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.

The patient perspective on sirolimus for epithelioid hemangioendothelioma (EHE): results of a community survey highlighting the importance of equitable access to treatments.

Background: Epithelioid hemangioendothelioma (EHE) is an ultra-rare, vascular sarcoma with clinical presentation ranging from an indolent to an aggressive form. Over 50% of patients present with metastatic disease, requiring systemic therapy, although no systemic therapies are specifically approved for EHE. Retrospective evidence supports the activity of mTOR inhibitors (e.g. sirolimus), although available only off-label. EHE patients and advocates are therefore working to support approval of effective treatments by collecting data on patient perspectives and experiences. Materials and methods: In February 2023, the EHE Rare Cancer Charity (UK) and The EHE Foundation (US), with other advocates, conducted a survey of perspectives and experiences of EHE patients regarding the use and accessibility of sirolimus. The survey consisted of 20 questions designed for individuals undergoing treatment, those who had been treated, or had never been treated with the drug. Widely promoted within the patient community, the online survey categorized patients into three cohorts for the analysis: liver transplant patients, non-transplant patients who had ever taken sirolimus and sirolimus-naïve non-transplant patients. Results: The survey evaluated data from 129 patient responses from 21 countries, mostly from USA, UK, Australia, and Canada (70%). The liver transplant, sirolimus and non-sirolimus cohorts were 16%, 25% and 59%, respectively. In the sirolimus group 66% reported treatment durations exceeding one year, with 16% exceeding five years, indicating the drug's efficacy. In the non-sirolimus group, the drug was not available for 42% and for 11% sirolimus was available but not selected for treatment because of its off-label status. Overall, 87% of all patients across all cohorts expressed the importance of the drug's availability as hugely or very important. Conclusion: The survey responses highlight the activity of sirolimus for EHE and the importance of securing a label extension for the drug delivering equitable access to this treatment for patients.

Guideline-Based Follow-Up Outcomes in Patients With Gastrointestinal Stromal Tumor With Low Risk of Recurrence: A Report From the Italian Sarcoma Group.

Importance: Gastrointestinal stromal tumor (GIST) follow-up is recommended by international guidelines, but data on the role of follow-up in patients with low relapse risk are missing. For these patients, the potential benefit of anticipating recurrence detection should be weighed against psychological burden and radiologic examination loads in terms of costs and radiation exposure. Objective: To evaluate the outcomes of guideline-based follow-up in low-risk GIST. Design, Setting, and Participants: This multi-institutional retrospective cohort study involving Italian Sarcoma Group reference institutions evaluated patients with GIST who underwent surgery between January 2001 and June 2019. Median follow-up time was 69.2 months. Data analysis was performed from December 15, 2022, to March 20, 2023. Patients with GIST at low risk according to Armed Forces Institute of Pathology criteria were included provided adequate clinical information was available: primary site, size, mitotic index, surgical margins, and 2 or more years of follow-up. Exposures: All patients underwent follow-up according to European Society for Medical Oncology (ESMO) guidelines. Main Outcomes and Measures: The primary outcome was the number of tests needed to identify a relapse according to ESMO guidelines follow-up plan. Secondary outcomes included relapse rate, relapse timing, disease-free survival (DFS), overall survival (OS), GIST-specific survival (GIST-SS), postrelapse OS, secondary tumor rates, and theoretical ionizing radiation exposure. An exploratory end point, new follow-up schedule proposal for patients with low-risk GIST according to the observed results, was also assessed. Results: A total of 737 patients (377 men [51.2%]; median age at diagnosis, 63 [range, 18-86] years) with low-risk GIST were included. Estimated 5-year survival rates were 95.5% for DFS, 99.8% for GIST-SS, and 96.1% for OS. Estimated 10-year survival rates were 93.4% for DFS, 98.1% for GIST-SS, and 91.0% for OS. Forty-two patients (5.7%) experienced disease relapse during follow-up (9 local, 31 distant, 2 both), of which 9 were detected after 10 or more years. This translated into approximately 1 relapse detected for every 170 computed tomography scans performed, with a median radiation exposure of 80 (IQR, 32-112) mSv per patient. Nongastric primary tumor (hazard ratio [HR], 2.09; 95% CI, 1.14-3.83; P = .02), and KIT mutation (HR, 2.77; 95% CI, 1.05-7.27; P = .04) were associated with a higher risk of relapse. Second tumors affected 187 of 737 patients (25%), of which 56 were detected during follow-up and represented the primary cause of death in these patients. Conclusions and Relevance: In this cohort study on patients affected by low-risk GISTs, the risk of relapse was low despite a follow-up across 10 or more years. These data suggest the need to revise follow-up schedules to reduce the anxiety, costs, and radiation exposure of currently recommended follow-up strategy.

