In a radiation therapy method, one or more planning images are acquired (102) of a subject. Features of at least malignant tissue are contoured in the one or more planning images to produce one or more initial feature contours. One or more treatment images of the subject are acquired (114). The one or more initial feature contours are updated (122) based on the one or more treatment images. Radiation treatment parameters are optimized (126) based upon the updated one or more feature contours. Radiation treatment of the subject is performed (130) using the optimized parameters.