Innovative image-guided CyberKnife stereotactic radiotherapy for bladder cancer.

CyberKnife stereotactic body radiation therapy is used to treat extracranial tumour sites that move with respiration. It has also been employed for the successful treatment of prostate cancer, using the image-tracking CyberKnife system to compensate for intrafraction movements resulting from peristaltic motion and bladder filling. Large sporadic motions can be compensated for using an online target motion monitoring and cybernetic correction strategy. Radio-opaque gold markers can be implanted in the bladder during transurethral resection and used for online image-tracking during radiation to compensate for bladder filling and target movements. Transurethral bladder resection followed by chemoradiation and a stereotactic CyberKnife radiotherapy boost seems a promising approach for the treatment of invasive bladder cancer in heavily pre-treated patients or patients eligible for preservation strategies. In this case study of a patient with a previously irradiated pelvis, CyberKnife radiotherapy was feasible and well tolerated, with disease control and non-altered functional results two years after treatment completion. CyberKnife irradiation may also be considered for the conservative treatment of locally advanced T2-T4a N(0) M(0) bladder cancer with incomplete or uncertain transurethral resection.