Compared to other sarcomas, myxoid liposarcoma (MLS) is exceptionally sensitive to radiation therapy, but the underlying mechanism remains unknown. The objective was to assess the tissue-based... Show moreCompared to other sarcomas, myxoid liposarcoma (MLS) is exceptionally sensitive to radiation therapy, but the underlying mechanism remains unknown. The objective was to assess the tissue-based changes in MLS during and after neoadjuvant radiotherapy in 26 patients of the DOREMY trial. Morphological assessment was performed on biopsies pre-treatment, after 8 fractions, 16 factions, and after surgical resection and included percentage of viable tumor cells, hyalinization, necrosis, and fatty maturation. Furthermore, immunohistochemistry was performed for apoptosis (cleaved caspase-3), anti-apoptosis (Bcl-2), activity of mTOR signaling (phospho-S6), hypoxia (CAIX), proliferation (Ki67), inflammation (CD45 and CD68), and microvessel density (CD34 Chalkley count). A pronounced reduction in vital tumor cells was observed early with a drop to 32.5% (median) tumor cells (IQR 10–93.8%) after 8 fractions. This decreased further to 10% (IQR 5–30%) after 16 fractions and 7.5% (IQR 5–15%) in the surgical specimen. All but one patient had an excellent response with < 50% remaining tumor cells. Inversely, treatment response was mainly observed as hyalinization and less often as fatty maturation. Additionally, a decrease of inflammatory cells was noticed especially during the first eight fractions. Microvessel density remained stable over time. Immunohistochemical markers for apoptosis, anti-apoptosis, activity of mTOR signaling, proliferation, and hypoxia did not show any marked changes within the remaining tumor cells during and after radiotherapy. As a modest dose of neoadjuvant radiotherapy induces profound tissue changes in MLS, mainly during the first 8 fractions, current findings might suggest that in a carefully selected patient population further deintensification of radiotherapy might be explored. Show less
Background: Histotype specific neoadjuvant therapy response data is scarce in soft tissue sarcomas. This study aimed to assess the impact of a moderate radiotherapy (RT) dose on resectability and... Show moreBackground: Histotype specific neoadjuvant therapy response data is scarce in soft tissue sarcomas. This study aimed to assess the impact of a moderate radiotherapy (RT) dose on resectability and to correlate MRI parameters to pathological treatment response in Myxoid Liposarcoma (MLS).Methods: This prospective, multicenter, single-arm, phase 2 trial assessed the radiological effects of 36 Gy of preoperative radiotherapy in primary non-metastatic MLS (n=34). Distance of the tumor to the neurovascular bundle, tumor dimensions, fat fraction, enhancing fraction were determined on MRI scans at baseline, after 8 and 16 fractions, and preoperatively. Pathological response was established by central pathology review.Results: Preoperative radiotherapy resulted in a median increase of 2 mm (IQR 0 to 6) of the distance of the tumor to the neurovascular bundle. As compared to baseline, the median change of the tumor volume, craniocaudal diameter and axial diameter at preoperative MRI were -60% (IQR -74 to -41), -19% (IQR -23 to -7) and -20% (IQR -29 to -12), respectively. The median fat fraction of 0.1 (IQR 0.0-0.1) and enhancing fraction of 0.8 (IQR 0.6 to 0.9) at baseline, changed to 0.2 (IQR 0.1 to 0.5) and to 0.5(IQR 0.4 to 0.9) preoperatively, respectively. Radiological signs of response in terms of volume, enhancing fraction and fat fraction were correlated with specific pathological signs of response like hyalinization, necrosis and fatty maturation.Conclusions: A moderate dose of preoperative radiotherapy may improve resectability in MLS and could facilitate achievement of clear margins and function preservation. MRI features which were predictive for expressions of pathological response, can play a role in further personalization of neoadjuvant treatment strategies in order to improve outcome in MLS. (C) 2021 Elsevier Ltd, BASO - The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved. Show less
Lansu, J.; Houdt, W.J. van; Langevelde, K. van; Ende, P.L.A. van den; Graaf, W.T.A. van der; Schrage, Y.; ... ; Haas, R.L. 2021
