Normal Tissue Complication Probability (Ntcp) Model For Erectile Dysfunction (Ed) Following External Beam Radiotherapy (Rt) For Prostate Cancer.

135Background: ED remains a common toxicity of prostate RT despite technological advances. Penile bulb (PB) dose has been proposed as a predictor of ED post RT. The main objective of this study was to develop NTCP models for ED. Methods: 162 men treated within the CHHiP IGRT substudy (CRUK/06/16) had baseline clinical data, PB dosimetric data u0026 evaluation of ED using EPIC-26 at least 3 years post RT. Planning CT and reference dose distributions were imported into analysis software (VODCA, MSS GmbH) and PB retrospectively contoured by one clinician. The defined endpoint (severe ED) was a standardised average value of 0-33 for EPIC-26 sexual domain. Predictive models of ED were generated using PB dose in EQD2 (α/β ratio = 3Gy) u0026 clinical data (age, diabetes, hypertension, NCCN risk group, baseline PSA, hormone therapy, IGRT, margin size, PB volume). Multivariate logistic regression method using resampling methods was applied to select model order and parameters. Models were fitted using logistic regression ...