The observational EURACAN prospective clinical registry dedicated to epithelioid hemangioendothelioma: The protocol of an international and collaborative effort on an ultra-rare entity.

INTRODUCTION: Epithelioid hemangioendothelioma (EHE) is an ultra-rare sarcoma, marked by distinctive molecular and pathological features and with a variable clinical behavior. Its natural history is still partially understood, reliable prognostic and predictive factors are lacking and many questions are still open on the optimal management. In the context of EURACAN, a prospective registry specifically dedicated to EHE was developed and launched with the aim of providing, through high-quality prospective data collection, a better understanding of this disease. STUDY DESIGN: Registry-based cohort study including only new cases of patients with a pathological and molecularly confirmed diagnosis of EHE. OBJECTIVES: To improve the understanding of EHE natural history, validate and identify new prognostic and predictive factors, clarify the activity and efficacy of currently available treatment options, describe treatment pattern. METHODS: Settings and participantsIt is an hospital-based registry established in centers with expertise in EHE including adult patients with a new pathological and molecularly confirmed diagnosis of EHE starting from the 1st December 2023. The characteristics of each patient in the facility who meets the above-mentioned inclusion criteria will be collected prospectively and longitudinally with follow-up at cancer progression and / or cancer relapse or patient death. It is a secondary use of data which will be collected from the clinical records. The data collected for the registry will not entail further examinations or admissions to the facility and/or additional appointments to those normally provided for routine patient follow-up. VariablesFull details on patients and disease features, treatment and outcome will be collected, according to common clinical practice guidelines developed and shared with all the contributing centers. In addition, data on potential confounders (e.g. comorbidity; functional status etc.) will also be collected. Statistical methodsThe data analyses will include descriptive statistics and analytical analyses. Multivariable Cox's proportional hazards model and Hazard ratios (HR) for all-cause or cause-specific mortality will be used to determine independent predictors of overall survival, recurrence and progression. RESULTS: The registry has been joined by 21 sarcoma reference centers across EU and UK, covering 10 countries. Patients' recruitment started in December 2023. The estimated completion date is December 2033 upon agreement on the achievement of all the registry objectives. The already established collaboration and participation of EHE patient's associations involved in the project will help in promoting the registry and fostering accrual.

Hemodialysis and imatinib: Plasma levels, efficacy and tolerability in a patient with metastatic GIST - Case report.

Purpose: To study plasma levels, efficacy and tolerability of imatinib in a patient affected by metastatic GIST treated with oral Imatinib and undergoing hemodialysis. Patients and methods: The patient suffered from metastatic GIST to the liver having a mutation of exon 9 of KIT. He was on hemodialysis and received first-line treatment with imatinib 400 mg/day. Results: The overall mean plasma level of imatinib was 1875,4 ng/ml pre-dialysis, 1553,0 ng/ml post-dialysis and 1998,1 ng/ml post-24h. In red blood cells the overall mean level of imatinib was 619,5 ng/ml pre-dialysis, 484,9 ng/ml post-dialysis and 663,1 ng/ml post-24h. The plasma level of nor-imatinib/imatinib was 16,2% pre-dialysis, 15,6% post-dialysis and 16,4% post-24h. Comparing our findings regarding levels of imatinib in plasma and RBC, we found a statistically significant difference between pre-dialysis and post-dialysis (respectively p < 0,001 and p = 0,002), post-dialysis and post-24h (both p < 0,001), pre-dialysis and post-24h (respectively p = 0.035 and p = 0,042). Ultimately, regarding nor-imatinib/imatinib in plasma, we did not find any statistically significant difference between pre-dialysis and post-dialysis (p = 0,091), post-dialysis and post-24h (p = 0,091), pre-dialysis and post-24h (p = 0.903). Currently the patient is receiving oral imatinib 400 mg/day with radiological evidence of response. Conclusion: In this case, hemodialysis did not affect significantly imatinib plasma levels. The statistically significant difference between pre- and post-dialysis can be explained by the fact that dialysis may likely contribute to a small portion of the normal metabolism of imatinib. The evaluation of imatinib levels in RBC and of its main metabolite in plasma also suggests that hemodialysis did not affect other aspects of the elimination of the drug.

Long-term survivors with desmoplastic small round cell tumor (DSRCT): Results from a retrospective single-institution case series analysis.

