Hypofractionated Radiotherapy in Locally Advanced Myxoid Liposarcomas of Extremities or Trunk Wall: Results of a Single-Arm Prospective Clinical Trial

Abstract

Introduction: Myxoid liposarcoma (MLPS) has been reported to be more radiosensitive compared with other soft tissue sarcomas. The main objective of the study was to assess the efficacy of hypofractionated radiotherapy (RT) in the preoperative setting in patients with locally advanced primary MLPS. Methods: Single-arm prospective exploratory clinical trial enrolled MLPS patients for preoperative 5 × 5 Gy RT with delayed surgery. The endpoints of the study were the rate of early wound healing complications and 5-year local control rate. Results: 29 patients (pts) were included, all had tumors located on the lower limb. The median maximum size of the tumor was 13 cm (IQR 10–15 cm). Early RT tolerance was good. Postoperative wound complications occurred in 11 pts (37.9%), late complications concerned 13.8% of patients. A total of 27 patients were included for the efficacy analyses. The pathological features of response to RT were detected in all analyzed surgical specimens. In 25 patients R0 margins were achieved, two patients had an R1 resection. None of the patients had local recurrence. Conclusion: Preoperative hypofractionated RT with a prolonged gap between RT and surgery is a feasible method of the management of MLPS, providing a good local control and low rates of treatment toxicity.

Radiation Therapy in Adult Soft Tissue Sarcoma—Current Knowledge and Future Directions: A Review and Expert Opinion

“…Moreover, the Polish group reported a subgroup analysis of their hypofractionation study focusing on 32 patients with myxoid liposarcoma (a histological subtype with known increased radiation sensitivity) and observed 5-year LRFS and OS rates of 90% and 68% [118]. Based on these results and the findings of early radiation induced tissue changes in the histological specimens despite the short interval to surgery, they conducted a phase II trials specifically investigating short-course RT in myxoid liposarcomas followed by delayed surgery [119]. They recently published their first results, indicating low acute and late toxicity and excellent local control (100% after a median f/u of 27 months).…”

The Feasibility Study of Hypofractionated Radiotherapy with Regional Hyperthermia in Soft Tissue Sarcomas

“…Therefore, a higher dose per fraction may enable better tumor control with lower total equivalent dose in 2-Gy fractions (EQD2) and the similar toxicity profile [ 16 ]. This hypothesis was validated in several early-phase clinical trials with hypofractionation for STS [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Unfortunately, chemoresistance is frequently associated with radioresistance; thus, hypofractionated RT alone may not provide satisfactory local control [ 25 , 26 ].…”

Current advances in radiotherapy for soft tissue sarcomas

“…Hypofractionated RT for STS was investigated in many prospective phase I or phase II clinical trials and prospective registries (tab. II); however there is no evidence from phase III trials to support its use in routine clinical practice [9][10][11][12][13][14][15]. Nevertheless, it may be used individually in selected patients upon the decision of the MTB.…”

“…Some STS subtypes are considered to be especially radiosensitive compared with other STS. In a prospective phase II single arm clinical trial conducted by the Polish Sarcoma Group, patients with locally advanced myxoid liposarcomas received one-week RT (25 Gy in five fractions) followed by a 6-8 weeks gap before surgery [12]. 29 patients were enrolled on the trial.…”