RT Journal Article SR Electronic T1 85 Response to concurrent external beam radiotherapy and chemotherapy as a new predictor for overall survival in locally advanced cervical cancer – a retroembrace study nomogram JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A45 OP A45 DO 10.1136/ijgc-2019-IGCS.85 VO 29 IS Suppl 3 A1 A Sturdza A1 R Pötter A1 M Kossmeier A1 U Mahantshetty A1 K Kathrin A1 C Haie-Meder A1 JC Lindegaard A1 I Jürgenliemk-Schulz A1 LT Tan A1 P Hoskin A1 E Van Limbergen A1 C Gillham A1 B Segedin A1 E Tharavichitkul A1 E Villafranca A1 L Fokdal A1 K Tanderup YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_3/A45.1.abstract AB Objectives To present a nomogram for prediction of overall survival (OS) in locally advanced cervical cancer patients (LACC) undergoing definitive radiochemotherapy including image guided adaptive brachytherapy (IGABT).Methods We retrospectively reviewed 720 patients with LACC acrrued onto the RetroEMBRACE database (12 international institutions). All patients were treated with External Beam Radiotherapy (EBRT) concurrent with Chemotherapy (CHT) and MRI/CT-guided brachytherapy. Missing data (7.2%) were imputed by multiple imputations and predictive mean matching. Stepwise selection of predictive factors with the Akaike information criterion (AIC) was used to obtain a predictive model and construct a nomogram for OS predictions 60 months from diagnosis. The model was internally validated by concordance probability as a measure of discrimination and a calibration plot (both corrected for optimism using bootstrap cross-validation).Results Through the predictive model (AIC), seven factors were selected to develop the nomogram: FIGO stage (2B vs.1A,1B,2A; 3A,3B,4A,4B vs.1A,1B,2A), age, corpus involvement, lymph node status, concurrent chemotherapy given, overall treatment time, volume of the high risk clinical target volume at the time of first brachytherapy (CTVHR). CTVHR is considered surrogate for response at concurrent EBRT+CHT. This OS nomogram had a satisfactory calibration and useful discrimination (concordance probability c=0.74).Conclusions Prognostic factors were used to develop the first nomogram for 5-year OS in patients with LACC in the setting of IGABT treatment. Response to concurrent EBRT and CHT (CTVHR) seems to be a new essential outcome predictor for OS. These nomograms can be used to better estimate individual and collective outcomes and may facilitate personalized patient counselling during the treatment.