A dose-escalation trial with the adaptive radiotherapy process as a delivery system in localized prostate cancer: analysis of chronic toxicity.

Purpose: To evaluate the validity of the chosen adaptive radiotherapy (ART) dose-volume constraints while testing the hypothesis that toxicity would not be greater at higher tumor dose levels.

Materials And Methods: In the ART dose escalation/selection trial, treatment was initiated with a generic planning target volume (PTV) formed as a 1-cm expansion of the clinical target volume (CTV). After the first week of therapy, the patient was replanned with a patient-specific PTV, constructed with CT and electronic portal images obtained in the first 4 days of treatment.