S3017
Invited Speaker
ESTRO 2026
5363 The biology behind the beam: Biomarkers for smarter radiotherapy in gyn cancers Supriya Chopra Radiation Oncology, ACTREC,Tata Memorial Centre, Navi Mumbai, India. Radiation Oncology, Homi Bhabha National Institution, Mumbai, India Biomarkers for gynecological cancers: the biology behind the beams educational lecture will focus on the key biomarkers that affect the clinical decision process in gynecological cancers. In recent years international collaborative studies like BIOEMBRACE have reported the impact of biomarkers on local control and disease outcomes. The talk will discuss about p16 and PDL-1 biology and how it has potential to impact treatment decisions. Results from prospective clinical trials that deploy pathway inhibitors and biomarkers or investigate impact of radiation on immune milieu will be discussed alongside the important crucial role of circulating DNA for cervix cancer. While the impact of biomarkers in treatment selection is yet evolving for cervix cancer, there has been a huge leap in the integration of biomarkers for Endometrial Cancer Treatment selection. How the future of radiation and brachytherapy will be integrated with biomarkers for these 2 common cancers will be discussed.
demonstrating stable motion. Patients were characterised based on motion stability across fractions. A qualitative sub-study, using semi- structured interviews analysed through constructivist grounded theory, explored patient experiences of immobilisation. Results Analysis of SGRT data identified a subgroup of patients (30%) who consistently exhibited minimal intra- fraction motion throughout treatment, while others showed greater variability. Bayesian modelling suggests that patient-specific motion patterns may be predictable, supporting stratification for personalised margin selection. Dosimetric evaluation indicates that margin reduction (e.g. from 3 mm to 2 mm) in stable patients could meaningfully reduce organ-at-risk (OAR) dose, with 66% of stable patients demonstrating a potential dose reduction of 1.5 Gy. Qualitative findings highlighted immobilisation as a central component of the treatment experience. Patients reported challenges with mask tolerance and emphasised the importance of clear communication, understanding, and involvement in decision-making. Preferences regarding mask type varied, reflecting differing priorities around comfort, security, and anxiety. Discussion These findings support a move towards personalised radiotherapy, integrating quantitative motion data with patient-centred insights. SGRT offers a practical mechanism to identify patients suitable for margin reduction, while ongoing validation work at SLRON aims to confirm predictive modelling approaches. Additionally, immobilisation represents an opportunity for shared decision-making, where incorporating patient preferences may enhance engagement and treatment experience. Conclusion Personalised immobilisation strategies and adaptive margin selection are feasible and clinically relevant in head and neck radiotherapy. Combining SGRT-derived motion data with patient preference enables a shift from a “one-size-fits-all” approach towards individualised, evidence-informed care. References: Malone C, Ryan S, Nicholson J, O'Maolalai R, O'Donovan R, McArdle O, et al. Intrafraction motion stability of open vs. closed facemasks in head and neck radiotherapy: Insights from the OPEN phase III trial. Radiother Oncol. 2025 Aug;209:110941. doi:10.1016/j.radonc.2025.110941.
5367 One size doesn't fit all: Personalising immobilisation and margins in head & neck
radiation therapy Róisín Ó Maolalaí
Radiation Therapy, Clinical Trials Unit, St. Luke's Radiation Oncology Network, Dublin, Ireland
Background The OPEN Trial is the largest phase III randomised study comparing conventional closed masks with open-face masks for head and neck immobilisation. (1) Results demonstrated that open-face masks achieve comparable set-up and intra-fraction accuracy to closed masks, while significantly improving patient experience and reducing distress. However, inter- patient variability in intra-fraction motion raises questions regarding the appropriateness of uniform planning margins. Methods As part of the OPEN Trial, continuous surface-guided radiotherapy (SGRT) intra-fraction motion data from 105 patients were analysed. Bayesian modelling approaches, developed by SLRON research fellows, were applied to investigate the feasibility of predicting patient-specific intra-fraction motion and stratifying patients into margin groups. A dosimetric analysis evaluated the impact of reduced margins in patients
Made with FlippingBook - Share PDF online