Introduction: Oligometastatic disease and/or oligoprogression in myxoid liposarcoma(oMLS) triggers discussions on local treatment options and delay of systemic treatments. We hypothesized that... Show moreIntroduction: Oligometastatic disease and/or oligoprogression in myxoid liposarcoma(oMLS) triggers discussions on local treatment options and delay of systemic treatments. We hypothesized that satisfactory local control and postponement of systemic therapy could be achieved with a modest radiotherapy(RT) dose in oMLS.Methods: The DOREMY trial is a multicenter, phase 2 trial evaluating efficacy and toxicity of a modest RT dose in both localized and oMLS; this report presents the data of the oMLS cohort treated with 36 Gy in 12-18 fractions with optional subsequent metastasectomy. The primary endpoint was local progression free survival(LPFS). Secondary endpoints included postponement of systemic therapy, symptom reduction, radiological objective response, and toxicity.Results: Nine patients with a total of 25 lesions were included, with a median follow-up of 23 months. The median number of lesions per patient was three and the trunk wall and bone were the most frequently affected sites. In lesions treated with definitive RT(n = 21), LPFS rates at 1, 2, and 3 years were respectively 73%, 61%, and 40%. Radiological objective response and clinical symptom reduction were achieved in 8/15(53%) and 9/10(90%) of the evaluable lesions, respectively. No local recurrences occurred in lesions treated with RT and metastasectomy(n = 4). For the entire study population, the median postponement of systemic therapy was 10 months. Grade >= 2 toxicity was observed in 2/9(22%) of patients.Conclusions: This trial suggests that 36 Gy could possibly be effective to achieve local control, postpone systemic therapy and reduce symptoms in oMLS. Given the minimal toxicity this treatment could be reasonably considered in oMLS.(c) 2021 Elsevier B.V. All rights reserved. Radiotherapy and Oncology 158 (2021) 33-39 Show less
The work presented in this thesis describes the improvement and application of on-tissue chemistry for in-situ biomolecular analysis using matrix assisted-laser desorption/ionization mass... Show moreThe work presented in this thesis describes the improvement and application of on-tissue chemistry for in-situ biomolecular analysis using matrix assisted-laser desorption/ionization mass spectrometry imaging (MALDI-MSI). We have proposed new methodologies, applying on-tissue (enzymatic) chemistry, to increase the molecular information obtained in a MALDI-MSI analysis. We have also developed an automated histology-guided MSI platform, based on state-of-the-art image processing tools, to facilitate high mass and spatial resolution MALDI-MSI while maintaining reasonable data loads and acquisition times. We have shown the importance of these methods in a clinical biomarker discovery study on myxoid liposarcoma tissues. Show less
The aim of this thesis is to gain more insight in the molecular pathology of soft tissue sarcomas, especially leiomyosarcoma and myxoid liposarcoma. The group of soft tissue sarcomas... Show moreThe aim of this thesis is to gain more insight in the molecular pathology of soft tissue sarcomas, especially leiomyosarcoma and myxoid liposarcoma. The group of soft tissue sarcomas constitute a large number of different, mostly rare, neoplasms, each with their own histopathology, genetic profile and clinical features. Here we focus on the molecular profile of these two soft tissue tumours and performed studies to identify potential targets for specific therapeutic strategies. Leiomyosarcomas are characterized by a complex genetic profile which makes it difficult to identify targets for treatment. We here show that MED12 mutations are restricted to uterine smooth muscle tumours, and describe the occurrence of non-recurrent translocations in two cases of soft tissue leiomyosarcomas. Next, we show high expression of the Bcl family members in leiomyosarcomas, and using cell lines we could demonstrate that these proteins play a role in chemoresistance. Myxoid liposarcomas have a well-defined recurrent translocation. We show expression of the cancer-testis antigen NY-ESO-1 in a large proportion of tumours, providing options for immunotherapy. We present a novel, spontaneously immortalized myxoid liposarcoma cell line which was used for a largescale drug screen, resulting in the identification of a promising novel target. Show less
