ESTRO 2022 - Abstract Book

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Abstract book

ESTRO 2022

Nausea is a common symptom in patients irradiated for brain tumors The dorsal vagal complex (DVC) located in the brainstem (BS) has been identified as the center of nausea and vomiting. The objective of our study was to determine a threshold dose at the DVC inducing nausea or vomiting in patients irradiated for benign brain tumors. Materials and Methods Between December 2017 and January 2021, 102 consecutive patients were irradiated for benign brain tumors, with normofractionated VMAT technique, without chemotherapy, at the Bordeaux University Hospital,. DVC delineation was performed on T1 sequences with gadolinium injection using the reference atlas [Beddok et al. RO 2019]. Quality control of delineation was performed for the first 10 patients by 5-radiation oncologists with Kappa index analysis. Nausea symptoms and anti-nausea treatments were collected at each weekly consultation during the radiotherapy treatment. Dosimetric criteria were analyzed for DVC, CT, and brain, and compared between groups of patients with and without nausea Results Among 102 patients, 68 were women, median age 61.5 years. The tumors treated were mainly meningiomas (80%) and neurinomas (17%). Regarding delineation quality control, Kappa index was 0.67 for a volume of 0.13cm3, reflecting a correct agreement on DVC contours comparable to Beddok et al [RO 2019]. The median dose was 54Gy [48.6-57.6Gy]. Out of 102 patients, 40 (39.2%) had nausea requiring anti-nausea treatment for 23 (57.5%) patients Women accounted for 77% in the nausea group and 60% in the non nausea group (p=0.06). In the group of patients with nausea, all volumes (VxGy) of DVC and TC irradiated were significantly higher for all parameters collected (V10-V20-V30-V40, mean, median dose) except V50 compared to asymptomatic patients. There was no significant difference for the brain dosimetric criteria. For patients without and with nausea, the mean DVC dose was 8.9Gy versus 21.6Gy (p<10 -4 ), respectively, and the mean brainstem dose was 16.9Gy versus 27.1Gy (p<10 -3 ). DVC mean dose is more predictive of nausea than brainstem dose. Below a DVC mean dose of 10Gy, 22% of patients are at risk of radiation induced nausea, compared to 60% above 10Gy (p=0.0001). Conclusion The mean DVC dose is significantly associated with radiation-induced nausea. A dose constraint below 10Gy to decrease the incidence of radiation-induced nausea needs to be validated by a prospective study. A. Dasgupta 1 , A. Thomas Alex 1 , A. Sahu 2 , U. Agarwal 2 , A. Chatterjee 1 , S. Goswami 3 , U. Gaikwad 1 , N. Bano 1 , V. Singh 4 , P. Shetty 4 , A. Moiyadi 4 , A. Sahay 5 , E. Sridhar 5 , A. Choudhari 2 , K. Bhattacharya 2 , R. Kinhikar 6 , R. Jalali 1 , T. Gupta 1 , J.S. Goda 1 1 Tata Memorial Centre, Radiation Oncology, Mumbai, India; 2 Tata Memorial Centre, Radiodiagnosis, Mumbai, India; 3 Tata Memorial Centre, Neuropsychology, Mumbai, India; 4 Tata Memorial Centre, Neurosurgery, Mumbai, India; 5 Tata Memorial Centre, Neuropathology, Mumbai, India; 6 Tata Memorial Centre, Medical Physics, Mumbai, India Purpose or Objective Radiation doses to the hippocampus have been linked to neurocognitive outcomes in primary brain tumors and brain metastasis treated with radiotherapy (RT). Hippocampus has extensive neural connections to the surrounding structures, including the amygdala and parahippocampal gyrus (PG), which are known to play a crucial role in emotional response and memory encoding. However, clinical data is lacking on the impact of RT doses on these structures, which led to the current study investigating the effect of doses on memory functions. Materials and Methods Adults (>18 years) with pituitary adenoma receiving intensity-modulated radiotherapy RT (45Gy/25fractions/5weeks) were accrued on a phase 2 prospective study. No definitive dose-constraints were applied to the hippocampus, amygdala, or PG, although as low as reasonably achievable (ALARA) principle was followed. The amygdala and PG on the left and right sides were drawn on T1-weighted 3D-FSPGR (slice thickness 1 mm) based on the consensus of two neuroradiologists. Dose parameters were extracted for the individual volumes. A dedicated neuropsychologist performed the memory evaluation using Wechsler Memory Scale, pre-RT, at 6 &18 months post-RT. We evaluated the 18-month scores, and a drop > 5% was considered clinically relevant. Shapiro-Wilk test was used for normality of data. Independent t-test and Mann-Whitney tests were done to correlate memory quotient (MQ) with sub-volume dosimetric data. A p-value of <0.05 was considered statistically significant. Results Nineteen patients were analyzed for dose correlation with memory function. Nine patients had a drop of >5% from the baseline. Of the four structure sets from both sides, only the dose-parameters from the left amygdala had a significant correlation with the memory outcomes at 18 months. The mean values of doses to the left amygdala for the two outcome groups (>5% vs ≤ 5% drop) were: mean dose 37.8 Gy vs 31.2 Gy (p=0.05), D30 40.1 Gy vs 33.3 Gy (p=0.04), D40 39.1 Gy vs 32.1 Gy (p=0.04), and D60 37.0 Gy vs 29.8 Gy (p=0.04). OC-0927 Impact of radiation doses to parahippocampal gyrus and amygdala on memory in pituitary adenomas