Effect of radiotherapy on local recurrence, distant metastasis and overall survival in 1200 extremity soft tissue sarcoma patients. Retrospective analysis using IPTW-adjusted models

• Published in: Radiotherapy and oncology 2023-12, Vol.189, p.109944-109944, Article 109944
• Main Authors: Smolle, Maria A., Andreou, Dimosthenis, Wölfel, Judith, Acem, Ibtissam, Aj Van De Sande, Michiel, Jeys, Lee, Bonenkamp, Han, Pollock, Rob, Tunn, Per-Ulf, Haas, Rick, Posch, Florian, Van Ginkel, Robert J., Verhoef, Cornelis, Liegl-Atzwanger, Bernadette, Moustafa-Hubmer, Dalia, Jost, Philipp J., Leithner, Andreas, Szkandera, Joanna
• Format: Article
• Language: English
• Subjects: Adjuvant radiotherapy; Distant Metastasis; Local recurrence; Neoadjuvant radiotherapy; Overall survival; Soft Tissue Sarcoma
• ISSN: 0167-8140; 1879-0887
• DOI: 10.1016/j.radonc.2023.109944

•In comparison to no radiotherapy (RTX), administration of neoadjuvant radiotherapy (NRTX) reduces local recurrence (LR) risk in extremity soft tissue sarcoma (eSTS)•Adjuvant radiotherapy (ARTX) reduces LR risk as compared with no RTX.•No association of RTX – regardless of timing – with regards to distant metastasis (DM) risk or overall survival (OS) is present when compared to no RTX.•No significant difference between NRTX and ARTX regarding DM risk or OS can be found.•NRTX appears to reduce LR risk to a greater extent than ARTX. Neoadjuvant (NRTX) and adjuvant radiotherapy (ARTX) reduce local recurrence (LR) risk in extremity soft tissue sarcoma (eSTS), yet their impact on distant metastasis (DM) and overall survival (OS) is less well defined. This study aimed at analysing the influence of NRTX/ARTX on all three endpoints using a retrospective, multicentre eSTS cohort. 1200 patients (mean age: 60.7 ± 16.8 years; 44.4 % females) were retrospectively included, treated with limb sparing surgery and curative intent for localised, high grade (G2/3) eSTS. 194 (16.2 %), 790 (65.8 %), and 216 (18.0 %) patients had received NRTX, ARTX and no RTX, respectively. For the resulting three groups (no RTX vs. NRTX, no RTX vs. ARTX, NRTX vs. ARTX) Fine&Gray models for LR and DM, and Cox-regression models for OS were calculated, with IPTW-modelling adjusting for imbalances between groups. In the IPTW-adjusted analysis, NRTX was associated with lower LR-risk in comparison to no RTX (SHR [subhazard ratio]: 0.236; p = 0.003), whilst no impact on DM-risk (p = 0.576) or OS (p = 1.000) was found. IPTW-weighted analysis for no RTX vs. ARTX revealed a significant positive association between ARTX and lower LR-risk (SHR: 0.479, p = 0.003), but again no impact on DM-risk (p = 0.363) or OS (p = 0.534). IPTW-weighted model for NRTX vs. ARTX showed significantly lower LR-risk for NRTX (SHR for ARTX: 3.433; p = 0.003) but no difference regarding DM-risk (p = 1.000) or OS (p = 0.639). NRTX and ARTX are associated with lower LR-risk, but do not seem to affect DM-risk or OS. NRTX may be favoured over ARTX as our results indicate better local control rates.