ESTRO 2022 - Abstract Book

S161

Abstract book

ESTRO 2022

1 University Medical Center Groningen, Radiation Oncology, Groningen, The Netherlands

Abstract Text Over the recent years, awareness for lymphopenia as toxicity of radiotherapy is increased. Lymphopenia is reported in patients treated with chemoradiotherapy for several cancer types. In esophageal cancer the incidence of grade IV lymphopenia ranges from 11 to 40%. Grade IV lymphopenia is associated with worse overall survival and a lower incidence of pathologic complete response after treatment. The risk of lymphopenia is predicted by baseline absolute lymphocyte count, planning target volume (PTV), age, body mass index and radiotherapy technique (proton vs photon radiotherapy). Others report on associations between radiation dose to critical organs like heart, spleen, bone marrow, or the circulation blood pool and the development of lymphopenia. New radiotherapy techniques, that aim to reduce the dose to organs at risk, might consequently reduce the risk of lymphopenia. In the treatment of esophageal cancer, proton radiotherapy, with dose reductions to heart and lungs, reduces the risk of grade IV lymphopenia compared to photon radiotherapy (IMRT). In summary, lymphopenia is a frequently observed side effect of chemoradiotherapy in several tumour sites. Radiotherapy techniques that reduce the dose to critical organs, like proton radiotherapy, seem to reduce the risk of lymphopenia.

SP-0195 How can we use AI in daily practice to minimise the risk of developing lymphopenia when irradiating solid tumours?

D. Routman

USA Abstract not available

Symposium: Preserving brachytherapy skills for the future

SP-0196 Status of brachytherapy education for brachytherapists and future needs in Europe

A. Sturdza

Canada Abstract not available

SP-0197 Status of brachytherapy education for brachytherapists and future needs in North America

M. Kamrava

USA Abstract not available

SP-0198 Status of brachytherapy education for medical physicists and future needs

C. Kirisits 1

1 Medical University of Vienna, Dept. of Radiation Oncology, Vienna, Austria

Abstract Text Brachytherapy education for medical physicists is currently part of national, European (ESTRO-EFOMP), North American (e.g. AAPM) or Asian (e.g. India) core curricula for medical physics experts in radiotherapy. Although there are differences in the distribution of learning skills via internship or courses and the overall amount of training hours, brachytherapy education is an integral part of those regulations. An important issue is that in contrast to most external beam techniques, brachytherapy is not performed in every radiotherapy department. If performed there is a huge variation in centers regarding treatment approaches (from standard plans to image-based treatment planning) and treated sites (centers performing a huge variety of treatments versus centers focusing only on prostate or GYN). The trend towards centralization with less centers performing brachytherapy increases the problem of missing training sites. While in some countries the education of those residents working in centers without brachytherapy remains limited to courses, other countries support an internship for a limited time in other centers. Future needs have to be defined in a strategic way. The status quo might result in a limited basic education for all medical physics experts, where only those at selected centers will reach an expert level in brachytherapy. However, these special skills might not be visible in certificates. The other option would be therefore to even reduce brachytherapy skills from the current curricula, while expanding it for dedicated extra certification. In any case the needs also have to be defined according to the future requirements in brachytherapy. The basics of brachytherapy dosimetry and quality assurance are mandatory and have to be included with high priority. On the other hand, the required expertise for treatment planning is changing. There is an increasing focus on imaging (e.g. also special techniques as ultrasound and MRI) and image handling (registration and fusion of different modalities and for different time points). Treatment planning expertise has to include traditional forward planning approaches as well as inverse optimization and the correct definition of constraints (dose and volume, but also spatial dose and dose rate distribution). Training in automated planning and even more in QA for those techniques will become essential. Finally, brachytherapy is a highly interdisciplinary technique. Due to the close interaction of physicians, radiation technologists and medical physicists, often also together in an operating theater, brachytherapy physicists might need more insight into clinical issues – anatomy,