To demonstrate that radiotherapy treatments for bladder cancer can be delivered with greater accuracy using a new planning method and that this method can be used simply and effectively by those delivering treatment.

This study integrates a novel adaptive planning methodology, Adaptive-Planning Organ LOcalisation (A-POLO), with optimised margins and cone beam CT technology for improving the accuracy of radiotherapy treatment delivery.

The previous study (CCR2873, REC 07/Q0801/13) evaluated the use of cone beam CT in radiotherapy for bladder cancer. A larger than expected number of bladder radiotherapy treatments were seen to have been delivered with some element of geographic miss. Using the novel adaptive planning method these fractions of radiotherapy could have been correctly treated. The feasibility of this method has been proven in the previous study, particularly it has been shown that this method is appropriate and provides a simple solution to the problem. It can be carried out by the radiographers at the treatment unit without adding extra time to the treatment.

Inclusion Criteria:

• Age > 18
• Histologically confirmed invasive carcinoma of the bladder
• Patient planned to receive hypofractionated radiotherapy to the bladder.
• No previous pelvic radiotherapy
• Written informed consent given according to ICH/GCP and national/local regulations.

Exclusion Criteria:

• Urinary catheter in situ: the presence of a urinary catheter degrades cone beam image quality and thus images would not be evaluable. Patients with a urinary catheter would not be expected to show variation in bladder filling.