Adaptive management of bladder cancer radiotherapy

Recently, the bladder preserving potential of radiotherapy for invasive bladder cancer (bladder RT) has been recognized, and there is a renewed interest to improve bladder RT. The pivotal problem in bladder RT is caused by organ motion: without image-guided radiotherapy (IGRT), generous margins in the range of 2-3 cm have to be applied to account for organ motion, implying large treatment volumes and dose-limiting toxicity. IGRT has the potential to substantially reduce those margins, and thereby reduce treatment volumes. This review summarizes the literature on organ motion and IGRT for bladder cancer, and several bladder-specific problems and IGRT strategies are discussed.