Real-world outcomes of metastatic clear cell sarcoma sequential chemotherapy.

Clear cell sarcoma is an ultra-rare chemoresistant subtype of soft tissue sarcoma. This retrospective analysis aimed to clarify the efficacy of palliative chemotherapy in CCS by assessing response rates, progression-free survival (PFS), and overall survival (OS) at a referral center. A retrospective analysis of palliative treatment was conducted on patients with CCS treated at the sarcoma unit from 1997 to 2023. Treatment responses were assessed using RECIST criteria, and the Kaplan-Meier method was used to calculate PFS and OS. The analysis covered 23 CCS chemotherapy-treated patients with 11 (47.8%) men. The median age at the palliative treatment start was 32 years (range 18-59). The median follow-up was 8.2 months. Four patients were referred to our centre for M1 disease, and 6 received perioperative chemotherapy and progressed during follow-up. In the first line, 14 patients received anthracycline-based chemotherapy (60.9%), five were treated with ifosfamide (HD-IFO), and four received other regimens. One patient (4.3%) achieved partial response (PR), and 12 patients (52.2%) achieved stable disease (SD) as the best response. Median PFS in 1 line was 2.79 months (95% CI: 2.04-8.38), and 1.76 months (95% CI: 0.72-6.97) in the second line. The median OS from first-line palliative chemotherapy was 8.2 months (95% CI: 6.2-14), and the second-line palliative chemotherapy mOS was 4.6 months (95% CI: 3.9-NA). Perioperatively anthracycline-pretreated worsened patients' median PFS in the M1 setting. Poor responses to conventional chemotherapy were observed in CCS, indicating a need for further clinical trials in this indication.

Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment.

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with intermediate malignancy characterized by a propensity for recurrence but a low metastatic rate. Diagnostic challenges arise from the diverse pathological presentation, variable symptomatology, and lack of different imaging features. However, IMT is identified by the fusion of the anaplastic lymphoma kinase (ALK) gene, which is present in approximately 70% of cases, with various fusion partners, including ran-binding protein 2 (RANBP2), which allows confirmation of the diagnosis. While surgery is the preferred approach for localized tumors, the optimal long-term treatment for advanced or metastatic disease is difficult to define. Targeted therapies are crucial for achieving sustained response to treatment within the context of genetic alteration in IMT. Crizotinib, an ALK tyrosine kinase inhibitor (TKI), was officially approved by the US Food and Drug Administration (FDA) in 2020 to treat IMT with ALK rearrangement. However, most patients face resistance and disease progression, requiring consideration of sequential treatments. Combining radiotherapy with targeted therapy appears to be beneficial in this indication. Early promising results have also been achieved with immunotherapy, indicating potential for combined therapy approaches. However, defined recommendations are still lacking. This review analyzes the available research on IMT, including genetic disorders and their impact on the course of the disease, data on the latest targeted therapy regimens and the possibility of developing immunotherapy in this indication, as well as summarizing general knowledge about prognostic and predictive factors, also in terms of resistance to systemic therapy.

Long-term efficacy of neoadjuvant-adjuvant targeted therapy in borderline resectable stage IIIB-D and IV melanoma.

