ESTRO 2022 - Abstract Book

S1125

Abstract book

ESTRO 2022

73.4%), FL/FOLFOX/FOLFIRI (n=8, 8.2%), and CapeOX(n=18, 18.4%). All patients received surgical intervention in 12 weeks, after finishing RT. 54%(n=53) of all patients were good responders, while 46%(n=45) were poor responders. The 3-year overall OS was 87.6% for the good responders, 70.8% for the poor responders, respectively ( p = .001). The 3- year overall DFS was 86.8% for the good responders, 59.3% for the poor responders, respectively ( p = .001). Predictors of good response on univariate LR, included volumetric modulated arc therapy (VMAT) use , RT with simultaneous integrated boost (SIB) with a CTV_H dose over 52Gy to gross tumor , higher CTV_H dose and an initial CEA concentration <5.0ng/mL . On multivariate LR, RT with SIB with a CTV_H dose over 52Gy to gross tumor ( OR 9.692; 95% CI 2.791-33.660; p = .000) and pre-treatment CEA level <5.0ng/mL ( OR 0.172; 95% CI 0.058-0.509; p = .001) remained significantly associated with good pathologic response.

Conclusion For patients with locally advanced rectal cancer, good response to neoadjuvant treatment is associated with better OS and DFS . RT with SIB in long course radiotherapy may improve the treatment response with tolerable acute toxicity.

Poster (digital): Gynaecological

PO-1330 Radical chemoradiotherapy for cervical cancer: current practice and avenues for future investment

O. Houlihan 1,2 , M. Byrne 3 , G. Workman 3 , S. Esteve 3 , U. McGivern 1 , A. Drake 1 , E. Baird 1

1 Northern Ireland Cancer Centre, Belfast City Hospital, Clinical Oncology, Belfast, United Kingdom; 2 Queen's University Belfast, School of Medicine, Dentistry and Biomedical Sciences, Belfast, United Kingdom; 3 Northern Ireland Cancer Centre, Belfast City Hospital, Radiotherapy Medical Physics, Belfast, United Kingdom

Purpose or Objective