ESTRO meets Asia 2024 - Abstract Book

S244

Interdisciplinary – Particle Therapy

ESTRO meets Asia 2024

9

Proffered Paper

Bone marrow sparing in post-operative gynaecological malignancies: Proton vs Photon Radiotherapy

Antje Wark 1,2 , Anil Gupta 3,4 , Eva Meixner 1,2 , Laila König 1,2 , Juliane Hörner-Rieber 1,2 , Tobias Forster 1,2 , Kristin Lang 1,2 , Malte Ellerbrock 5 , Klaus Herfarth 1,5 , Jürgen Debus 1,5 , Nathalie Arians 1,2 1 Department of Radiation Oncology, Heidelberg University Hospital, 69120, Heidelberg, Germany. 2 Heidelberg Institute of Radiation Oncology (HIRO), 69120, Heidelberg, Germany. 3 Clinical and Radiation Oncology, Subharti Institute of Cancer Managment and Research (SICMAR), Meerut, India. 4 Department of Radiation Oncology, All India Institute of Medical Science (AIIMS), New Delhi, India. 5 Heidelberg Ion-Beam Therapy Center (HIT), Heidelberg University Hospital, 69120, Heidelberg, Germany

Purpose/Objective:

More than one-half of the body’s bone marrow is located in the lumbar spine and pelvic skeleton 1 . There is a direct correlation between radiation exposure to bone and depletion of marrow 2 . The vulnerability of bone marrow to radiation poses a significant challenge, especially in the treatment of malignancies located in the pelvis. This study compares intensity-modulated proton therapy (IMPT) with the present standard of care intensity modulated photon radiotherapy (IMRT) for post-operative irradiation of uterine cervical and endometrial cancer. We aimed to evaluate whether IMPT reduces pelvic bone marrow exposure, thereby minimizing leukopenia and anemia, compared to IMRT. The secondary endpoint was the assessment of predictive parameters for the occurrence of sacral insufficiency fractures (SIF) when applying IMPT.

Material/Methods:

A total of 50 patients with cervical or endometrial cancer treated by postoperative radiotherapy at the Heidelberg Ion Therapy Center and the Department of Radiation Oncology of Heidelberg University Hospital between 2017 and 2023 were retrospectively selected for this comparative study. The experimental cohort consisted of uterine cervical (n=17) or endometrial cancer (n=8) patients treated by IMPT within the prospective APROVE trial 3 . A control cohort of 25 patients treated by IMRT with corresponding age, dose, and diagnostic characteristics was selected. Dosimetric parameters delivered to the whole pelvic skeleton and subsites (ilium, lumbosacral, and lower pelvis) and hematological toxicity were evaluated. For the IMPT group, the incidence of SIF was evaluated based on MRI follow-up.