline and week 25, greater improvements in physical function and stiffness were experienced by patients receiving pexidartinib than patients receiving placebo (change in PROMIS-PF = 4.1 [95% confidence interval (CI) 1.8-6.3] vs. -0.9 [CI -3.0 to 1.2]; change in worst stiffness NRS = -2.5 [CI -3.0 to -1.9] vs. -0.3 [CI -0.9 to 0.3]). Patients receiving pexidartinib had higher response rates than patients receiving placebo for meaningful improvements in physical function and stiffness. Improvements were sustained after 50 weeks of pexidartinib treatment.Interpretation - Pexidartinib treatment provided sustained, meaningful improvements in physical function and stiffness for patients with symptomatic, advanced TGCT.

Economic burden and health-related quality of life in tenosynovial giant-cell tumour patients in Europe: an observational disease registry

Background

Tenosynovial Giant-Cell Tumour (TGCT) is a benign clonal neoplastic proliferation arising from the synovium, causing a variety of symptoms and often requiring repetitive surgery. This study aims to define the economic burden—from a societal perspective—associated with TGCT patients and their health-related quality of life (HRQOL) in six European countries.

Methods

This article analyses data from a multinational, multicentre, prospective observational registry, the TGCT Observational Platform Project (TOPP), involving hospitals and tertiary sarcoma centres from six European countries (Austria, France, Germany, Italy, the Netherlands, and Spain). It includes information on TGCT patients’ health-related quality of life and healthcare and non-healthcare resources used at baseline (the 12-month period prior to the patients entering the registry) and after 12 months of follow-up.

Results

146 TGCT patients enrolled for the study, of which 137 fulfilled the inclusion criteria. Their mean age was 44.5 years, and 62% were female. The annual average total costs associated with TGCT were €4866 at baseline and €5160 at the 12-month follow-up visit. The annual average healthcare costs associated with TGCT were €4620 at baseline, of which 67% and 18% corresponded to surgery and medical visits, respectively. At the 12-month follow-up, the mean healthcare costs amounted to €5094, with surgery representing 70% of total costs. Loss of productivity represented, on average, 5% of the total cost at baseline and 1.3% at follow-up. The most-affected HRQOL dimensions, measured with the EQ-5D-5L instrument, were pain or discomfort, mobility, and the performance of usual activities, both at baseline and at the follow-up visit. Regarding HRQOL, patients declared a mean index score of 0.75 at baseline and 0.76 at the 12-month follow-up.

Conclusion

The results suggest that TGCT places a heavy burden on its sufferers, which increases after one year of follow-up, mainly due to the healthcare resources required—in particular, surgical procedures. As a result, this condition has a high economic impact on healthcare budgets, while the HRQOL of TGCT patients substantially deteriorates over time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-01883-5.

Epithelioid hemangioendothelioma, an ultra-rare cancer: a consensus paper from the community of experts

Epithelioid hemangioendothelioma (EHE) is an ultra-rare, translocated, vascular sarcoma. EHE clinical behavior is variable, ranging from that of a low-grade malignancy to that of a high-grade sarcoma and it is marked by a high propensity for systemic involvement. No active systemic agents are currently approved specifically for EHE, which is typically refractory to the antitumor drugs used in sarcomas. The degree of uncertainty in selecting the most appropriate therapy for EHE patients and the lack of guidelines on the clinical management of the disease make the adoption of new treatments inconsistent across the world, resulting in suboptimal outcomes for many EHE patients. To address the shortcoming, a global consensus meeting was organized in December 2020 under the umbrella of the European Society for Medical Oncology (ESMO) involving >80 experts from several disciplines from Europe, North America and Asia, together with a patient representative from the EHE Group, a global, disease-specific patient advocacy group, and Sarcoma Patient EuroNet (SPAEN). The meeting was aimed at defining, by consensus, evidence-based best practices for the optimal approach to primary and metastatic EHE. The consensus achieved during that meeting is the subject of the present publication.

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This consensus paper provides key recommendations on the management of epithelioid hemangioendothelioma (EHE).

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Recommendations followed a consensus meeting between experts and a representative of the EHE advocacy group and SPAEN.

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Authorship includes a multidisciplinary group of experts from different institutions from Europe, North America and Asia.