OBJECTIVE: To report on a retrospective study of primary DSRCT aiming at characterizing long-term survivors (LTS). METHODS: All consecutive patients treated at our institution for a primary DSRCT between 2000 and 2021 were retrospectively identified. Patients received multiagent chemotherapy ± surgery ± hyperthermic intraperitoneal chemotherapy (HIPEC) ± whole abdomino-pelvic radiotherapy (WAP-RT) ± high-dose chemotherapy ± maintenance chemotherapy (MC). Event-free survival (EFS) and overall survival (OS) were estimated by Kaplan-Meier method. Patients alive, without evidence of disease at ≥36 months from diagnosis, were defined as LTS. RESULTS: Thirty-eight patients were identified. All received multiagent chemotherapy; 27/38 (71%) surgery (7/27 [26%] plus HIPEC), 9/38 (24%) WAP-RT, 12/38 (32%) MC. At a median-follow-up of 37 months (IQR 18-63), overall median-EFS and median-OS were 15 and 37 months, respectively. All events occurred within 35 months. In patients who underwent surgery, median-EFS and median-OS were 19 and 37 months (23 and 43 months after R0/R1, and 10 and 19 months after R2 resection), respectively. LTS were 5/38 (13%), alive at 37, 39, 53, 64, 209 months. None had liver or extra-abdominal metastasis at diagnosis, they all received R0/R1 resection, 3/5 had WAP-RT, 2/5 MC, 1/5 received high-dose chemotherapy, none HIPEC. CONCLUSIONS: In our series cure was likely achieved in 13% of DSRCT. LTS had no liver/extra-abdominal disease, were treated with complete surgery, and possibly WAP-RT/MC.

Effectiveness and Safety of Trabectedin and Radiotherapy for Patients With Myxoid Liposarcoma: A Nonrandomized Clinical Trial.

Importance: Preclinical data about the synergistic activity of radiotherapy (RT) and trabectedin have been reported. The combination of trabectedin and RT in treating myxoid liposarcomas appears worth exploring. Objective: To explore the effectiveness and safety of trabectedin combined with RT. Design, Setting, and Participants: This international, open-label, phase 2 nonrandomized clinical trial including 46 patients with myxoid liposarcoma was conducted in 4 centers in Spain, 1 in Italy, and 2 in France from July 1, 2016, to September 30, 2019. Eligible patients had to have a histologic, centrally reviewed diagnosis of localized resectable myxoid liposarcoma arising from an extremity or the trunk wall. Interventions: Trabectedin was administered at the recommended dose stemming from the phase 1 trial (1.5 mg/m2), with intravenous infusion during 24 hours every 21 days for a total of 3 cycles. Radiotherapy was started after completion of the first trabectedin infusion (cycle 1, day 2). Patients received 25 fractions of radiation for a total of 45 Gy. Surgery was planned 3 to 4 weeks after the administration of the last preoperative cycle and not until 4 weeks after the end of preoperative RT. Pathologic specimens were mapped in tumor sections to estimate the histologic changes and the percentage of viable tumor after neoadjuvant treatment. Main Outcomes and Measures: The primary objective of the phase 2 part of the study was overall response. Secondary objectives were effectiveness measured by relapse-free survival and activity measured by functional imaging and pathologic response. Results: A total of 46 patients were enrolled. Four patients were not evaluable. The median age was 43 years (range, 18-77 years), and 31 patients were male (67%). Overall, 9 of 41 patients (22%) achieved a partial response with neoadjuvant treatment with trabectedin and RT, with 5 of 39 patients (13%) achieving a complete pathologic response and 20 of 39 patients (51%) having 10% or less of a viable remaining tumor. Partial responses according to Choi criteria were observed in 24 of 29 evaluable patients (83%), and no patient had disease progression. Treatment was well tolerated. Conclusions and Relevance: Although the primary end point of this phase 2 nonrandomized clinical trial was not met (Response Evaluation Criteria in Solid Tumors response in ≥70% of patients), results suggest this combination was well tolerated and effective in terms of pathologic response. Thus, trabectedin plus RT might be a treatment option regarding tolerability; further evidence should be generated in this setting.

Trabectedin use in soft-tissue sarcoma patients in a real-world setting: Data from an Italian national drug-access registry.