Regorafenib in advanced solitary fibrous tumour: Results from an exploratory phase II clinical study.

BACKGROUND: To investigate the activity of regorafenib in advanced solitary fibrous tumour (SFT). METHODS: An Italian monocentric investigator-initiated exploratory single-arm Phase II trial was conducted of regorafenib in adult patients with advanced and progressive SFT, until progression or limiting toxicity. Prior treatment with antiangiogenics was allowed. Primary and secondary end-points were: overall response rate (ORR) by Choi criteria, and ORR by RECIST, progression-free survival (PFS), overall survival (OS). RESULTS: From January 2016 to February 2021, 18 patients were enroled [malignant-SFT = 13; dedifferentiated-SFT (D-SFT) = 4; typical-SFT (T-SFT) = 1]. Fourteen patients were pre-treated, in 12 cases with antiangiogenics (median [m-] lines of treatment = 3). Sixteen patients were evaluable for response (one screening failure; one early discontinuation). Six/16 (35.2%) required a definitive dose reduction. ORR by Choi was 37.5% (95% CI: 15.2-64.6), with 6/16 (37.5%) partial responses (PR), 6/16 (37.5%) stable disease (SD) and 4/16 (25%) progressions; 5/6 responses occurred in patients pre-treated with antiangiogenics. No responses were detected in D-SFT. Best RECIST responses were: 1/16 (6.2%) PR, 12/16 (75%) SD, 3/16 (18.8%) progressions. At 48.4 month m-FU, m-PFS by Choi was 4.7 (inter-quartile range: 2.4-13.1) months, with 31.2% patients progression-free at 1 year. CONCLUSION: Regorafenib showed activity in SFT, with 30% patients free-from-progression at one year. Responses were observed also in patients pretreated and refractory to another antiangiogenic agents. However, ORR and m-PFS were lower than reported with other antiangiogenics, and this was possibly due to discrepancies in the patient population and the high-rate of dose reductions.

The rare entity of gastrointestinal leiomyosarcomas: An Italian multicenter retrospective study in high-volume referral centers.

BACKGROUND: After a huge efficacy of imatinib in treating patients with gastrointestinal stromal tumors (GISTs) was proven, a maximum effort was made to make a differential diagnosis between GISTs and gastrointestinal leiomyosarcomas (GI-LMS), showing the latter to be an extremely rare tumor entity. Limited data on GI-LMS biology, clinical behavior and drug-sensibility are available, and the clinical decision-making in this subgroup of patients is usually challenging. METHODS: We conducted a multicenter, retrospective observational study on patients with diagnosed GI-LMS from 2004 to 2020 within six high-volume referral centers in Italy. RESULTS: Thirty-three patients had diagnosis of KIT-negative GI-LMS confirmed by sarcoma-expert pathologist. The most common site of origin was the intestine. Twenty-two patients had localized disease and underwent surgery: with a median follow-up of 72 months, median disease-free survival was 42 months. Overall survival (OS)-rate at 5 years was 73% and median OS was 193 months. Five out of 10 patients with local relapse received a salvage surgery, and 2/5 remained with no evidence of disease. Thirteen patients received neoadjuvant (6) or adjuvant (7) chemotherapy, and 2/13 patients remained free from relapse. The median OS for patients with metastatic LMS was 16.4 months. CONCLUSION: GI-LMS is very rare and extremely aggressive subgroup of sarcomas with a high tendency to systemic spread. Localized GI-LMS at diagnosis may be cured if treated with adequate surgery with or without (neo) adjuvant chemotherapy, while de-novo metastatic disease appeared to have a poor prognosis. Clinical effort to understand GI-LMS biology and clinical behavior and to develop active treatment strategy, especially for metastatic-disease, is warranted.

