ESTRO 2021 Abstract Book

S1651

ESTRO 2021

Conclusion This study, based on a single blood sample, provides the basis of an easy to perform, realistic, cost effective assay. It could be proposed to every patient intending to be treated with RT.

PO-1937 Tumours have a sex: relevance to the multifunctional oncoprotein Y-box binding protein-1 L. Marignol 1 , S. Croghan 2 , P. Rohan 2 , R. Manecksha 3 , T. Lynch 4 1 Trinity College Dublin , Radiation therapy , Dublin , Ireland; 2 St James's Hospital, Urology, Dublin , Ireland; 3 St James's Hospital and Trinity College Dublin , Urology / Surgery, Dublin, Ireland; 4 St James's Hospital / Trinity College Dublin , Urology / Surgery, Dublin , Ireland Purpose or Objective Disparities in treatment response between male and female patients are increasingly reported. The reason could lie with the fundamental biological differences between the sexes. Growing evidence report the impact of sex cancer biology. The Y-box binding protein-1 (YB-1) gene codes for a multifunctional oncoprotein that is increasingly being linked to the regulations of many aspects of cancer cell biology that affect the radiation response. In prostate cancer, our lab related nuclear detection in biopsy specimens to radiotherapy treatment failure in high-risk patients. This study aimed to examine the relationship between YB-1 mRNA levels and overall survival in male and female patients across cancer sites. Materials and Methods Kaplan-Meier curves for overall survival up to 60 months were generated from publicly available mRNA data of patients with bladder carcinoma (N=404), Head and Neck squamous cell carcinoma (n=599), Lung adenocarcinoma (n=513) and Rectum adenocarcinoma (n=165) extracted from a combination of the gene expression omnibus, gene expression archive and the Cancer Genome Atlas databases using Kmplot.com. Results YB-1 mRNA expression data for a cohort of 404 bladder cancer patients (106 female, 298 male) was not associated with worse overall survival (HR 1.2 (0.7-1.64) p=0.26). Analysis of the female cohort indicated a significant association between high YB-1 expression levels and improved overall survival when compared to female patients with low expression levels (0.43 (0.21-0.88), p=0.018). Analysis of the male cohort indicated a significant opposite association between high YB-1 expression levels and poor overall survival (1.58 (1.09-2.28), p=0.014). In the 499 Head and Neck cancer patients analysed (N=133 female, N= 366 male), high YB-1 mRNA levels were associated with poorer overall survival (1.59 (1.13-2.22), p=0.007). When separated according to sex, this association was confirmed in male (1.63 (1.08-2.46), p=0.019), but was just short of statistical significance in female patients (1.68 (0.99-2.85), p=0.52). In lung adenocarcinoma patients (N= 591; 270 females, 294 males), high expression was significantly associated with poorer overall survival (1.41 (1.04-1.9), p=0.024). This association was present in the female (1.63 (1.07 - 2.48), p=0.02) but not the male patient population (1.4 (0.89 - 2.19), p=0.14). In rectal cancer patients, YB-1 mRNA levels were not associated with overall survival (1.76 (0.75 - 4.12), p=0.18) when the sexes were combined. Similarly, no association was detected in male patients (0.43 (0.14 - 1.28), p=0.12). However, in female patients (N=75), high YB-1 mRNA levels were significantly associated with poorer overall survival (5.38 (1.57 - 18.44), p=0.002). Conclusion This study highlights that analysis of YB-1 mRNA levels according to sex can affect both the strength and the direction of associations with overall survival. Further evaluation of the relevance of these findings to specific response to radiotherapy are warranted.

Digital Poster: Patient preparation, positioning and immobilisation

PO-1938 Behind the mask: an overview of immobilisation equipment for Surface Guided Radiotherapy C. Dunlea 1 , T. Patel 2 , Y. Ch'ing Chang 3 1 University College London Hospital, Radiotherapy Department, London, United Kingdom; 2 University College London Hospital, Radiotherapy Department, London , United Kingdom; 3 University College London Hospital , Radiotherapy Department, London, United Kingdom