ESTRO 2024 Congress report

The radiation therapists’ (RTT) debate on abdominal compression took place on the final morning of the congress. A large audience attended, which highlighted the level of interest in this hot topic. Two speakers educated and entertained as they set out their positions on the pros and cons of abdominal compression as a means of motion management in the current landscape of advanced image-guided radiation therapy, artificial intelligence (AI) and personalised radiotherapy.

A starting poll showed 52% for and 48% against the motion.

First, Emma White set out her three main arguments for the motion.

Emma argued convincingly that as a motion management strategy, abdominal compression was not suitable for all patients. She quoted Cihoric et al., who reported exclusion criteria of patients with prior surgery, pain and high body-mass indices.

She suggested that other techniques such as breath hold or gating had dosimetric benefits and were transferable to a wider range of sites. This argument was focused on the fact that abdominal compression resulted in an internal target volume approach with the entire tumour motion encompassed in the target volume, whereas breath hold or gating spared more normal tissue and was aimed to reduce toxicities for the patient.

Finally, with the advent of AI, Emma stated that tumour tracking with less intervention for the patient was a more desirable solution. She highlighted work by Zhang et al. and Li et al., who had demonstrated that we could better establish an internal/ external motion correlation through the use of AI technology, so why would we settle for an uncomfortable compression belt with sub-optimal dosimetric outcomes?

Next, Michael Velec argued against the motion.

His first argument was focused on the large evidence base that supported the use of a compression belt; he highlighted the long history of its use in stereotactic radiotherapy. In particular, he noted work by Daly et al. in 2013 that demonstrated that abdominal compression was the most commonly used strategy with 51% of oncologists reporting that it was their chosen strategy.

Michael argued strongly that the fact that it was simple and patient compliance was not required was a distinct pro for abdominal compression. Work by Schneider, published in ctRO, was highlighted to support this argument, but Michael went a step further and added to the data with the revelation that he himself was wearing an abdominal compression belt whilst debating and had no comfort concerns!

Finally, Michael made the strong point that this was a cost-effective solution accessible to all, not just to higher income countries. It was an adaptable solution that could be used across all platforms as practice progressed seamlessly from Linac, to MR Linac and even to protons.

It may have been this last point that swung the vote in his favour, as the final voting revealed that 68% of the audience now were against the motion that abdominal compression was no longer a suitable motion management strategy, considering patient comfort and clinical benefit.

A key take-home message from both sides was the need to focus on the patient, as well as the relevant clinical factors, and to select an individualised and optimised motion management strategy for the treatment of moving targets.

Sarah Barrett

Assistant professor in radiation therapy
Trinity College Dublin , Ireland

ESTRO lung focus group