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.

EJSO educational Special issue from the TARPSWG - Standard medical treatment and new options in retroperitoneal sarcoma.

Retroperitoneal soft tissue sarcomas mainly consist histologically of liposarcomas and leiomyosarcomas. For the liposarcoma subgroup, the local relapse rate seems to determine patients' overall prognosis. In contrast, leiomyosarcoma patients are challenged by the development of metastatic disease; therefore, effective systemic therapies are the cornerstone to improve patients' outcome. No doubt, the limited number of active regimens currently available makes the treatment of patients with locally advanced and/or metastatic disease challenging and results in the overall poor prognosis of this population. In this European Journal of Surgical Oncology Educational Special Issue from the Transatlantic Australasian RetroPeritoneal Sarcoma Working Group (TARPSWG), we aim to summarize state-of-the-art systemic treatments for patients with retroperitoneal sarcomas with a focus on the locally advanced and metastatic disease setting including conventional standard chemotherapies as well as new innovative treatment approaches in order to identify current unmet medical needs guiding the sarcoma community to initiate appropriate translational research projects and design innovative clinical trials.

Primary pleural epithelioid hemangioendothelioma: case report and review of the literature.

Epithelioid hemangioendothelioma (EHE) is an extremely rare vascular sarcoma with an unpredictable clinical behavior. Pleural EHEs have been associated with poor response to treatment and reduced survival. To date, no standard treatment for EHE is available. Here we report the case of a 53-year-old man who underwent radical surgery for a symptomatic primary pleural EHE. Clinical presentation was characterized by chronic pain in the left hemithorax with transitory flare, anemia, weight loss and progressive worsening of clinical conditions. After surgery, he resumed active life and normal daily activities and, at 8 months, 18F-FDG PET and computed tomography scan showed no radiological evidence of recurrent disease. Clinical signs of this rare disease, histological features, imaging findings and functional imaging are discussed. We also report a summary of other cases with resected pleural EHE and we briefly review the role of chemotherapeutic, immunomodulatory and antiangiogenic drugs for advanced disease.

Magnetic resonance imaging patterns of tumor response to chemotherapy in desmoid-type fibromatosis.

BACKGROUND: We aimed to investigate changes in volume and MRI T2-weighted intensity in desmoid-type fibromatosis (DF) receiving methotrexate plus vinca-alkaloids (MTX-VA) at Istituto Nazionale dei Tumori, Milan. METHODS: All cases of sporadic DF treated with MTX-VA from 1999 to 2019 were reviewed. MRIs at baseline, 6 and 12 months of chemotherapy and at treatment withdrawal were retrospectively reviewed, contouring the tumor lesion and measuring diameters, volume, and mean T2-signal intensity (normalized to muscle) changes. These parameters were also evaluated according to clinical variables. RESULTS: Thirty-two DF patients were identified. Best RECIST response was: 25% partial response, 69% stable disease, 6% progression. A ≥65% tumor volume reduction was observed in 38%, <65% reduction in 53%, an increase in 9%. 22% had RECIST stable disease with a ≥65% tumor volume reduction. T2-signal intensity decreased by ≥50% in 47%, <50% in 41% and increased in 12%. In patients with symptomatic improvement while on therapy and in patients maintaining symptomatic improvement during follow-up, median T2-signal intensity showed a reduction along the time points (3.0, 1.9, 1.2, 1.1; 2.9, 2.0, 1.2, 1.2, respectively); in patients without symptomatic improvement and in those clinically progressing during follow-up, a reduction was not observed. High T2-signal intensity at baseline was observed in patients showing RECIST progression during follow-up. CONCLUSIONS: In this series, RECIST detected a lower proportion of responses as compared to volumetric and T2-signal changes. T2-signal reduction seemed to better reflect symptomatic improvement. High T2-signal intensity at baseline was related to a higher proportion of further progression.