BACKGROUND: Neoadjuvant-adjuvant therapy for locally advanced or potentially resectable metastatic melanoma was expected to improve operability and clinical outcomes over upfront surgery and adjuvant treatment only. METHODS: Forty-seven consecutive patients were treated with neoadjuvant-adjuvant BRAF inhibitors (BRAFi)/MEK inhibitors (MEKi) and surgery. RESULTS: Twelve (26%) patients achieved a pathological complete response and 10 (21%) patients achieved a near-complete response. In the whole group, median recurrence-free survival was 19.4 months and median distant metastasis-free survival (mDMFS) was 21.9 months. In patients with a pathological complete response (pCR)/near-pCR median recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) were significantly longer than in patients with minor pathological response with hazard ratio (HR) = 0.37 (p = .005) for RFS and HR = 0.33 (p = .002) for DMFS. After median follow-up of 52.5 months, median progression-free survival since BRAFi/MEKi therapy initiation was 25.1 months. The median time-to-treatment-failure since initiation of neoadjuvant therapy was 22.2 months and was significantly longer in patients with pCR/near-pCR (HR = 0.45; p = .022). Neoadjuvant therapy did not result in any new specific complications of surgery. After 48 months, RFS and overall survival were 36.3% and 64.8% or 20% and 37.4% in patients with pCR/near-pCR and pathological partial response/pathological nonresponse, respectively. CONCLUSIONS: The authors confirmed that BRAFi/MEKi combination is an effective and safe regimen in the perioperative treatment of stage III/IV melanoma. Major pathological response to neoadjuvant treatment is a surrogate marker of recurrence including DMFS in these patients. PLAIN LANGUAGE SUMMARY: Our study presents a large comprehensive analysis of neoadjuvant-adjuvant systemic therapy in patients diagnosed with marginally resectable stage III or IV melanoma. Neoadjuvant therapy effectively reduced the volume of the disease, which facilitated subsequent surgical resection. After median follow-up of 52.5 months, median progression-free survival since therapy initiation was 25.1 months. Twelve patients had complete pathological response and 10 patients had a near-complete pathological response-and together they had median recurrence-free survival and distant metastasis-free survival significantly longer than in patients with pathological partial response or nonresponse. Complete/near-complete pathological response to neoadjuvant treatment is a surrogate marker of recurrence-free, including distant metastasis-free, survival in these patients.

Preoperative-postoperative immunotherapy as treatment of borderline resectable and oligoprogressive stage III B-D and IV melanoma.

INTRODUCTION: Perioperative therapy has gained significant importance in patients with advanced melanoma. Currently, there is little data on the routine use of preoperative immunotherapy in metastatic melanoma outside clinical trials. This study aimed to evaluate the effectiveness of preoperative treatment in patients with borderline resectable stage III or IV melanoma as well as in oligoprogressing stage IV cases; the secondary aim is to describe the safety of surgery after immunotherapy. MATERIALS AND METHODS: Since 1/Jan/2016 seventeen patients were treated with curative intent neoadjuvant immunotherapy, surgery, and adjuvant immunotherapy, while nineteen patients were operated due to oligoprogression while treted with immunotherapy. Survival was analyzed using the Kaplan-Meier method and association between variables was tested using the chi-squared test. RESULTS: R0 resection was achieved in 76.5 % of cases after neoadjuvant immunotherapy. 24 % of patients achieved objective RECIST response and 35 % complete or major pathological response. At the median follow-up time of 51.4 months, 64.7 % of patients were free of PD after perioperative treatment, while 3-year RFS and OS rates were 68 % and 80.9 %, respectively. R0 resection was achieved in 73.7 % of oligo-progressing nodules. The median time to PD on immunotherapy after the first oligoprogression was 10.3 months. Immunotherapy did not result in any unexpected surgical complications. No patient died during preoperative treatment due to immunotherapy toxicity or disease progression. CONCLUSIONS: We confirmed treatment safety and long-term disease control after perioperative immunotherapy. Patients with borderline resectable melanoma should be referred to reference centers using neoadjuvant immunotherapy.

Diagnostics and Treatment of Extrameningeal Solitary Fibrous Tumors.

