A moderate dose of preoperative radiotherapy may improve resectability in myxoid liposarcoma

• Published in: European journal of surgical oncology 2021-10, Vol.47 (10), p.2633-2639
• Main Authors: Lansu, Jules, Braam, Pètra M., van Werkhoven, Erik, Scholten, Astrid N., Schrage, Yvonne, van Houdt, Winan J., van Langevelde, Kirsten, Haas, Rick L.
• Format: Article
• Language: English
• Subjects: Adipose Tissue - diagnostic imaging; Adiposity; Adult; Blood Vessels - diagnostic imaging; Dose Fractionation, Radiation; Female; Humans; Liposarcoma, Myxoid - diagnostic imaging; Liposarcoma, Myxoid - pathology; Liposarcoma, Myxoid - radiotherapy; Liposarcoma, Myxoid - surgery; Magnetic Resonance Imaging; Male; Margins of Excision; Middle Aged; MRI; Myxoid liposarcoma; Myxoid liposarcomas; Neoadjuvant radiotherapy; Neoadjuvant Therapy; Neoplasm, Residual; Peripheral Nerves - diagnostic imaging; Preoperative Period; Prospective Studies; Radiotherapy, Adjuvant; Soft Tissue Neoplasms - diagnostic imaging; Soft Tissue Neoplasms - pathology; Soft Tissue Neoplasms - radiotherapy; Soft Tissue Neoplasms - surgery; Soft tissue sarcoma; Soft tissue sarcomas; Tumor Burden
• ISSN: 0748-7983; 1532-2157
• DOI: 10.1016/j.ejso.2021.06.020

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). 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. 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. 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. •Myxoid Liposarcomas (MLS) are exceptionally radiosensitive•A moderate dose of preoperative RT may improve resectability in MLS•The tumor to neurovascular bundle distance increases with 2 mm after 36Gy of RT•Volume, enhancing fraction and fat fraction on MRI may predict pathological response