Intensity Modulated Radiation Treatments Followed by A Stereotactic CyberKnife Boost Focused on the Gross Residual Pelvic Tumor Volume

This register concerned patients with any kind of non-resected pelvic cancer for which a brachytherapy Gross Tumor Volume (GTV) boost is non indicated.

1. Placement of fiducials First of all, fiducials will be placed near or inside the Gross Tumor Volume (GTV).
2. Radiation treatment The radiation treatment will be delivered by Varian Rapid ARC accelerators. 50 Gy will be delivered in the Planning Tumor Volume (PTV) 1 and 60 Gy in the PTV 2 simultaneously in 28 fractions (5 fractions a week) in no more than 40 days. Anytime, 95% of the prescribed dose will have to cover at least 90% of the PTV 1 and PTV 2.
3. CK Boost pelvis In the following 14 days after the external beam treatment, two high CyberKnife dose sessions will deliver a pelvic boost of 6.5 Gy each to the initial GTV or eventually to the residual GTV in case of too close vicinity of the organs at risk (OAR). This boost will be planned according to a recent paper, using a new CT scan and MRI scan for planimetric purposes. 95% of the prescribed dose will have to cover at least 90% of the PTV. The maximal CyberKnife tolerated doses to the OAR for a 6.5 Gy dose will be 5 Gy to 2cc of the bladder, rectum or sigmoid structures and 2.5 Gy to 5 cc of the small bowel. The protocol will not require a dose summation of the different steps of the treatment. The total duration of the whole treatment will have to be inferior to 55 days.

4 Follow-up The clinical follow up will be planed weekly during the radiation treatments, and at 2, 4 and 6 months thereafter. The patients will be then followed up every 4 months during the first 2 years and twice yearly thereafter.

A medical imaging using PET Scanner and MRI when possible will be performed at least at 6 months intervals during the first 2 years.