Extraskeletal Myxoid Chondrosarcoma: State of the Art and Current Research on Biology and Clinical Management.

Extraskeletal myxoid chondrosarcoma (EMC) is an ultra-rare mesenchymal neoplasm with uncertain differentiation, which arises mostly in the deep soft tissue of proximal extremities and limb girdles. EMC is marked by a translocation involving the NR4A3 gene, which can be fused in-frame with different partners, most often EWSR1 or TAF1. Although EMC biology is still poorly defined, recent studies have started shedding light on the specific contribution of NR4A3 chimeric proteins to EMC pathogenesis and clinical outcome. Standard treatment for localized disease is surgery, plus or minus radiation therapy with an expected prolonged survival even though the risk of relapse is about 50%. In advanced cases, besides the standard chemotherapy currently used for soft tissue sarcoma, antiangiogenic agents have recently shown promising activity. The aim of this review is to provide the state of the art of treatment for localized and advanced disease, with a focus on pharmacological treatments available for EMC. The biological basis of current research and future perspectives will be also discussed.

Pharmacokinetics, safety, and activity of trabectedin as first-line treatment in elderly patients who are affected by advanced sarcoma and are unfit to receive standard chemotherapy: A phase 2 study (TR1US study) from the Italian Sarcoma Group.

BACKGROUND: Although elderly patients (≥70 years) represent 30% of new diagnoses of soft tissue sarcoma (STS), they are underrepresented in clinical trials and are often unfit to receive standard anthracycline-based chemotherapy. Trabectedin is registered as a second-line treatment for advanced STS and is characterized by a favorable safety profile. METHODS: The aim of this single-arm, phase 2 study was to investigate trabectedin (scheduled dose, 1.3-1.5 mg/m2 ) as a first-line treatment in elderly patients with advanced stage STS who are inoperable and are unfit to receive standard anthracycline-based chemotherapy. The coprimary endpoints were progression-free survival at 3 months (PFS3) and the rate of clinically limiting toxicities (CLTs). We also conducted an ancillary study on pharmacokinetics. RESULTS: Twenty-four patients (12 men and 12 women) with a median age of 79 years (interquartile range [IQR], 74-83 years) were enrolled. The histological subtype was leiomyosarcoma in 46%, liposarcoma in 33%, and other histotypes in 21%. The median number of trabectedin courses was 4 (IQR, 3-6), with 7 patients (29%) receiving ≥6 cycles. Eight patients (33%) required dose reductions. The most frequent grade 3/4 adverse events were neutropenia in 9 patients (38%), fatigue in 5 patients (21%), and aminotransferase elevation in 5 patients (21%). PFS3, median PFS, and overall survival were 71% (80% CI, 57%-81%), 4 months, and 12 months, respectively. Ten patients (42% [80% CI, 28%-57%]) experienced CLTs. Trabectedin Cmax , half-life, clearance, and distribution volume were 1.28 ng/mL (standard deviation [SD], 0.58 ng/mL), 26.70 hours (SD, 9.09 hours), 39.98 L/h/m2 (SD, 14.08 L/h/m2 ), and 1460 L/m2 (SD, 561 L/m2 ), respectively. CONCLUSION: Trabectedin can be administered safely to elderly patients with STS who are unfit to receive anthracyclines. Pharmacokinetics in the elderly population was superimposable to historical data.