Solitary fibrous tumors (SFT) are rare mesenchymal neoplasms that account for less than 2% of all soft tissue masses. In the latest WHO 2020 Classification of Soft Tissue Tumors, extrameningeal SFT was listed as intermediate (rarely metastasizing) or malignant neoplasms. Due to the lack of characteristic clinical features, their diagnosis and treatment remain challenging. The pathogenesis of SFT is often associated with the presence of fusions of the NAB2-STAT6 gene on the 12q13 chromosome. Cytoplasmic CD34 positive staining is considerably characteristic for most SFTs; less frequently, factor XII, vimentin, bcl-2, and CD99 are present. A key factor in the diagnosis is the prevalent nuclear location of STAT6 expression. Radical resection is the mainstay of localized SFTs. In the case of unresectable disease, only radiotherapy or radio-chemotherapy may significantly ensure long-term local control of primary and metastatic lesions. To date, no practical guidelines have been published for the treatment of advanced or metastatic disease. Classical anthracycline-based chemotherapy is applicable. The latest studies suggest that antiangiogenic therapies should be considered after first-line treatment. Other drugs, such as imatinib, figitumumab, axitinib, and eribulin, are also being tested. Definitive radiotherapy appears to be a promising therapeutic modality. Since standards for the treatment of advanced and metastatic diseases are not available, further investigation of novel agents is necessary.

Modern Approach to Melanoma Adjuvant Treatment with Anti-PD1 Immune Check Point Inhibitors or BRAF/MEK Targeted Therapy: Multicenter Real-World Report.

BACKGROUND: The landscape of melanoma management changed as randomized trials have launched adjuvant treatment. MATERIALS AND METHODS: An analysis of data on 248 consecutive melanoma stage III and IV patients given adjuvant therapy in eight centers (February 2019 to January 2021) was conducted. RESULTS: The analyzed cohort comprised 147 melanoma patients given anti-PD1 (33% nivolumab, 26% pembrolizumab), and 101 (41%) were given dabrafenib plus trametinib (DT). The 2-year overall survival (OS), relapse-free survival (RFS), and distant-metastases-free survival (DMFS) rates were 86.7%, 61.4%, and 70.2%, respectively. The disease stage affected only the RFS rate; for stage IV, it was 52.2% (95% CI: 33.4-81.5%) vs. 62.5% (95% CI: 52.3-74.8%) for IIIA-D, p = 0.0033. The type of lymph node surgery before adjuvant therapy did not influence the outcomes. Completion of lymph node dissection cessation after positive SLNB did not affect the results in terms of RFS or OS. Treatment-related adverse events (TRAE) were associated with longer 24-month RFS, with a rate of 68.7% (55.5-84.9%) for TRAE vs. 56.6% (45.8-70%) without TRAE, p = 0.0031. For TRAE of grade ≥ 3, a significant decline in OS to 60.6% (26.9-100%; p = 0.004) was observed. CONCLUSIONS: Melanoma adjuvant therapy with anti-PD1 or DT outside clinical trials appears to be effective and comparable with the results of registration studies. Our data support a de-escalating surgery approach in melanoma treatment.

Management Strategies for Adults with Locally Advanced, Unresectable or Metastatic Malignant Perivascular Epithelioid Cell Tumor (PEComa): Challenges and Solutions.

PEComa (PEC tumor; perivascular epithelioid cell tumors) is a rare group of tumors of mesenchymal origin composed of perivascular epithelioid cells (PEC) with features of melanotic and smooth muscle differentiation. In this article, we would like to present the current treatment options for this group of tumors. PEComas are classified as tumors of uncertain malignant potential because recurrences occur after radical treatment. The primary treatment is surgical resection with negative margins. Due to the different locations of the tumors, often the cooperation of multispecialty surgeons is required during the operations. In locally advanced cases, cytoreduction and HIPEC may be effective but still are an experimental treatment. For nonresectable PEComa chemotherapy, mTOR inhibitors and VEGFR inhibitors are used.

Long-Term Outcomes of Targeted Therapy after First-Line Immunotherapy in BRAF-Mutated Advanced Cutaneous Melanoma Patients-Real-World Evidence.

