To present a nomogram for prediction of overall survival (OS) in locally advanced cervical cancer pts (LACC) undergoing definitive radiochemotherapy (RCT) including image guided adaptive brachytherapy (IGABT). 720 pts with LACC treated with RCT including IGABT in 12 institutions (median follow-up 56 mths) were analyzed; 248 deaths occurred. Based on literature and expert knowledge, 13 candidate predictors for OS were a priori chosen. Missing data (7.2%) were imputed by multiple imputation and predictive mean matching. Univariate analyses (UA), multivariable Cox regression model (m-Cox) for OS stratified by center were applied to test for statistical significance and display the effect size with hazard ratios (HR). Stepwise selection of predictive factors with the Akaike information criterion (AIC) was used to obtain a predictive model and to construct a nomogram for OS predictions 60 months from diagnosis. This was internally validated by concordance probability as a measure of discrimination and a calibration plot (both corrected for optimism using bootstrap cross-validation). 13 potential predictive factors were evaluated; 10 reached statistical significance in UA (table 1) while histopathology, parametrial involvement and hydronephrosis did not reach significance. Four factors were confirmed significant with m-Cox, through the predictive model (AIC), seven factors selected to develop the nomogram, with satisfactory calibration and useful discrimination (concordance probability c=0.74). This is the first nomogram to predict OS in LACC patients treated with IGABT. In addition to previously reported factors such as age, FIGO stage, corpus involvement, chemotherapy delivery, overall treatment time (OTT) and lymph node involvement, response to EBRT and chemotherapy (volume of CTVHR at first BT) seems to be an essential outcome predictor. These results may facilitate individualized patient counseling during the treatment.Abstract 103; Table 1VariableUA HR and 95% CIm- Cox HR and 95% CIStepwise selection (AIC) HRAgelinear squared1.02 [1.01, 1.03]+0.95 [0.89, 1.02] 1.00 [1.00, 1.00]0.93 1.001Hemoglobin (diagnosis)g/dl0.86 [0.79, 0.94]+0.98 [0.88, 1.08]-FIGO Stage2B vs.1A,1B,2A1.73 [1.16, 2.57]∗Significant results (p<0.05), +Highly significant results (p<0.001), Hazard Ratio (HR), Confidence Interval (CI).1.62 [0.98, 2.67]1.503A,3B,4A,4B vs.1A,1B,2A4.15 [2.76, 6.25]+3.24 [1.80, 5.83]+2.53Tumour width (MRI)mm1.02 [1.01, 1.03]+1.00 [0.99, 1.01]-Corpus involvementyes vs. no1.48 [1.10, 1.98]∗Significant results (p<0.05), +Highly significant results (p<0.001), Hazard Ratio (HR), Confidence Interval (CI).1.17 [0.85, 1.60]+1.20Lymph nodesN1 vs. N01.47 [1.13, 1.89]+1.46 [1.10, 1.94]∗Significant results (p<0.05), +Highly significant results (p<0.001), Hazard Ratio (HR), Confidence Interval (CI).1.40Concurrent chemo.yes vs. no0.52 [0.39, 0.69]+0.59 [0.40, 0.87]∗Significant results (p<0.05), +Highly significant results (p<0.001), Hazard Ratio (HR), Confidence Interval (CI).0.64OTTmonths1.02 [1.01, 1.03]+1.01 [1.00, 1.02]1.01CTVHR Volume (BT)cm31.02 [1.01, 1.02]+1.01 [1.01, 1.02]+1.02CTVHR D90Gy0.97 [0.96, 0.98]+0.99 [0.98, 1.00]-∗ Significant results (p<0.05), +Highly significant results (p<0.001), Hazard Ratio (HR), Confidence Interval (CI). Open table in a new tab