Trabectedin is a marine-derived anticancer drug approved for the treatment of patients with advanced soft-tissue sarcomas (STS). Here, we aimed to analyze its use in a large cohort of STS patients treated in Italy in a real-world setting. Data on STS patients treated with trabectedin in Italy were prospectively collected from January 2013 to December 2019 by the national drug regulator, the Italian Medicines Agency (AIFA). Time-to-off-treatment (TToT) was defined as the time between the initial prescription of trabectedin and the date of treatment discontinuation for any cause. The impact of the different baseline covariates, including the initial prescribed dose of trabectedin, on TToT was evaluated using an accelerated failure time (AFT) models with log-logistic distribution. In total, we analyzed data from 2633 sarcoma patients and 14 950 individual cycles of trabectedin. The median number of cycles of trabectedin received per patient was 3 (interquartile range 2-7). The labeled 1.5 mg/sqm dose was used in 27.3% of all first prescriptions. Overall, the median TToT was 93 days. In the final AFT model, the variables significantly associated to longer TToT were female gender (+13% increase in TToT); ECOG performance status 0 (+50%); histological diagnosis of leiomyosarcoma (+22%), well-differentiated/dedifferentiated liposarcoma (+72%) or myxoid liposarcoma (+61%); receiving treatment in a high-volume center (+23%). In this large real-world cohort of STS patients treated with trabectedin, our findings support the use of trabectedin in STS patients, in particular in leiomyosarcoma and liposarcoma patients, and highlight the role of treatment center volume in their management.

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.

Is rare cancer care organized at national health system level? Multiple case study in six EU countries.

BACKGROUND: As a system of European Reference Networks (ERNs) emerges, the differences in quality of care for patients with rare cancers may increase at national level. We aimed to elucidate the processes and healthcare planning principles through which the reference centres (RCs) for rare cancers are embedded in national health systems. METHODS: We used a multiple case-study design based on the experiences of Czechia, Finland, France, Italy, Lithuania and Spain. Using sarcoma as an example of rare cancer, 52 semi-structured interviews were conducted during on-site visits, including a multidisciplinary group of professionals, Ministry of Health professionals, patient representatives and European policymakers. RESULTS: The comparative analysis showed substantial heterogeneity in the processes for formalizing RCs' status and in their levels of integration in the different health systems, but two models (centre-based and the network-based) can be envisaged at national level. RCs for rare cancers were legally established only in France and Spain. Expert clinicians cooperate in a structured way, using network mechanisms, in France and Italy, and these countries, plus Finland and Lithuania, had a referral system to facilitate patients' access from non-expert centres to RCs. Seven key healthcare planning principles in instituting RCs at the national level were identified. CONCLUSIONS: The conditions governing patient access to treatment centres-whether RCs or not-are decided at the national level. It is advisable to progressively align the European and national levels so that the RCs that participate in the ERNs also play a significant role at the national level.

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.

[The problem of rare cancers.] / Il problema dei tumori rari.

Rare cancers are malignant tumors with an incidence lower than 6/100,000/year at the EU level. Even if more conservative in comparison to the definition used for rare diseases (also from the regulatory point of view), rare cancers defined this way make up more than twenty percent of new cases of malignant tumors in the EU, including Italy. The rarity of a tumor implies that clinical decision-making is more problematic outside reference centers and networks, that available evidence suffers from a higher uncertainty, that organization of health care is more difficult. In 2019, a Joint Action on rare cancers launched by the European Union, run in parallel to a Joint Action on rare diseases, worked out ten categories of recommendations, among which some on the methodology of clinical research and regulatory aspects. In general, it stressed the value of collaborative clinical networks (at the EU level and, more importantly, nationally) around centers of expertise. Working according to a "hub-and-spoke" logic, these networks can improve quality of care while rationalizing health migration. Regarding the regulatory aspects and more in general to the definition of the state of art, in rare cancers the magnitude of clinical benefit should be the same as for common conditions, but the quality of evidence should be accepted to be less stringent in terms of statistical precision. Otherwise, rare cancer patients would be discriminated against in their access to innovative diagnostic and therapeutic options, even when available. Specifically, orphan drugs can suffer from lower interest of pharmaceutical industry. This justifies some privileges they are granted, among which the 10-year market exclusivity is crucial. However, a critical aspect is the perception of the regulatory risk by the industry. This problem could be limited by closer cooperation between regulatory bodies and rare cancer communities and by flexible regulatory mechanisms, in particular in partnership with clinical networks. In Italy, more constructive interpretations of the rules about the compassionate use of drugs, an even application of Law 648 and the future implementation of the new Law on Rare Diseases could help. In general, refining the methodology of clinical research in small samples would be fundamental.