BACKGROUND: Currently, limited data on targeted therapy and immunotherapy sequencing in patients with BRAF-mutant melanoma is available. Targeted therapy and immunotherapy are expected to be comparable in terms of overall survival (OS) when used as second-line therapies; therefore, understanding the characteristics of patients who completed sequential treatment is needed. METHODS: The primary objective of this study was to analyze the efficacy of BRAFi/MEKi activity as second-line therapy in patients with advanced melanoma. We also aimed to describe the clinical characteristics of patients with advanced melanoma who were treated sequentially with immunotherapy and targeted therapy. We enrolled 97 patients treated between 1st December 2015 and 31st December 2020 with first-line immunotherapy with programmed cell death 1 (PD-1) checkpoint inhibitors; and for the second-line treatment with at least one cycle of BRAFi/MEKi therapy with follow-up through 31 January 2022. RESULTS: Median OS since first-line treatment initiation was 19.9 months and 12.8 months since initiation of BRAFi/MEKi treatment. All BRAFi/MRKi combinations were similarly effective. Median progression free survival (PFS) was 7.5 months since initiation of any BRAFi/MEKi treatment. CONCLUSIONS: BRAFi/MEKi therapy is effective in the second-line in advanced and metastatic melanoma patients. For the first time, the efficacy of all BRAFi/MEKi combinations as second-line therapy is shown.

The Use of ctDNA for BRAF Mutation Testing in Routine Clinical Practice in Patients with Advanced Melanoma.

Assessment of BRAF mutation status is mandatory in advanced, treatment-naïve melanoma patients. Liquid biopsy can be an alternative in cases with inadequate or unavailable tumor tissue. The aim of our study was to evaluate the clinical utility of plasma circulating tumor DNA analysis for BRAF mutation testing and to assess outcomes of therapy with BRAF/MEK inhibitors initiated based on the liquid biopsy results. This was a retrospective single-center analysis of 46 patients (21 female, 25 male) with advanced melanoma who underwent circulating tumor DNA (ctDNA) BRAF mutation testing. A BRAF mutation was found in 45.7% (21/46) of liquid biopsies and 44.8% (13/29) of tissue samples. In patients with both ctDNA and tissue samples (n = 29), the concordance between the results of both tests was 82.8%. A BRAF mutation was detected in 7/17 (41.2%) patients with only ctDNA analysis. In 18 patients, therapy with BRAF/MEK inhibitors was initiated on the basis of the result of liquid biopsy. The objective response rate was 77.8 %, and the median PFS was 6.0 months. Our study confirms the clinical utility of BRAF mutation detection in plasma ctDNA. This study provides initial real-world data showing that treatment with BRAF/MEK inhibitors could be commenced based on liquid biopsy results.

Treatment of Locally Advanced Merkel Cell Carcinoma-A Multi-Center Study.

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer with a high risk of recurrence and poor prognosis. The treatment of locally advanced disease involves surgery and radiotherapy. To analyze real-life treatment patterns and clinical outcomes, we conducted a retrospective analysis of data from 161 MCC patients treated with curative intent in four oncological centers in Poland. The median age at diagnosis was 72 years (30-94); 49.7% were male. Lymph node (LN) involvement at diagnosis was found in 26.9% of patients. Sentinel lymph node biopsy (SLNB) was performed in 36.5% of patients (positive in 10.5%), and 51.9% of patients received perioperative treatment. The relapse rate was 38.3%. With the median follow-up of 2.3 years, the median disease-free survival (DFS) was not reached, and the 1-year rate was 65%. The negative independent risk factors for DFS were male gender, metastases in LN at diagnosis, no SLNB in patients without clinical nodal metastases, and no perioperative radiotherapy. The estimated median overall survival (OS) was 6.9 years (95% CI 4.64-9.15). The negative independent risk factors for OS were male gender, age above 70, metastases in LN at diagnosis, and no SLNB in patients without clinical nodal metastases. Our results confirm that the MCC treatment should be conducted in an experienced multidisciplinary team; however, the outcomes are still unsatisfactory.

Efficacy of immunotherapy beyond RECIST progression in advanced melanoma: a real-world evidence.

