S641
Clinical – Head & neck
ESTRO 2026
increases with radiation dose to the CNS, especially among the youngest patients. There was no evidence of a surveillance bias. Further analyses will investigate the effect of dose fractionation, and irradiation
doses calculated over the whole CNS volume – with no significant variation of risks by exposure of different CNS regions (brain lobes and spine). A linear-quadratic model best fitted the data – with a curvature at doses >30 Gy (Figure). For each 10%-increment of the relative volume of the whole CNS irradiated, the HRs were 1.0 [0.9-1.1], 1.4 [1.3-1.6], 1.4 [1.3-1.5], 1.4 [1.3–1.5] and 1.3 [1.2-1.5] at dose levels of 0.1-10, 10-20, 20-30, 30- 40, and ≥ 40 Gy, respectively. The risk/Gy was the highest among youngest patients at first cancer diagnosis but did not vary according to first cancer type, or sex. We found no significant effect of chemotherapy, nor interaction between EBRT and chemotherapy. The HRs were unchanged after adjustment for the frequency of cerebral diagnostic examinations (MRIs, or CTs).
techniques. References:
1.Heymer, E.J., Hawkins, M.M., Winter, D.L. et al. Risk of subsequent gliomas and meningiomas among 69,460 5-year survivors of childhood and adolescent cancer in Europe: the PanCareSurFup study. 2.Withrow DR, Anderson H, Armstrong GT, et al. Pooled Analysis of Meningioma Risk Following Treatment for Childhood Cancer. JAMA Onco l. 20223. Taylor AJ, Little MP, Winter DL,et al. Population-based risks of CNS tumors in survivors of childhood cancer: the British Childhood Cancer Survivor Study. J Clin Oncol. 20104.Journy NMY, Zrafi WS, Bolle S, Fresneau B, Alapetite C, Allodji RS, et al. Risk Factors of Subsequent Central Nervous System Tumors after Childhood and Adolescent Cancers: Findings from the French
Childhood Cancer Survivor Study. 2021 Keywords: meningioma, ccs, radiotherapy
Poster Discussion 3948 A systematic analysis of the exact recurrence location after radiotherapy for laryngeal, hypopharyngeal and oropharyngeal cancer Cornelis P.J. Raaijmakers 1 , Barbara Paic 1 , Alexis Kotte 1 , Patricia A.H. Doornaert 1 , Christianus H.J. Terhaard 1 , Johannes Rijken 2 , Remco de Bree 2 , Jan Willem Dankbaar 3 , Frank A Pameijer 3 , Mischa de Ridder 1 1 Radiation Oncology, University Medical Center, Utrecht, Netherlands. 2 Head and Neck Surgical Oncology, University Medical Center, Utrecht, Netherlands. 3 Radiology, University Medical Center, Utrecht, Netherlands
Purpose/Objective: Recurrence of disease after head-and-neck
radiotherapy occurs in 15-40% of patients. It is known that the majority of recurrences are located close to the original tumor location. However, the exact recurrence location in relation to the target volumes has never been systematically analyzed. The aim of this work was to precisely determine the recurrence locations after radiotherapy for laryngeal, hypopharyngeal and oropharyngeal cancer in order to evaluate the adequacy of the applied margins. Material/Methods: Recurrence locations after primary laryngeal, hypopharyngeal and oropharyngeal cancer radiotherapy were analyzed for patients treated between October 2016 and September 2022 at the University Medical Center Utrecht. Patients with
Conclusion: This study confirms that the risk of meningioma
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