Although many technical studies have been published on the use of the Ethos system for online adaptive radiotherapy (oART), papers showing the clinical outcomes of actual patient treatments are appearing slowly, and larger prospective studies require time to accrue and for data to mature before being reported. Therefore, in April 2024 Varian Medical Affairs sponsored a publishing competition, in collaboration with Cureus.com, with the goal of increasing clinical information on oART.
A call for papers was issued asking for case reports of patients treated with oART guided by pre-session CT or CBCT scans. Adaptive treatment with the Ethos system met these criteria clearly, and so by the competition deadline in late July, nearly 40 cases were submitted, the vast majority by Ethos users, and several featuring advanced imaging with HyperSight.
Cases were submitted from at least 24 institutions, and covered over 13 distinct adaptive treatments. Some highlights of the cases submitted are listed below. They include complex treatments that would be difficult to treat without online adaptation and/or advanced imaging.
- Treatment of prostate cancer in a patient with bilateral full hip arthroplasty and inflammatory bowel disease (IBD), enabled by the metal artifact reduction capability of HyperSight
- Large oligometastatic ultra-central lung lesions treated with SBRT concurrent with immunotherapy
- Bilateral adrenal masses of large B-cell lymphoma during CAR-T cell therapy
- Re-irradiation with SBRT of radioresistant retroperitoneal sarcoma
A wide range of other cases involved difficult treatment sites throughout the body. In almost every case Ethos oART led to a reduction in normal tissue doses and/or a maintenance of treatment target coverage, and in some cases allowed reduction of margins below what is conventional.
At a time when more and more Ethos users are starting or expanding their adaptive RT programs, this large set of real-world clinical case reports will provide creative concepts and guidelines to facilitate safe online adaptive treatments.
Learn more about the competition and read the submitted papers on the Cureus Journal website.