Immunotherapy (ITH) holds the possibility of tumor burden decrease after initial RECIST 1.1 defined progression. The clinical concept of treating selected patients (pts) beyond disease progression (PD) is supported by so-called pseudoprogression phenomenon. The aim of this study was to evaluate real-life practice and outcomes related to treatment beyond (RECIST) progression (TBP) in advanced melanoma patients. Of 584 subsequent melanoma pts analyzed 77 (13.2%) received TBP. In this cohort, the median time to first PD (TTFP) was 5.29 months (m), while time to second PD (TTSP)-8.02 m. On TBP 23.4% pts achieved an objective response (OR), and next 42.9%-stabilization of the disease (SD). 1st PD was reported most often as the development of a new lesion or increase (> 20%) of the diameter of three or more targets. In about 50% second PD was observed as an increase in the diameter of different targets that in 1st PD. Multimodal treatment resulted in 9.82 m TTSP, while ITH alone-4.93 m (p = 0.128). An oligoprogressive pattern of first PD was associated with longer TTSP (HR 0.55, 95% CI: 0.32-0.94). Median OS after first PD was 28.75 months and correlated with OR during TBP (HR 0.18, 95% CI: 0.004-0.76). Selected clinically fit melanoma patients, despite evidence of first radiographic progression, may benefit from continued treatment with PD-1 checkpoint inhibitors, but the findings should be validated in larger prospective trials. Multidisciplinary treatment should be offered to advanced melanoma patients, including radiosurgery or stereotactic radiotherapy of single loci progressing during immunotherapy.

Long-term efficacy update of crizotinib in patients with advanced, inoperable inflammatory myofibroblastic tumour from EORTC trial 90101 CREATE.

PURPOSE: European Organisation for Research and Treatment of Cancer (EORTC) 90101 (CREATE) was a prospective, multicentric, non-randomised, open-label phase II basket trial to assess the efficacy and safety of crizotinib in patients with different types of cancers, including advanced inflammatory myofibroblastic tumour (IMT) with or without anaplastic lymphoma kinase (ALK) rearrangements. Here, we report updated results with long-term follow-up. PATIENTS/METHODS: After central reference pathology, eligible ALK-positive and ALK-negative patients with advanced/metastatic IMT deemed incurable with surgery, radiotherapy or systemic therapy received oral crizotinib 250 mg twice daily. The ALK status was assessed centrally using immunohistochemistry and fluorescence in situ hybridisation. The primary end-point was the proportion of patients who achieved an objective response (i.e. complete or partial response). If ≥6 ALK-positive patients achieved a confirmed response, the trial would be deemed successful. RESULTS: At data cut-off on 28th January 2021, we performed the final analysis of this trial. Of the 20 eligible and treated patients (19 of whom were evaluable for efficacy), with a median follow-up of 50 months, five were still on crizotinib treatment (4/12 ALK-positive and 1/8 ALK-negative patients). The updated objective response rate (ORR) was 66.7% (95% confidence interval [CI] 34.9-90.1%) in ALK-positive patients and 14.3% (95% CI 0.0-57.9%) in ALK-negative patients. In the ALK-positive and ALK-negative patients, the median progression-free survival was 18.0 months (95% CI 4.0-NE) and 14.3 months (95% CI 1.2-31.1), respectively; 3-year overall survival rates were 83.3% (95% CI 48.2-95.6) and 34.3% (95% CI 4.8-68.5). Safety results were consistent with previously reported data. CONCLUSION: These updated results confirm previous findings that crizotinib is effective, with durable responses, in patients with locally advanced or metastatic ALK-positive IMT. With further follow-up after the original primary analysis, the ORR increased, as patients derived long-term benefit and some responses converted from stable disease to partial responses. CLINICAL TRIAL NUMBER: EORTC 90101, NCT01524926.

Age as a Prognostic Factor in Patients with Ewing Sarcoma-The Polish Sarcoma Group Experience.