Ethical issues in oncology practice: a qualitative study of stakeholders' experiences and expectations.

BACKGROUND: Clinical Ethics Support Services (CESS) have been established to support healthcare professionals in addressing ethically sensitive issues in clinical practice and, in many countries, they are under development. In the context of growing CESS, exploring how healthcare professionals experience and address clinical ethics issues in their daily practice represents a fundamental step to understand their potential needs. This is even more relevant in the context of extremely sensitive diseases, such as cancer. On this basis, we carried out a qualitative study conducting in-depth semi-structured interviews with stakeholders of a major comprehensive cancer centre in Italy, with the twofold aim of investigating what ethical issues arise in the context of clinical oncology and how they are addressed, as well as stakeholders' expectations about a potential CESS to be implemented within the Institution. METHODS: The study was conducted within the theoretical framework of Grounded Theory. Participants were healthcare professionals and other key stakeholders working within the cancer centre. The semi-structured interview aimed at exploring common ethical aspects of oncology, investigating stakeholders' professional experience in dealing with clinical ethics issues, their expectations and requests regarding ethics support services. Transcripts of the interviews were coded and analysed according to the principles of Grounded Theory. RESULTS: Twenty-one stakeholders were interviewed. Our analysis showed a wide consensus on the identification of ethically relevant issues, above all those concerning communication, end-of-life, and resource allocation. The absence of institutional tools or strategies to address and manage ethical issues at the patient bedside emerged, and this is reflected in the widespread request for their development in the future. The ideal support service should be fast and flexible in order to adapt to different needs and clinical cases. CONCLUSIONS: The interviewees showed a limited degree of 'ethical awareness': despite having reported many issues in clinical practice, they could hardly identify and describe the ethical aspects, while  complaining about a lack of ethical resources in their management. To build a truly effective support service, it therefore seems appropriate to take such context into consideration and address the emerged needs. Ethical sensitivity seems to be key and it becomes even more relevant in critical clinical areas, such as the therapeutic pathways of terminally ill patients.

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.

Weekly cisplatin with or without imatinib in advanced chordoma: A retrospective case-series analysis from the Italian Rare Cancers Network.

BACKGROUND: To report on a retrospective case-series analysis of weekly cisplatin (wCDDP) as a single agent or combined with imatinib (wCDDP/I) in patients with advanced chordoma treated within the Italian Rare Cancer Network. METHODS: Adult patients with a diagnosis of advanced, brachyury-positive chordoma, treated from April 2007 to October 2020 with wCDDP or wCDDP/I were retrospectively identified. Imatinib was withheld at the same time as wCDDP. Response according to Response Evaluation Criteria in Solid Tumors, overall survival (OS), and progression-free survival (PFS) were analyzed. RESULTS: Thirty-three consecutive patients were identified (wCDDP as front-line n = 8 [24.2%]; wCDDP as a further line n = 25 [75.8%]; prior imatinib n = 25 [75.8%]; evidence of progression before starting wCDDP n = 33). Of 32 patients evaluable for response (wCDDP, n = 22 [68.8%]; wCDDP/I, n = 10 [31.3%]), best response was stable disease (SD) in 27 patients (84.3%) and progression in 5 patients (15.6%). At a median follow-up of 54 months, the median OS (m-OS) was 30.3 months (interquartile range [IQR], 18.1-56.6), the m-PFS was 8.0 months (IQR, 5.1-17.0), the 6-month PFS rate was 65.2%, and the 12-month PFS rate was 30.3%. Of 22 patients who received wCDDP, the best response was SD in 18 patients (81.8%) and progression in 4 patients (18.2%), and the m-PFS was 8.0 months (IQR, 5.1-17.0 months). Of 10 patients who received treatment with wCDDP/I, the best response was SD in 9 patients (90%) and progression in 1 patient (10%), and the m-PFS was 9.3 months (IQR, 4.9-26.5 months). CONCLUSIONS: This series suggests that wCDDP, both as a single agent and combined with imatinib, has antitumor activity in chordoma. Although no dimensional responses were observed, 65% and 30% of previously progressive patients were progression-free at 6 and 12 months, respectively. A prospective study is warranted.

Adjuvant Imatinib in Patients with GIST Harboring Exon 9 KIT Mutations: Results from a Multi-institutional European Retrospective Study.

