ESTRO 2024 - Abstract Book

S121 ESTRO 2024 In tongue cancers perioperative implantation is helpful along with limited resection for organ and function preservation. Dose escalation with BT is also useful in patients with margin positive disease. Techniques of implantation are either loop technique, non-looping loop or straight tube technique. In oropharyngeal cancers boost BT is useful for dose escalation in intermediate risk and high risk tumours. Boost BT is also useful for reduction of xerostomia and improving quality of life. In a randomized trial comparing IMRT alone with IMRT and BT, statistically significant improvement in the reduction of xerostomia was observed with the use of BT. BT utilization also showed a trend towards improved survival. Techniques for base of the tongue are non-looping loop technique or straight tube technique. Soft palate BT is performed using loop technique while 3 straight/curved tubes are inserted for tonsillar tumours. In nasopharyngeal cancer BT is considered for dose escalation for residual disease.BT boost may possibly result in improved quality of life for nasopharyngeal cancers. BT is done either as endocavitary BT or as interstitial BT which is done guided by endoscopy. In paranasal sinus tumours, BT is considered as a boost in addition to EBRT for dose escalation as well as to reduce the dose to the critical structures. Close cooperation with the surgical team is required for the intraoperative placement of catheters for PNS BT. Overall BT boost is a very useful tool for dose escalation as well as reducing the doses of OAR thereby achieving good local control rates, preserving organ and function in head neck cancers. Invited Speaker

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The role of proton radiotherapy in the treatment of oesophageal cancer

Christina Muijs

University Medical Center Groningen, Radiation Oncology, Groningen, Netherlands

Abstract:

Radiotherapy plays an essential role in the treatment of esophageal cancer, both in neo-adjuvant and in definitive setting. However, intra-thoracic radiotherapy is associated with complication risks, as both the heart and the lungs are located in close proximity of the esophageal cancer, and most patients need to undergo a surgical resection after chemoradiotherapy (CRT). However, as we approach 2025, patients increasingly request for organ preservation strategies. Proton radiotherapy (PRT), with its precision and tissue-sparing capabilities, emerges as a promising modality within this evolving landscape. Post-operative complication risks might be reduced by PRT as a consequences of lower heart and lung doses, as was demonstrated in the randomized controlled trial by Lin et al and several prospective cohort studies. Moreover, PRT has the potential to mitigate lymphopenia after CRT. Lymphocytes are essential for the immune response to CRT, and preservation of these lymphocytes might improve patients outcome as severe lymphopenia is associated with worse pathologic tumor response, disease free and overall survival. However, it is imperative to acknowledge that not all patients may equally benefit from PRT. Therefore, the model based approach is being used in the Netherlands to select patients that benefit most of PRT. It offers a systematic framework, based on prediction models that are being used to translate the dosimetric benefit into estimates of complication risk reductions, to identify the patients for whom PRT seems favorable.