Ewing sarcoma (ES) is a rare and aggressive disease that requires multidisciplinary treatment with the use of chemotherapy, radiotherapy, and surgery. Our retrospective study aimed to analyze the prognostic factors and treatment results in different age groups of patients. Between 1998 and 2018, 569 patients with ES were treated in two referral centers. The patients were divided into four age groups (≤10 years; 11-18 years; 19-25, and >25). The treatment results and prognostic factors were assessed for each group. For statistical analyses, we used the Chi2 test, the Kaplan-Meier estimator with a log-rank test, and the multivariate Cox model. Five-year overall survival (OS) rate was 56%. In the age subgroups: ≤10 years, 11-18 years, 19-25 years, and >25 years, the 5-year OS rates were 75%, 58%, 41%, and 52%, respectively. Favorable prognostic factors: female gender (p = 0.024), non-axial localization (p = 0.005), VIDE regimen (p < 0.001), and surgery as a local treatment (p < 0.001) dominated in the group ≤10 years. In multivariate analysis, male (HR = 1.53), axial localization (HR = 1.46), M1 status at presentation (HR = 2.64), and age > 10 years (HR = 2.29) were associated with shorter OS. The treatment results in ES are significantly better in children aged ≤10 years; the challenge is to provide therapy for adolescents and young adults. The diagnostics and treatment of ES patients must be provided in referral centers.

Efficacy of Sirolimus Treatment in PEComa-10 Years of Practice Perspective.

Perivascular epithelioid cell tumors (PEComa) represent a family of rare mesenchymal tumors resultant from deregulation in mTOR pathway activity. The aim of this study is to evaluate the long-term efficacy of targeted PEComa treatment. We reviewed all consecutive patients with PEComa who started systemic treatment with sirolimus in our reference sarcoma center between January 2011 and August 2020. Histopathology of PEComa was reviewed and confirmed in all cases by a designated sarcoma pathologist. Any surviving progression-free patients were censored at the last follow-up (31 March 2021). Survival curves were calculated according to Kaplan-Meier method and compared with the log-rank test or a Cox proportional hazard model. Fifteen (12 females and 3 males) consecutive PEComa patients were treated. The median age of patients treated systemically was 50 years. Median progression-free survival (PFS) was 4.9 months (95% CI: 3.8-NA) for first-line chemotherapy and was not reached (95% CI: 42.0-NA) for sirolimus as first-line therapy. There was one objective response (OR) in the chemotherapy group. The OR rate reached 73% (11/15 cases) for sirolimus regardless of the treatment line. All patients archived disease control. Three patients died due to disease progression after 55, 32, and 32 months since metastatic disease diagnosis. After a median follow-up of 55.7 (range: 3.2-220) months, the 5 yr OS was 65% (CI 95% 39-100). Our study is the largest single-institution report on PEComa systemic targeted therapy and fills the gap in the field of advanced PEComa care since the FDA/EMEA approval of sirolimus.

Efficacy and Safety of Hypofractionated Preoperative Radiotherapy for Primary Locally Advanced Soft Tissue Sarcomas of Limbs or Trunk Wall.

BACKGROUND: The use of adjuvant radiotherapy (RT) shows a significantly decreased incidence of local recurrence (LR) in soft tissue sarcomas (STS). This study aimed to assess the treatment scheme's effect in patients with primary STS treated at one institution. METHODS: In this phase 2 trial, 311 patients aged ≥18 years with primary, locally advanced STS of the extremity or trunk wall were assigned to multimodal therapy conducted at one institution. The preoperative RT scheme consisted of 5 Gy per fraction for a total dose of 25 Gy. Surgery was performed within 2-4 days from the last day of RT. The primary endpoint was LR-free survival (LRFS). Adverse events of the treatment were assessed. RESULTS: We included 311 patients with primary locally advanced STS. The median tumor size was 11 cm. In total, 258 patients (83%) had high-grade tumors. In 260 patients (83.6%), clear surgical margins (R0) were obtained. Ninety-six patients (30.8%) had at least one type of treatment adverse event. LR was observed in 13.8% patients. The 5-year overall survival was 63%. CONCLUSION: In this group, with a significant percentage of patients with extensive, high-grade STS, hypofractionated preoperative RT was associated with good local control and tolerance.