The Activity of Chemotherapy in Inflammatory Myofibroblastic Tumors: A Multicenter, European Retrospective Case Series Analysis.

BACKGROUND: This study aimed to review the activity of cytotoxic chemotherapy in patients with inflammatory myofibroblastic tumors (IMTs) treated at nine European sarcoma reference centers. MATERIALS AND METHODS: Patients of any age, with histologically proven IMT, treated with anthracycline-based methotrexate plus/minus vinorelbine/vinblastine (MTX-V) or other chemotherapeutic regimens between 1996 and 2018 were retrospectively reviewed. Diagnosis was confirmed at the local level by an expert pathologist. Response was retrospectively assessed by local investigators by RECIST v1.1. Progression-free survival (PFS), relapse-free survival (RFS), and overall survival (OS) were computed by Kaplan-Meier method. RESULTS: Thirty-eight patients were included. Twenty-five patients (8 localized, 17 advanced disease) received an anthracycline-based regimen; 21 were evaluable for response. Overall response rate (ORR) was 10/21 (47.6%). At a 70.8-month median follow-up (FU), median RFS and median OS were not reached (NR) in patients with localized disease; median PFS and median OS were 6.3 (interquartile range [IQR]: 1.9-13.4) and 21.2 (IQR: 7.7-40.7) months in patients with advanced disease. Thirteen patients received MTX-V (4 localized, 9 advanced disease), all evaluable for response. ORR was 7/13 (53.8%). At a 56.6-month median FU, median RFS and median OS were 42.5 (IQR: 12.9-61.2) months and NR (no death events) in patients with localized disease, and NR (IQR: 24.9 to NR) and 83.4 months (IQR: 83.4 to NR) in patients with advanced disease. In the "other-regimens group," responses were seen in 3/4 patients treated with oral cyclophosphamide and 1/2 with docetaxel/gemcitabine. CONCLUSION: Anthracycline-based and MTX-V regimens are very effective in IMT, with a similar ORR in both groups. MTX-V achieved a prolonged disease control. Responses were also seen with oral cyclophosphamide and docetaxel/gemcitabine, but few patients were treated with these schedules. IMPLICATIONS FOR PRACTICE: Inflammatory myofibroblastic tumor (IMT) is an ultrarare sarcoma with known sensitivity to anaplastic lymphoma kinase (ALK) inhibitors in ALK-fused cases, although ALK inhibitors are not licensed in the disease. The current knowledge on the activity of cytotoxic chemotherapy is limited. This multi-institutional retrospective study on pediatric and adult patients with IMT shows that cytotoxic chemotherapy, and in particular anthracycline-based and methotrexate plus/minus vinorelbine/vinblastine regimens, represents a treatment option and can be considered in IMT patients irrespectively from ALK status. This study provides a benchmark for future studies on new medical therapies.

Pexidartinib for the treatment of adult symptomatic patients with tenosynovial giant cell tumors.

INTRODUCTION: Tenosynovial giant cell tumor (TGCT) is a benign mesenchymal tumor arising from the synovium of tendon sheats and joints, driven by colony-stimulating factor 1 (CSF1) over-expression. Standard treatment is surgery, but local recurrences are frequent, especially in diffuse TGCT subtype, rarely cured with surgery. When TGCT becomes a chronic condition, which may severely compromise joint function and quality of life, patients may need a systemic therapy. Areas covered: We reviewed the drugs on clinical development in TGCT, focusing on the pharmacodynamics, pharmacokinetics, efficacy, and toxicity profile of pexidartinib, the first drug approved in the US for TGCT, and on the open questions about its optimal use in clinical practice. EXPERT OPINION: CSFR1 inhibitors have opened a new avenue for treatment of TGCT patients. Pexidartinib is the first-in-class FDA approved agent for symptomatic locally advanced TGCT, based on a phase III study where pexidartinib showed high anti-tumor activity, improved patient symptoms, and functional outcome. A few cases of potentially life-threatening hepatic toxicity were observed. TGCT patients candidate to pexidartinib need to be carefully selected by the multidisciplinary board of center of expertise, balancing the expected risk-benefit ratio. Close monitoring of liver function and adequate education on the approved indication is warranted.