PURPOSE: The effect of high-dose imatinib (800 mg/day) on survival in the adjuvant treatment of patients with resected KIT exon 9-mutated gastrointestinal stromal tumors (GIST) is not established. Here, the association of dose and other clinicopathologic variables with survival was evaluated in a large multi-institutional European cohort. EXPERIMENTAL DESIGN: Data from 185 patients were retrospectively collected in 23 European GIST reference centers. Propensity score matching (PSM) and inverse-probability of treatment weighting (IPTW) were used to account for confounders. Univariate and multivariate unweighted and weighted Cox proportional hazard regression models were estimated for relapse-free survival (RFS), modified-RFS (mRFS) and imatinib failure-free survival (IFFS). Univariate Cox models were estimated for overall survival. RESULTS: Of the 185 patients, 131 (70.8%) received a starting dose of 400 mg/d and the remaining 54 (29.2%) a dose of 800 mg/d. Baseline characteristics were partially unbalanced, suggesting a potential selection bias. PSM and IPTW analyses showed no advantage of imatinib 800 mg/d. In the weighted multivariate Cox models, high-dose imatinib was not associated with the survival outcomes [RFS: hazard ratio (HR), 1.24; 95% confidence interval (CI), 0.79-1.94; mRFS: HR, 1.69; 95% CI, 0.92-3.10; IFFS: HR, 1.35; 95% CI, 0.79-2.28]. The variables consistently associated with worse survival outcomes were high mitotic index and nongastric tumor location. CONCLUSIONS: In this retrospective series of patients with KIT exon 9-mutated GIST treated with adjuvant imatinib, a daily dose of 800 mg versus 400 mg did not show better results in terms of survival outcomes. Prospective evaluation of the more appropriate adjuvant treatment in this setting is warranted.

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.

Mechanisms of responsiveness to and resistance against trabectedin in murine models of human myxoid liposarcoma.

Myxoid liposarcoma (MLPS) is a rare soft-tissue sarcoma characterised by the expression of FUS-DDIT3 chimera. Trabectedin has shown significant clinical anti-tumour activity against MLPS. To characterise the molecular mechanism of trabectedin sensitivity and of resistance against it, we integrated genomic and transcriptomic data from treated mice bearing ML017 or ML017/ET, two patient-derived MLPS xenograft models, sensitive to and resistant against trabectedin, respectively. Longitudinal RNA-Seq analysis of ML017 showed that trabectedin acts mainly as a transcriptional regulator: 15 days after the third dose trabectedin modulates the transcription of 4883 genes involved in processes that sustain adipocyte differentiation. No such differences were observed in ML017/ET. Genomic analysis showed that prolonged treatment causes losses in 4p15.2, 4p16.3 and 17q21.3 cytobands leading to acquired-resistance against the drug. The results dissect the complex mechanism of action of trabectedin and provide the basis for novel combinatorial approaches for the treatment of MLPS that could overcome drug-resistance.

Ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society community of experts on the incidence threshold and the list of entities.

BACKGROUND: Among sarcomas, which are rare cancers, many types are exceedingly rare; however, a definition of ultra-rare cancers has not been established. The problem of ultra-rare sarcomas is particularly relevant because they represent unique diseases, and their rarity poses major challenges for diagnosis, understanding disease biology, generating clinical evidence to support new drug development, and achieving formal authorization for novel therapies. METHODS: The Connective Tissue Oncology Society promoted a consensus effort in November 2019 to establish how to define ultra-rare sarcomas through expert consensus and epidemiologic data and to work out a comprehensive list of these diseases. The list of ultra-rare sarcomas was based on the 2020 World Health Organization classification, The incidence rates were estimated using the Information Network on Rare Cancers (RARECARENet) database and NETSARC (the French Sarcoma Network's clinical-pathologic registry). Incidence rates were further validated in collaboration with the Asian cancer registries of Japan, Korea, and Taiwan. RESULTS: It was agreed that the best criterion for a definition of ultra-rare sarcomas would be incidence. Ultra-rare sarcomas were defined as those with an incidence of approximately ≤1 per 1,000,000, to include those entities whose rarity renders them extremely difficult to conduct well powered, prospective clinical studies. On the basis of this threshold, a list of ultra-rare sarcomas was defined, which comprised 56 soft tissue sarcoma types and 21 bone sarcoma types. CONCLUSIONS: Altogether, the incidence of ultra-rare sarcomas accounts for roughly 20% of all soft tissue and bone sarcomas. This confirms that the challenges inherent in ultra-rare sarcomas affect large numbers of patients.