Feasibility and Long-Term Efficacy of PEComa Treatment-20 Years of Experience.

Perivascular epithelioid cell tumors (PEComas) represent a family of rare mesenchymal neoplasms, some of which are malignant. There are no specific management guidelines for PEComas, and factors correlating with the disease course are not well defined. This analysis aimed to describe the outcomes of PEComa patients treated radically, including those treated exclusively in the national reference sarcoma center. The secondary aim of the study was to analyze factors associated with PEComa treatment efficacy. We performed an analysis of 27 patients subsequently treated radically for PEComa between 1999 and 2019 who were in follow-up in the national sarcoma reference center. The proportional-hazards model was used to compare the risk of death. The median age at diagnosis was 45 (21-67) years, and 67% of patients were female. The median follow-up period was 68 months (95% CI: 39-101). At the time of analysis, eleven patients (40.7%) experienced progression of the disease and four (14.8%) died. Surgery in the reference sarcoma center was associated with a longer disease control (log-rank p < 0.001). The 5-year-OS rate was 88% (95% CI: 74-100) for the whole analyzed group. We concluded that PEComa treatment should be managed in reference sarcoma centers by a multidisciplinary tumor board with an experienced surgical team. Microscopically radical resection is associated with a longer disease-free survival. Patients requiring long-term follow-ups as late recurrence may be expected.

What is the best front-line approach in patients with desmoid fibromatosis? - A retrospective analysis from a reference center.

INTRODUCTION: Desmoid fibromatosis (DF) is a locally aggressive, not metastasizing tumor associated with high local recurrence rates. Surgery was a standard-of-care for DF treatment; however, recently, conservative treatment and active surveillance are preferred. This study aimed to evaluate the real-life outcomes of DF treatment. MATERIALS AND METHODS: All consecutive patients diagnosed with DF and treated between 01.1999 and 12.2018 at one sarcoma reference institution were included in this retrospective analysis. Kaplan-Meier estimator, long-rank test, Cox regression model, and Chi2 tests were used for statistical analyses. RESULTS: The analyses included 363 patients (254 female, 109 male). 195 patients (53.7%) underwent surgical resection, and 139 (38.3%) experienced a watch-and-wait approach with or without concomitant therapy with nonsteroid anti-inflammatory drugs (NSAIDs) in the first line. Disease recurrence/progression occurred in 43.2% of patients treated with surgery and 42.6% in the watch-and-wait group, resulting in 5-year event-free survival (EFS) rates of 60% and 55%, respectively. There was no difference in EFS between both groups (HR1.28, 95%CI 0.91-1.79). Surgery without prior biopsy and extra-abdominal wall location was associated with inferior outcomes. CONCLUSIONS: Results of DF treatment in our center showed that watch-and-wait approach ± NSAIDs has similar efficacy to upfront surgery and allows to avoid unnecessary surgery in approximately half of the patients, primarily when tumors are located in unfavorable sites, like extremities.

The analysis of 3-year adjuvant therapy with imatinib in patients with high-risk molecular profiled gastrointestinal stromal tumors (GIST) treated in routine practice.

INTRODUCTION: The real-world data on adjuvant imatinib therapy in high-risk primary GIST are scarce. METHODS: We have analysed the data of 107 consecutive patients with gastrointestinal stromal tumour (GIST) after resection treated with adjuvant imatinib (for planned 3 years with initial dose 400 mg daily, started not later than 4 months after operation) in 6 oncological centres in 2013-2018. All patients were required to have high risk of recurrence (at least 50% according to NCCN/AFIP criteria), known mutational status to exclude PDGFRA D842V mutants and KIT/PDGFRA-wild type cases from therapy without any further selection. Median follow-up time was 27 months. RESULTS: The most common primary localization of GIST was small bowel (63 patients; 59%), followed by the stomach (40 patients; 37%). The majority of GIST cases harboured exon 11 KIT mutations (88 cases, 82%), 11 cases had exon 9 KIT mutations (10%), 8 had other KIT/PDGFRA mutations potentially sensitive to imatinib. Forty patients (37%) finished 3-year adjuvant imatinib therapy as planned, 48 (45%) still continue therapy, 5 (4.5%) patients had finished adjuvant therapy prematurely due to toxicity, 6 (6%) due to disease progression on treatment and 8 (7.5%) due to other reasons. The disease relapse was detected in 19 patients, of them in 5 cases in exon 9 KIT mutants (45%), and 14 cases in patients with exon 11 KIT mutations (11%) [p < 0.01]. Estimated 4-year relapse-free survival (RFS) rate is 78%. CONCLUSIONS: The early results of adjuvant therapy with imatinib in routine practice outside clinical trials in high-risk mutation-driven GIST patients only confirm high efficacy of this therapy with better tolerability than in clinical trials. We found overrepresentation of exon 9 KIT mutants and ruptured tumors in a group of patients with disease relapse.

