ESTRO 2023 - Abstract Book

S1163

Digital Posters

ESTRO 2023

These were planned with VMAT to receive a prophylactic dose of 45 Gy in 25 fractions. Clinical dose constraints included rectum (V30 Gy<80%), bowel (V45 Gy<139 cm3), kidney (mean dose <15 Gy), duodenum (V55 Gy<15cm3) and spinal cord (Dmax <50 Gy). Results The primary station lymph node was recorded in 23/39 patients (59%). Most primary station nodes (84%) were in the pelvis, with 16% located beyond in the pre-sacral and common iliac regions (Figure 1). The involved lymph node detection rate was 8% on pre-operative imaging versus 28% of SLN mapping. In the dosimetric study, extending the radiotherapy target volumes from PTV A-C met the PTV and OAR constraints used in clinical practice.

Conclusion SLN mapping improved involved node detection from 8% to 28%. Most primary station nodes were in the pelvis, however, 16% were found beyond traditional EBRT target volumes in the pre-sacral and common iliac regions. From a dosimetric perspective, extending target volumes to include these areas met clinical dose constraints. Whilst further work is required to understand the therapeutic benefits and associated toxicities in clinical practice, extended target volumes have the potential to reduce the risk of nodal recurrence for this patient group. 1) Concin N et al. ESGO/ESTRO/ESP guidelines for the management of patients with endometrial carcinoma. International Journal of Gynecologic Cancer. 2021 Jan 1;31(1).

2) Kumar S et al. Prospective assessment of the prevalence of pelvic, paraaortic and high paraaortic lymph node metastasis in endometrial cancer. Gynecologic oncology. 2014 Jan 1;132(1):38-43.

Poster (Digital): Biomarkers

PO-1437 Radiomics as prognostic factor in locally advanced cervix cancer

S. Pedraza 1 , P. Sarandeses 2 , C. Romero 3 , J.F. Pérez-Regadera 4

1 HOSPITAL UNIVERSITARIO 12 DE OCTUBRE, RADIATION ONCOLOGY, MADRID, Spain; 2 Hospital Universitario 12 de Octubre, Nuclear Medicine, Madrid, Spain; 3 Hospital Universitario 12 de Octubre, Clinical Research Unit., Madrid, Spain; 4 Hospital Universitario 12 de Octubre, Radiation Oncology, Madrid, Spain Purpose or Objective Radiomics has emerged as a new tool in predicting prognosis. Our purpose was to analyze the role of SUVmax (maximum standardized uptake value), MTV (metabolic tumor volume) and TLG (total lesion glycolysis) from primary tumor as well as texture analysis in predicting response to treatment in locally advanced cervix cancer (LACC). Materials and Methods We performed a retrospective study with 116 patients with LACC treated with chemoradiotherapy. Radiomics parameters were extracted from 18F-FDG-PET/CT at diagnosis using a threshold relative to 41% of SUVmax uptake for tumor segmentation. 43 metabolic parameters were extracted: SUVmax, MTV, TLG, shape indexes, histogram statistics, second-order parameters derivered from Gray-level Co-occurrence Matrix (GLCM) and high-order indexes derivered from Gray-level Size-Zone Matrix (GLSZM), Gray-level Run Length Matrix (GLRLM) and Neighborhood Gray-Level Difference Matrix (NGTDM). Metabolic parameters cut-off points were extracted through ROC curves and Youden´s Index. Survival analysis was estimated with Kaplan-Meier method and Cox regression. Overall survival (OS) was considered between the end of radiotherapy (RT) and death date; disease-free survival (DFS) as the time between the end of RT and the relapse or disease progression. P value <0.05 was considered statistically significant. StataCorp software (V16.1) was used. Results Median follow-up investigation was 5.96 years (0.10-10.88). Median age patients was 50 years (25-84). FIGO stages were: IB2=0.86%(1), IB3=8.62%(10), IIA1=0.86%(1), IIB=18.97%(22), IIIB=6.9%(8), IIIC1=45.69%(53), IIIC2=15.52%(18), IVA=2.59%(3). Histologies included were squamous carcinoma=78.54%(91), adenosquamous=1.72%(2), adenocarcinoma=19.83%(23). All patients received radiotherapy treatment with weekly cisplatin and brachytherapy (n=114) or external RT (n=2) as tumor boost.