3rd ESTRO Forum

av Iuliana Dasu, 24 - 28 april 2015

The 3rd ESTRO Forum had a very interesting scientific programme covering state of the art science and education in radiation oncology, radiation biology, radiation physics and technology.

There were many interesting presentations at the conference but I would like to particularly highlight the following ones which focused on the benefits but also potential challenges of hypo-fractionation:

– Risk assessment and clinical management by A.M. Van Mourik (Netherlands Cancer Institute Antoni van Leeuwenhoek, Hospital, Radiotherapy Department, Amsterdam, The Netherlands). Dr. Van Mourik discussed the geometric inaccuracies present throughout the treatment chain in radiosurgery or stereotactic radiotherapy, besides setup variability and intrafraction motion, including geometric imperfections in treatment preparation, planning and dose delivery become relevant in stereotactic treatment. The impact of those geometric inaccuracies depends on the type of error but also on the technological treatment characteristics. Quoting from Dr. Van Mourik’s abstract, current perspectives on the management of these geometric uncertainties range between two extremes: the radiosurgery perspective (single fraction, ablative dose, no margins) and the radiotherapy perspective (hypo-fractionated, high dose, PTV/PRV margin). Various combinations of and adaptations on these perspectives are described in the literature. Additional considerations that influence the management of geometric uncertainties include: disease site, tumor type, treatment intent, treatment risk, radiobiology, clinical experience etc. In practice, the ways in which geometric uncertainties are accounted for vary per institute, per tumor (group) and even per patient; partly because of actual differences in geometric treatment characteristics and partly as a result of different views. Consistent management of geometric uncertainties within and across institutes is important for establishing accurate dose-effect relations, as well as an unambiguous relationship between technology advancement and margin reduction or dose prescription for optimal treatment. Therefore, a unified perspective on geometric accuracy (with)in radiosurgery and stereotactic radiotherapy is warranted. By reviewing and comparing the different views, management and nature of geometric uncertainties in the chains of radiosurgery and stereotactic radiotherapy, we aim to contribute to such a unified perspective.

The reason I found this presentation particularly interesting is that it highlights the importance of continuing the work on our own project “Key factors influencing the outcome of Stereotactic Radiation Therapy – analysis, evaluation and validation” which was generously supported financially by Cancerföreningen i Stockholm.

– New radiobiology for severe/extreme hypo: abandoning the LQ model or integrating it? by M.C. Joiner (Wayne State University, Radiation Oncology, Detroit, USA). Prof. Joiner presented a very comprehensive description of the well-known Linear-Quadratic (LQ) model for radiation cell killing and a thorough review of the clinical and experimental evidence that the LQ model becomes less reliable at doses per fraction < 1 Gy, due to possible low-dose hyperradiosensitivity, and also at > 6 Gy per fraction for reasons not yet understood though increasing vascular damage and immunological/inflammatory effects occur at higher doses per fraction.

To conclude, once again participating to the ESTRO conference provided the opportunity for direct interaction with other scientists and for exchange of valuable information, some of which will hopefully be included into my current research projects. I would therefore like to thank the Cancerföreningen i Stockholm for the financial support that allowed me to attend this edition of the ESTRO Forum.