Efficacy of dose intensification in induction therapy for localized Ewing sarcoma: Italian Sarcoma Group (ISG) and Associazione Italiana Ematologia ed Oncologia Pediatrica (AIEOP) ISG/AIEOP EW-1 study

11501

Background: The role of dose intensification of chemotherapy in Ewing sarcoma (ES) is under evaluation in prospective trials. This is a controlled, randomized phase III study evaluating the impact on event-free survival (EFS) of two arms at different intensity of induction therapy in localized ES at onset. Methods: Newly diagnosed localized ES patients aged 2-40 were eligible. They were randomized to receive 4-courses induction therapy - 1 every 21 days - either with a standard arm (arm A) as per ISG/SSGIII protocol (Ferrari S, et at, Ann Oncol. 2011;22(5):1221) or with an intense arm B, consisting of vincristine 1,5mg/sqm+ doxorubicin 80mg/sqm+ifosfamide 9g/sqm for each course. After induction, patients underwent surgery and/or radiotherapy,followed by an adaptive treatment. Good responders received standard courses chemotherapy: arm A pts received 9 courses, while arm B pts received 5 courses. Poor responders in both arms received 4 courses followed by high-dose busulfan/melphalan+autologous stem cell rescue. The primary outcome measure was EFS for the 2 arms in the intention-to-treat population. Kaplan-Meier curves compared with log-rank test and Cox model were performed to assess differences between study arms. A secondary outcome was toxicity differences, assessed by means of the Fisher’s exact test. Initial sample size was 230 pts, type I error rate 5%, power 80%. Results: Between 2009 and 2019, 234 patients were randomized (arm A-115; arm B-119). M:F ratio was 1.8; median age 14 years (range 2-40); tumour site extremity in 55%, axial/pelvis in 45%; tumour volume < 200ml in 31% and ≥200ml in 69%. A good response was obtained in 56% in arm A and 60% in arm B. Median follow-up was 68 months. EFS was not significantly different between arms; HR: 0.85; 95% CI: 0,51-1,41, 5-year EFS (95% CI) was 73% (64-82%) in arm A and 75% (67-83%) in arm B ( p = 0.526). Good responders in arm A and in arm B and poor responders in arm B had comparable results: 5-year EFS (95% CI) was 80% (71-91%), 77% (67-88%), and 72% (59-86%), respectively, while poor responders in arm A showed a worse, not statistically significant (p = 0.164) performance (63%; 50-78%). Subgroup analyses showed similar outcome for age, tumour site and volume in both arms. Hematological, gastrointestinal, and cardiovascular grade ≥3 toxicities were more pronounced in arm B (p < 0.05). Conclusions: Intense induction therapy with arm B did not improve 5-year EFS when compared with the standard arm A. The higher toxicity observed in arm B than in arm A was counterbalanced, in good responders, by a similar outcome with a shorter treatment plan. For poor responders, with almost 30 patients per arm event-free and with < 48-month FUP, better 5-year EFS in arm B than in arm A was observed but needs further observation. Clinical trial information: NCT02063022.

Localized osteosarcoma analysis of very poor responders subgroup (Huvos I)

e22010

Background: Osteosarcoma is a malignant primitive bone tumor whose prognosis is not changed since 4 decades, after the introduction of neoadjuvant chemotherapy with Methotrexate, Cisplatin, Doxorubicine and Ifosfamide. Histologic response to preoperative chemotherapy is a significant prognostic factor. Huvos I (necrosis ≤ 50%) has worst prognosis . Previous studies reported a 3 years EFS of this Huvos I patients around 25% (Tsuda Y,2020). In order to evaluate if survival has changed in recent years in this unfavourable prognostic group we evaluated the outcome of osteosarcoma patients with Huvos I. Methods: from our Pathology archieves we retrieved all cases of localized osteosarcoma treated at Rizzoli with neoadjuvant chemotherapy who reported an histologic necrosis below or equal to 50% (Huvos I grade) after preoperative chemotherapy MAP (Ethical C. Approval 917/2020/Oss/IOR). Results: from 2003 to 2019 we had 70 cases of localized osteosarcoma with Huvos I necrosis after neoadjuvant chemotherapy ( MAP in 66 and MAPI in 4) evaluable. Median age 21,5 (3-70); M:F = 44:26. 10/70 had axial localization vs extremity(60), subhistotype distribution:46 osteoblastic,11 chondroblastic, 7 fibroblastic, 5 teleangectatic, one not classified. In 24 cases PgP was available(14 PgP positive). With a median follow up of 86.7 ms (IQR 41-136) 43/70 had already relapsed. The median EFS was 25 ms (95% CI 15-42) and the 3 yrs EFS was 40.6% (95% CI 29-52). The 3 yrs overall survival was 80% (95%CI 68-88) and median OS was not reached. Axial tumor site was associated with significant inferior EFS (P = .004). Conclusions: these data confirm the poor prognosis of patients with necrosis ≤50% and the need of new drugs to improve their survival in this sub-group.