The natural history of epithelioid sarcoma. A retrospective multicentre case-series within the Italian Sarcoma Group.

INTRODUCTION: This case-series is aimed to describe the natural history of epithelioid sarcoma (ES) and to provide insights into the differential clinical behaviour of its two variants ("classic-type" and "proximal-type"). The value of a subtype-adapted grading system based on pathological features is explored. METHODS: Data from consecutive, primary, localised, INI1-deleted ES operated at three Italian sarcoma reference centres (1995-2015) were included. Centralised pathological review was performed. Classic-type ES was broken down into "high-grade" and "low-grade", according to number of mitoses, evidence of necrosis and nuclear atypia. Five- and 10-year overall survival (OS) and crude cumulative incidence (CCI) of local recurrence (LR) and distant metastasis (DM) were estimated. RESULTS: Fifty-two patients were included. 5- and 10-year OS estimates were 70% and 47% in the whole series, 57% and 37% in patients with proximal-type ES, 77% and 54% in patients with classic-type ES (P = 0.02). In classic-type ES, 5- and 10-year OS was higher for low-grade (95% and 72%, respectively) than high-grade tumours (P = 0.002). 5- and 10-year CCI estimates for LR were 21% and 33% in the whole series. 5- and 10-year CCI estimates for DM were 35% and 39% in the whole series, both 28% in classic-type ES, 47% and 59% in proximal-type ES (P = 0.03). CONCLUSIONS: Suffering from a proximal- or a classic-type is the stronger predictor of outcome in patients with localised ES, with proximal-type ES patients having lower survival due to a higher tendency toward metastatic spreading. However, the "high-grade" classic-type ES was associated with outcomes close to proximal-type ES.

Soft tissue sarcoma in Italy: From epidemiological data to clinical networking to improve patient care and outcomes.

Sarcomas are rare malignant neoplasms that develop from mesenchymal cells and include a heterogeneous and large group of histological subtypes that may occur at any anatomical site. Soft tissue sarcomas (STS), the focus of this review, account for ≈70‒80% of sarcomas and represent <1% of all cancers. The heterogeneity of STS applies to both their topography and morphology, and 5-year survival can vary widely depending on disease stage and the complex interplay between anatomical site and histology for different STS subtypes. The rarity and heterogeneity of STS, together with other factors, such as the lack of clinical expertise often lead to difficulties and delays in making an accurate diagnosis and to the inappropriate management of each STS subtype. Therefore, this group of cancers requires special attention and approaches to diagnosis and treatment. Epidemiological data on STS are limited, and concerns have been raised regarding accurate registration of STS in cancer registries, including issues related to details of the histotypes. This review provides an overview of the epidemiology of STS in Italy, focusing on data from the Italian Association of Cancer Registries (AIRTUM), and compares findings with those from other European countries. Based on these data, and considering that STS is among the most common group of rare cancers, the relevance of multidisciplinary care for STS patients through reference centres, clinical networks and collaborative disease-specific groups is discussed.

Denosumab treatment of inoperable or locally advanced giant cell tumor of bone - Multicenter analysis outside clinical trial.