Systemic therapies in advanced epithelioid haemangioendothelioma: A retrospective international case series from the World Sarcoma Network and a review of literature.

BACKGROUND: This observational, retrospective effort across Europe, US, Australia, and Asia aimed to assess the activity of systemic therapies in EHE, an ultra-rare sarcoma, marked by WWTR1-CAMTA1 or YAP1-TFE3 fusions. METHODS: Twenty sarcoma reference centres contributed data. Patients with advanced EHE diagnosed from 2000 onwards and treated with systemic therapies, were selected. Local pathologic review and molecular confirmation were required. Radiological response was retrospectively assessed by local investigators according to RECIST. Progression free survival (PFS) and overall survival (OS) were estimated by Kaplan-Meier method. RESULTS: Overall, 73 patients were included; 21 had more than one treatment. Thirty-three patients received anthracyclines regimens, achieving 1 (3%) partial response (PR), 25 (76%) stable disease (SD), 7 (21%) progressive disease (PD). The median (m-) PFS and m-OS were 5.5 and 14.3 months respectively. Eleven patients received paclitaxel, achieving 1 (9%) PR, 6 (55%) SD, 4 (36%) PD. The m-PFS and m-OS were 2.9 and 18.6 months, respectively. Twelve patients received pazopanib, achieving 3 (25%) SD, 9 (75%) PD. The m-PFS and m-OS were.2.9 and 8.5 months, respectively. Fifteen patients received INF-α 2b, achieving 1 (7%) PR, 11 (73%) SD, 3 (20%) PD. The m-PFS and m-OS were 8.9 months and 64.3, respectively. Among 27 patients treated with other regimens, 1 PR (ifosfamide) and 9 SD (5 gemcitabine +docetaxel, 2 oral cyclophosphamide, 2 others) were reported. CONCLUSION: Systemic therapies available for advanced sarcomas have limited activity in EHE. The identification of new active compounds, especially for rapidly progressive cases, is acutely needed.

Activity of sirolimus in patients with progressive epithelioid hemangioendothelioma: A case-series analysis within the Italian Rare Cancer Network.

BACKGROUND: The objective of this study was to report on a retrospective series of patients with epithelioid hemangioendothelioma (EHE) who received treatment with sirolimus within the Italian Rare Cancer Network. METHODS: From January 2005, 38 adult patients with advanced EHE received continuous-dosing sirolimus, 5 mg daily, until they developed either toxicity or disease progression. Disease progression in the 6 months before the start of treatment was required. Each pathologic diagnosis was reviewed. The daily dose of sirolimus was adjusted based on plasma levels. Response was retrospectively assessed by local investigators using Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST). Survival was estimated using the Kaplan-Meier method. RESULTS: All 38 patients (WW Domain Containing Transcription Regulator 1 [WWTR1]-positive, n = 37; transcription factor E3 [TFE3]-positive, n = 1) had disease progression before starting sirolimus (at baseline, 13 of 38 patients had the presence of serosal effusions and systemic symptoms). Thirty-seven patients were evaluable for response (there was 1 early interruption). The best RECIST responses were a partial response in 4 patients (10.8%), stable disease in 28 patients (75.7%), and disease progression in 5 patients (13.5%). At a 41.5-month median follow-up (interquartile range [IQR], 23.9-56.8 months), the median PFS was 13 months (95% CI, 3.7 months to not estimated [NE]), and the median OS was 18.8 months (95% CI, 10.6 months to NE). In patients who had serosal effusions at baseline, the median PFS was 4.8 months (IQR, 3.5-11.7 months), and the median OS was 10.6 months (IQR, 5.1-13.0 months), compared with 47.8 months (IQR, 11.4 months to NE) and 47.8 months (IQR, 15.7 months to NE), respectively, in patients without serosal effusions. Overall, sirolimus was fairly well tolerated, with 10 patients reporting irregular menstruation/ovary disfunction. CONCLUSIONS: The current results confirm that sirolimus is active in EHE, leading to prolonged stabilization in most patients who present without serosal effusions. Serosal effusions are confirmed as an unfavorable prognostic sign associated with short survival, and sirolimus displays limited activity in this subgroup.