Immune contexture in high-risk soft tissue sarcomas (STS): A planned analysis of the ISG-STS-1001 randomized trial

11572

Background: The characteristics of immune contexture and its prognostic and predictive value in STS is left to be understood. This planned analysis of the ISG-STS-1001 trial, which compared neoadjuvant anthracycline + ifosfamide (AI) vs a histology-tailored (HT) chemotherapy (ChT), was aimed at characterizing the immune contexture after neoadjuvant ChT and investigating any association with the risk of recurrence. Methods: Patients registered in the ISG-STS-1001 study (ID: NCT01710176) were included if they had tumor tissue available for Tissue MicroArray (TMA), which was performed in the area of the surgical specimen with the highest lymphocyte infiltrate. The following markers were analyzed with IHC and measured quantitatively: CD3, CD8, PD1, GranzymeB, Foxp3, CD20, CD163, and PDL1. The T-Distributed Stochastic Neighboring Entities (t-SNE) analysis was used to account for the co-expression of IHC markers in each tumor. The prognostic value of each marker for disease-free survival (DFS) was assessed. Results: This analysis was conducted in 256 of 435 study patients. AI and HT neoadjuvant ChT did not result in any different distribution of immune contexture. Conversely, differences were observed between ‘complex’ karyotype STS (ck-STS: LMS, MPNST, UPS, MFS, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma) and ‘simple’ karyotype STS (sk-STS: MLPS and SS). Ck-STS were enriched in both CD3+ and CD8+ cells compared to sk-STS. These cells displayed an heterogeneous distribution and were dispersed inside the tumor nest, keeping direct contact with sarcoma cells. Ck-STS also displayed an enrichment in Granzyme B+, and CD163+ cells. PDL1+ cells were occasionally identified and were more frequent in ck-STS, suggesting an immune-related expression. Most STS were negative for CD20+ cells, however, when present these cells were highly represented and organized in tertiary lymphoid-like structure. The t-SNE generated plot clustered tumors, the ‘cold’ mainly including sk-STS and the ‘hot’ mainly composed by ck-STS. In the ‘hot’ group, a cluster of tumors displayed an immune infiltrate enriched with a high number of CD3, CD8, GranzymeB, PD-1, and PDL-1+ cells. When the prognostic value of the immune markers was investigated, the presence of CD20+ cells was the only independent prognostic factor for DFS (HR=0.68, 95%CI 0.52-0.91) in a histology-stratified estimate adjusting for tumor size in cm (HR=1.07, 95%CI 1.03-1.12) and patient age (HR=1.0, 95%CI 0.97-1.02). Conclusions: Immune contexture differed across sarcoma histologies after neoadjuvant ChT, rather than across the two study arms, with ck-STS being marked by a rich immune contexture. While a CD20+ infiltrate was found to be an independent prognostic factor for a better outcome, further analyses are in progress on the prognosis of patients with the richest immune contexture. Clinical trial information: NCT01710176.

Metastatic osteosarcoma at diagnosis: Analysis of 92 cases from a single institution