Efficacy of Neoadjuvant Targeted Therapy for Borderline Resectable III B-D or IV Stage BRAF V600 Mutation-Positive Melanoma.

Neoadjuvant therapy for locally advanced disease or potentially resectable metastatic melanoma is expected to improve operability and clinical outcomes over upfront surgery and adjuvant treatment as it is for sarcoma, breast, rectal, esophageal, or gastric cancers. Patients with locoregional recurrence after initial surgery and those with advanced regional lymphatic metastases are at a high risk of relapse and melanoma-related death. There is an unmet clinical need to improve the outcomes for such patients. Patients with resectable bulky stage III or resectable stage IV histologically confirmed melanoma were enrolled and received standard-dose BRAFi/MEKi for at least 12 weeks before feasible resection of the pre-therapy target and then received at least for the next 40 weeks further BRAFi/MEKi. Of these patients, 37 were treated with dabrafenib and trametinib, three were treated with vemurafenib and cobimetinib, five with vemurafenib, and one with dabrafenib alone. All patients underwent surgery with 78% microscopically margin-negative resection (R0) resection. Ten patients achieved a complete pathological response. In patients with a major pathological response with no, or less than 10%, viable cells in the tumor, median disease free survival and progression free survival were significantly longer than in patients with a minor pathological response. No patient discontinued neoadjuvant BRAFi/MEKi due to toxicity. BRAFi/MEKi pre-treatment did not result in any new specific complications of surgery. Fourteen patients experienced disease recurrence or progression during post-operative treatment. We confirmed that BRAFi/MEKi combination is an effective and safe regimen in the perioperative treatment of melanoma. Pathological response to neoadjuvant treatment may be considered as a surrogate biomarker of disease recurrence.

Systemic Treatment for Advanced and Metastatic Malignant Peripheral Nerve Sheath Tumors-A Sarcoma Reference Center Experience.

Malignant peripheral nerve sheath tumor (MPNST) is a rare type of soft tissue sarcomas. The localized disease is usually treated with surgery along with perioperative chemo- or radiotherapy. However, up to 70% of patients can develop distant metastases. The study aimed to evaluate the modes and outcomes of systemic treatment of patients with diagnosed MPNST treated in a reference center. In total, 115 patients (56 female and 59 male) diagnosed with MPNST and treated due to unresectable or metastatic disease during 2000-2019 were included in the retrospective analysis. Schemes of systemic therapy and the outcomes-progression-free survival (PFS) and overall survival (OS)-were evaluated. The median PFS in the first line was 3.9 months (95% CI 2.5-5.4). Doxorubicin-based regimens were the most commonly used in the first line (50.4% of patients). There were no significant differences in PFS between chemotherapy regimens most commonly used in the first line (p = 0.111). The median OS was 15.0 months (95% CI 11.0-19.0) and the one-year OS rate was 63%. MPNST are resistant to the majority of systemic therapies, resulting in poor survival in advanced settings. Chemotherapy with doxorubicin and ifosfamide is associated with the best response and longest PFS. Future studies and the development of novel treatment options are necessary for the improvement of treatment outcomes.