Vienna, Austria

ESTRO 2023

Session Item

Monday
May 15
16:00 - 17:00
Stolz 1
Sarcoma - Haematology
Falk Röder, Austria;
Karin Dieckmann, Austria
Mini-Oral
Clinical
16:00 - 17:00
Lessons learned from RT toxicity outcomes from UK VorteX and IMRiS trials for limb sarcoma
Rita Simoes, United Kingdom
MO-0947

Abstract

Lessons learned from RT toxicity outcomes from UK VorteX and IMRiS trials for limb sarcoma
Authors:

Rita Simoes1, Hakim-Moulay Dehbi2, Sarah Gulliford3, Beatrice Seddon4, Martin Robinson5, Peter Hoskin6, Sharon Forsyth7, Laura White8, Piers Gaunt9, Ana Hughes9, Elizabeth Miles10, Kevin Harrington11, Aisha Miah12

1The Institute of Cancer Research; The Royal Marsden Hospital; University College London Hospitals; RTTQA group, Radiotherapy, London, United Kingdom; 2Comprehensive Clinical Trials Unit at University College London, Inst of Clinical Trials & Methodology, London, United Kingdom; 3University College London Hospital NHS Foundation Trust, Radiotherapy Physics, London, United Kingdom; 4University College London Hospital NHS Foundation Trust, Sarcoma Unit, London, United Kingdom; 5University of Sheffield, Department of Oncology, Sheffield, United Kingdom; 6University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom; 7Cancer Research UK & UCL Cancer Trials Centre, UCL Cancer Trials Centre, London, United Kingdom; 8Cancer Research UK & UCL Cancer Trials Centre, Cancer Trials Centre, London, United Kingdom; 9Cancer Research UK Clinical Trials Unit, Clinical Trials Unit, Birmingham, United Kingdom; 10National Radiotherapy Trials Quality Assurance Group (RTTQA), Mount Vernon Hospital, Northwood, United Kingdom; 11The institute of Cancer Research, Radiotherapy and Imaging, London, United Kingdom; 12The Royal Marsden Hospital, Sarcoma Unit, London, United Kingdom

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Purpose or Objective

The VorteX (NCT00423618) phase III trial studied whether a reduction in radiotherapy treatment volumes reduced normal tissue toxicity for soft tissue sarcoma of the extremities (STSE) treated with adjuvant radiotherapy to 66 Gy. The IMRiS (NCT02520128) phase II trial studied the feasibility of Intensity-Modulated Radiotherapy (IMRT) in the neo-adjuvant (50 Gy) and adjuvant (60 Gy) settings. This work compares toxicities reported for both trials.

Material and Methods

Descriptive statistics were calculated for maximum RTOG and Stern scale toxicities occurring from 6 to 24 months for skin dermatitis, subcutaneous tissue fibrosis, bone fractures, joint stiffness and lymphoedema. Toxicities were reported by trial, radiotherapy technique (3D-conformal radiotherapy (3DCRT) and IMRT) and radiotherapy regimen (adjuvant and neo-adjuvant) and compared using the Chi2 test.

Results

Toxicity data from 354 patients were available (193 VorteX; 161 IMRiS). Maximum toxicities from 6 to 24 months are shown in table 1. Adjuvant RT was given to 248 (70%) patients and 3DCRT was given to 180 (50.8%) patients. Skin dermatitis, subcutaneous tissue fibrosis, and bone fractures grade 2 or above (grade2+) toxicities were higher in VorteX trial, except for joint stiffness which was higher in IMRiS. Table 2 shows the comparison of toxicities. Grade2+ toxicities were significantly higher in VorteX (p-value<0.01), 3DCRT and adjuvant & 3DCRT (p-value<0.01). Grade 2+ toxicities in the adjuvant and neo-adjuvant RT groups were not significantly different (p=0.07).

Conclusion

Grade 2+ toxicity incidence was higher in VORTEX than IMRiS patients, most likely due to patients being treated with adjuvant 3DCRT and to higher radiotherapy doses of 66Gy.  Toxicities were significantly higher for 3DCRT than IMRT, the use of 3DCRT cannot be disregarded as this comparison was not done as part of a clinical trial. Both clinical trials provide valuable clinical and dosimetric data from which to develop dose-volume constraints for normal tissue toxicities and to predict for frequency and degree of toxicities for STSE. This work is currently being undertaken.

The first author is clinical doctoral research fellow CDR-2018-04-ST2-004, funded by HEE/ NIHR.