BACKGROUND: Giant cell tumor of bone (GCTB) is an osteolytic, locally aggressive, rarely metastazing bone tumor. This is a retrospective study evaluating a large series of GCTB patients treated with denosumab in routine practice in 6 European reference centers. METHODS: Patients with locally advanced, unresectable or metastatic GCTB, treated with denosumab outside clinical trials were eligible. Primary end-point was progression-free survival (PFS) for all patients; secondary end-points were: type of surgery, relapse rate and event-free survival for patients after preoperative denosumab + surgery. RESULTS: We identified 138 patients treated in the period 2011-2016. In 40/43 cases the diagnosis was confirmed by H3F3A gene mutation. Median follow-up time was 23 months (range 6-48). Primary tumor was located in lower limb (38%) - mostly in femur and tibia, in upper limb (34%), and in pelvis/axial skeleton/ribs (28%). 110 (80%) patients had primary tumors, 28 (22%) recurrent tumors after previous surgical procedures (+/- radiotherapy). 89/138 patients had locally advanced GCTB and underwent neoadjuvant denosumab. The median denosumab treatment duration was 8 months (median number of cycles 11), 98% had clinical benefit from therapy. 39 (44%) had wide en-bloc resection - WE (+implantation of the prosthesis in 17 cases), the other 50 (56%) cases had intralesional curettage - C. Progression after surgical treatment was observed in 19 patients, 16 of them after C (32%); 13 patients underwent denosumab re-challenge, and all responded. Two-year progression-free survival (PFS; from denosumab start) rate was 81%; 2-year EventFS (from surgery) was significantly better in WE group (93%) vs 55% in C group (p = 0.006). Treatment was well tolerated with only 2 cases of grade 3 toxicity and one osteonecrosis of the jaw. CONCLUSION: Our retrospective study confirms that denosumab is extremely efficient in unresectable/metastatic disease as well as in a neoadjuvant setting. Our data confirm excellent efficacy and short-term tolerability of this drug. Our data suggest that neoadjuvant therapy with denosumab is the option for treatment of initially locally advanced tumors to facilitate complete surgical resection or avoid mutilating surgery. The risk of recurrences after curettage of GCTB following denosumab raises questions about the optimal management of such cases.

Denosumab treated giant cell tumour of bone: a morphological, immunohistochemical and molecular analysis of a series.

AIMS: Denosumab, a fully human monoclonal antibody directed against RANKL, has recently been introduced in the treatment strategy of giant cell tumour of bone (GCTB). Aim of this study was to investigate the phenotypical modifications induced by denosumab treatment in a series of 15 GCTB. METHODS: The tumours were characterised for histone 3.3 mutations, and studied immunohistochemically for the modifications of RANKL, RANK, SATB2 and RUNX2 expression, as well as of tumour proliferative activity and angiogenesis. RESULTS: Nine of 11 tumours investigated presented a histone 3.3 mutation in H3F3A, and 2 of these for which the analysis was carried out in pretreatment and post-treatment specimens showed the same mutation in both. Denosumab induced the disappearance of osteoclast-like giant cells, leaving residual spindle neoplastic cells arranged in a storiform pattern, with deposition of trabecular collagen matrix and osteoid, which tended to maturation in the peripheral portions of the lesion. RANK and RANKL expression was variable, with no significant variation after treatment. Moreover, we did not observe any significant modification of the expression of the osteoblastic markers SATB2 and RUNX2. Denosumab treatment determined a significant reduction of the proliferative index and of tumour angiogenesis (p=0.001, Wilcoxon rank-sum test). CONCLUSIONS: These results indicate that denosumab induces a partial maturation towards the osteoblastic phenotype of the neoplastic cells of GCTB, with production of fibrous and osteoid matrix, but with minor immunophenotypical changes. Finally, we first report an antiangiogenic activity of denosumab in GCTB, possibly mediated by a RANKL-dependent pathway.

Small-bowel neuroendocrine tumor and retroperitoneal fibrosis: efficacy of octreotide and tamoxifen.

AIMS AND BACKGROUND: Neuroendocrine tumors are uncommon clinical entities and only a few cases of the co-occurrence of neuroendocrine tumors and retroperitoneal fibrosis have been described in the literature. METHODS AND STUDY DESIGN: We report the promising results achieved in a case of neuroendocrine tumor complicated by retroperitoneal fibrosis causing right ureteral obstruction treated with long-acting release octreotide and tamoxifen. RESULTS AND CONCLUSIONS: The treatment resulted in a complete response without toxicity.