Abstract Book

ESTRO 37

S419

PO-0805 Prediction of outcome using pretreatment PET and MRI radiomics in locally advanced cervical cancer F. Lucia 1 , D. Visvikis 2 , O. Miranda 1 , M.C. Desseroit 2 , P. Robin 3 , O. Pradier 1 , M. Hatt 2 , U. Schick 1 1 CHRU Brest- Hôpital Morvan, Radiation oncology, Brest, France 2 LaTIM, LaTIM- INSERM, Brest, France 3 CHRU Breest- Hôpital Morvan, Nuclear Medicine, Brest, France Purpose or Objective The aim of this study was to determine if radiomics features from 18 F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) images could contribute to prognosis in cervical cancer. Material and Methods One hundred and two patients (69 for training and 33 for testing) with locally advanced cervical cancer (LACC) receiving chemoradiotherapy (CRT) from 08/2010 to 12/2016 were enrolled in this study. 18 F-FDG PET/CT and MRI examination (T1, T2, T1C, Diffusion-weighted imaging (DWI)) was performed for each patient before CRT. Primary tumor volumes were delineated with the fuzzy locally adaptive Bayesian algorithm in the PET images and with 3D Slicer TM in the MRI images. Radiomics features (intensity, shape and textural) were extracted and their prognostic value was compared with clinical parameters for recurrence-free and locoregional control. Results In the training cohort median follow-up was 3.0 years (0.43-6.56 range) and relapse occurred in 36% of patients. In univariate analysis, FIGO stage (I-II vs. III-IV) and metabolic response (complete vs. non complete) were probably associated with outcome without reaching statistical significance, contrary to several radiomics features from both PET and MRI sequences. Multivariate analysis in training test identified Grey Level Non Uniformity GLRLM in PET and Entropy GLCM in ADC maps from DWI MRI as independent prognostic factors. These had significantly higher prognostic power than clinical parameters, as evaluated in the testing cohort with accuracy of 94% for predicting recurrence and 100% for predicting lack of loco-regional control (versus ~50-60% for clinical parameters).

Conclusion In LACC treated with CRT, radiomics features such as Entropy GLCM and GLNU GLRLM from functional imaging DWI- MRI and PET respectively, are independent predictors of recurrence and loco-regional control with significantly higher prognostic power than usual clinical parameters. Further research is warranted for their validation which may justify more aggressive treatment in patients identified with high probability of recurrence. PO-0806 Cervical cancer stem cells and response to chemo-radiation in locally advanced cervical cancer. S. Sastri Chopra 1 , K. Deodhar 2 , J.S. Goda 3 , V. Pai 4 , S. Pant 1 , N. Rathod 4 , S. Waghmare 5 , U. Mahantshetty 6 , R. Engineer 6 , J. Ghosh 7 , S. Gupta 7 , S. Shrivastava 6 1 Advanced Centre for Treatment- Research and Education in Cancer, Radiation Oncology, Navi Mumbai, India 2 Tata Memorial Centre, Pathology, Mumbai, India 3 Advanced Centre for Treatment- Research and Education in Cancer, Radiation Oncology and Clinical Biology, Navi Mumbai, India 4 Advanced Centre for Treatment- Research and Education in Cancer, Clinical Biology, Navi Mumbai, India 5 Advanced Centre for Treatment- Research and Education in Cancer, Stem Cell Biology, Navi Mumbai, India 6 Tata Memorial Hospital, Radiation Oncology, Mumbai, India 7 Advanced Centre for Treatment- Research and Education in Cancer, Medical Oncology, Navi Mumbai, India Purpose or Objective While cancer stem cells (CSCs) have been reported across solid tumours, there is dearth of data regarding CSC and its prognostic role in patients undergoing chemoradiation for cervical cancer. The present study was designed to investigate protein expression of CSC in locally advanced cervical cancer. Material and Methods From October, 2013- December 2015, patients with locally advanced squamous cancer of cervix (Stage IB2- IIIB) were included in a prospective study designed to investigate expression of stem cell proteins. Pretreatment biopsy was obtained and immunohistochemistry (IHC) was performed for Embryonic Stem cells (ESC) and CSCs. IHC was performed for SOX-2, OCT-4, Nanog (ESC), CD44 and Podoplanin expression. Semi-quantitative scoring was used for IHC. Protein expression was considered positive if there was nuclear staining for ESC and membranous or cytoplasmic staining for CSCs.CD44 positive samples were considered to be CSC + if it was coexpressed with ESC. CD44 expression in absence of ESC was regarded as noncontributory. All patients received uniform concurrent radiation and brachytherapy to an equivalent dose of >80 Gy to point A with concurrent weekly cisplatin. Correlation of CSC expression was performed with known prognostic factors and local relapse and disease free survival (DFS). p <0.05 was considered statistically significant.