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.

[State of the art and advances in radiotherapy for bladder cancer]. / Techniques et innovations en radiothérapie pour le traitement conservateur des cancers infiltrants localisés de vessie.

Radical cystectomy is the treatment of choice for nonmetastatic, muscle-infiltrating bladder cancer. However, bladder-sparing approaches can be discussed in carefully selected patients. Bladder-preservation protocols aim to guaranty local control and survival with a functional bladder and a good quality of life. Such strategies include combinations of transurethral resection and radiochemotherapy, partial cystectomy and brachytherapy, radiotherapy-cystotomy and electrontherapy. Strict selection criteria and close follow-up are mandatory. New irradiation techniques hold the promise to improve local control by selectively boosting the dose to the tumor while better sparing the organs at risk. Such advances include the use of multimodal imaging, image-guided radiotherapy, concomitant boost with conformal irradiation+/-intensity modulated radiation therapy. Brachytherapy, either high-dose or pulsed-rate, is a promising technique for selected cases. Highly-conformal irradiation with tumor tracking using the Cyberknifetrade mark technology may also provide opportunities to boost the tumor while reducing toxicities. Specific innovative irradiation techniques are discussed.