Radiat Oncol J.  2025 Mar;43(1):6-12. 10.3857/roj.2024.00297.

Feasibility and safety study of ultra-hypofractionated neoadjuvant radiotherapy to margins-at-risk in retroperitoneal sarcoma

• Wong RX
• Yang VSW
• Chia CS
• Looi WS
• Nei WL
• Ong CAJ

• KMID: 2566119
• DOI: http://doi.org/10.3857/roj.2024.00297

Abstract

Purpose
Retroperitoneal sarcomas (RPS) are rare tumors that present unique challenges, often due to late presentation, and the proximity of critical organs makes complete surgical resection challenging. This study aimed to assess the feasibility of neoadjuvant short-course radiotherapy (SCRT) targeting margins-at-risk and to assess its potential impact on outcomes.
Materials and Methods
This is a single-center, prospective, non-randomized feasibility study. SCRT was administered via image-guided volumetric modulated arc therapy, consisting of 5 fractions of daily radiotherapy followed by immediate surgery. As a starting dose, patients were prescribed 25 Gy in 5 fractions. For the escalation stage, patients were prescribed 30 Gy in 5 fractions. Only the presumed threatened surgical margins were delineated for large tumors.
Results
Patients with either primary or recurrent RPS were recruited. Eight patients underwent SCRT but one patient did not have a resection as planned. Seven patients underwent surgical resection, of whom one passed away 3 months postoperative from a cardiac event. After a median follow-up of 20.5 months for the six postoperative survivors, there were no overt long-term toxicities and one patient relapsed out-of-radiotherapy-field.
Conclusion
SCRT to RPS with a margin boost followed by immediate surgery is worth investigating. A starting dose of 30 Gy in 5 fractions is recommended for further studies. Longer-term follow-up is necessary.

Keyword

Sarcoma; Radiotherapy; Neoadjuvant therapy; Hypo-fractionated radiotherapy; En bloc surgery