ESTRO 2024 - Abstract Book

S4626

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTR0 2024

LETd distributions in the brainstem and spinal cord depended on the field configurations and the position of the distal edges of fields. Therefore, variations in LETd were seen across different centers planning proton therapy. For complex cases, the tumor location might make placement of distal edges in the brainstem or spinal cord unavoidable.

Keywords: Pediatrics, CNS tumors, Linear Energy Transfer

References:

1. Hahn C, et al., Acta Oncol. 2022 Oct ;61(2):206-214. doi:10.1080/0284186X.2021.1992007

2. Haas-Kogan D et al., Int J Radiat Oncol Biol Phys. 2018 May 1;101(1):152-168. doi: 10.1016/j.ijrobp.2018.01.013

3. Unkelbach J et al., Int J Radiat Oncol Biol Phys. 2016 Dec 1;96(5):1097-1106. doi: 10.1016/j.ijrobp.2016.08.038

4. McMahon SJ. Phys Med Biol. 2021 Feb 17;66(4):04NT02. doi: 10.1088/1361-6560/abda98

1343

Digital Poster

Exploring the safety and efficacy of proton radiotherapy for breast cancer in pregnant women

Menke Weessies, Murillo Bellezzo, Britt J. P. Hupkens, Frank J.W. Verhaegen, Gloria Vilches Freixas

Maastro, Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, Maastricht, Netherlands

Purpose/Objective:

Cancer poses a significant medical challenge for any individual, but the complexity multiplies when it strikes pregnant women. The delicate balance between providing effective cancer treatment to the mother while safeguarding the health of the developing fetus demands innovative solutions in oncology. During pregnancy, encountering cancer remains a rare yet distressing event, affecting approximately 1 in 1,000-2,000 pregnancies worldwide. [1-6] Breast cancer is currently one of the most diagnosed cancers during pregnancy. [7] It has a relatively low incidence but the potential for increased prevalence due to delayed pregnancies. [8] An increasing amount of research supports the safe use of chemotherapy, leading to approximately half of pregnant patients choosing this option, while radiation therapy utilization has decreased to just 2%. [7] This is likely a result of limited research. Most information about the biological effects of prenatal irradiation comes from studies of pregnant survivors of atomic bomb detonations, nuclear accidents, small study groups, and animal experiments. [9, 10] Fetus radiation doses below 100mSv are considered a safe threshold for deterministic effects during all stages of pregnancy. [10-16] Nevertheless, it is important to note that the likelihood of stochastic effects is believed to increase linearly in proportion to the fetus radiation dose, without a distinct threshold. [17] In parallel to medical advances, pencil beam scanning (PBS) proton radiotherapy (proton-RT) has become a promising alternative for managing cancer during pregnancy, notably offering advantageous dosimetric characteristics and reducing normal tissue complications when compared to photon