e23506

Background: Metastatic osteosarcoma (MOS) with synchronous metastases accounts for 20-25% of all new cases of osteosarcoma. Lungs are the most common site of metastases at presentation (80%) followed by Bone (10%). 5- years Overall Survival (OS) of MOS ranges from 11 to 40%. In a previous study from our institution (Bacci G 2006) on 57 pts < 40 years old (1995-2000) the 2- and 5-year OS were 55% and 18%. Methods: Data of patients with pathologic and radiologic confirmed MOS with adequate follow up were reviewed (EC Approval N 916/2020/Oss/IOR). Time-to-event outcomes were estimate with Kaplan-Meier method and compared between groups with log-rank test and Cox model. Results: From August 2000 to October 2018, 92 patients had a diagnosis of MOS: median age 16.5 yrs (6-73, twelve pts > 40 ), gender rate was M 51/F 41, axial primary tumor in 15 cases, extremity in 77. Lung only metastases were described in 66 (71.7%). In 75/90 cases primary tumor was surgically removed, 43 (46%) cases had at least one surgical metastasectomy. All patients received chemotherapy: preoperative only in 6 cases, postoperative in 6, and pre and postoperative in 66 patients. The 1st line chemotherapy was a combination of drugs: Adriamycin in 91/92 pts, Cisplatin in 89/92, Ifosfamide in 88/92, Methotrexate in 83/92; 59 patients received a 2nd line chemotherapy, 34 pts received a 3rd line; most employed regimen were Gemcitabine-Docetaxel, Ifosfamide 15 gr/m2, Cyclophosphamyde-Etoposide, TKI (Pazopanib, Sorafenib), and a few received experimental drugs. Complete remission (CR) was obtained in 26/92 (28%), in 19 cases after surgical metastasectomy.In 30 pts the information of PGP (P- glycoprotein) was available; patients with positive PGP (19/30) had a worst overall survival as compared to those PGP negative (P = 0.038). Of those in Complete Remission 14/26 relapsed. At December 2020 with a median follow-up of 95 ms (IQR 34-159): 65/92 (70%) died , 12 are alive and free from disease , 6 are alive with disease, 9 were lost . The 2-yrs OS for all 92 pts from diagnosis was 66% (95%CI 55-75) and 5-yrs OS was 26% (95% CI 16-37). From the end of treatment, for those who reached a CR the 5-year OS was 57% vs 9% for those who did not (P < 0.001). At univariate analysis, primary tumor site (2-y OS 48% axial vs 72% extremity, P < 0.001), site of metastases (2-y OS 74% only lung vs 48% other, P = 0.004) and number of lung nodules (P = 0.007), were significantly associated to OS. At multivariate analysis, only site of metastases (other vs. only lung HR = 2.26, 95%CI: 1.21-4.22) and number of lung nodules (≥10 nodules vs ≤3 HR = 2.44, 95%CI: 1.24-4.81) were confirmed as significant for OS. Conclusions: Compared to our previous report from 20 yrs ago, 2-years and 5 yrs OS of MOS has improved but it remain unsatisfactory (66% vs 55% and 26% vs 18%).

Inflammatory indexes neutrophils/lymphocytes, platelets/lymphocytes and red-cell distribution width (RDW) as prognostic biomarkers in advanced solitary fibrous tumors (SFT) treated with pazopanib: Correlative study of GEIS-32 trial

11511

Background: Pazopanib (P) was assessed prospectively in a phase 2 study in SFT resulting in a longer progression free survival (PFS) and overall survival (OS) compared to historical controls treated with chemotherapy. No statistical correlation was found between angiogenic factors and P in its pivotal phase III sarcoma trial. In the last two years, a soaring interest on the prognostic and predictive value of inflammatory indexes such as neutrophil/lymphocyte (NLR) and platelet/lymphocyte (PLR) is emerging in sarcomas. A retrospective analysis of inflammatory indexes of patients who entered the GEIS-32 (NCT02066285) trial was performed. In that trial advanced SFT patients were treated with P from front-line. Methods: All eligible patients who entered in the typical- and malignant-SFT cohort of the GEIS-32 trial were included in this analysis. To determine NLR and PLR, baseline values of platelets (10e9/L), neutrophils (10e9/L) and lymphocytes (10e9/L) were obtained from complete blood count tests. Additionally, RDW (standardized as 1 = upper value of normal range) values at baseline were also determined. The impact of NLR, PLR and RDW on OS, PFS and Choi response were analyzed by univariate and multivariate analysis. MAXSTAT was used to determine optimal cut-off points for overall survival. Metastasis free interval (MFI), mitotic count and ECOG were also analyzed, among others. Results: Sixty-seven out of 70 enrolled SFT patients, median age 63-y and 57% female, were considered for this analysis. The median follow-up from treatment initiation was 20.0 months. High standardized RDW value at baseline (cut-off 1.03) was significantly associated with worse OS [10.7 months (95% CI 3.8-17.5) vs 49.8 months (95% CI 9.4-90.2), p < 0.001] and worse PFS [8.8 months (95% CI 0.9-7.0) vs 9.8 months (7.4-12.3), p = 0.001]. High PLR (cut-off 242) significantly correlated with worse OS [10.7 months (95% CI 5.2-16.2) vs 49.8 months (95% CI 14.6-85.0), p < 0.001] and worse PFS [4.5 months (95% CI 2.0-7.0) vs 10.1 months (95% CI 6.3-13.9), p = 0.005], and high NLR (cut-off 3.78) was significantly associated with worse OS [11.7 months (95% CI 3.5-19.8) vs NA, p < 0.001] and worse PFS [4.5 months (95% CI 1.9-7.0) vs 10.8 months (95% CI 8.7-12.9), p = 0.010]. Independent variables in multivariate analysis were NLR, RDW, MFI and mitosis for PFS; while RDW and ECOG for OS (see table). Further, NLR and mitosis were independent factors for Choi progressive disease (as best response). Conclusions: High NLR and RDW values were independent biomarkers of worse outcome in advanced SFT patients treated with pazopanib.[Table: see text]