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Background: Prospective trials have demonstrated the advantage of dose-escalated radiotherapy for the biochemical and clinical control of intermediate risk prostate cancer. Dose escalation improves outcomes but increases risks of urinary and bowel toxicity. Recently the contribution of "spacers" positioned in the septum between the rectum and the prostate could improve the functional results of intensity modulated radiation therapy (IMRT). To date most of the evaluated devices were polyethylen glycol (PEG) and hyaluronic acid (HA). Men on the Spacer arm had decreased bowel toxicity and less decline in both urinary and bowel quality of life as compared to Control men in a randomized trial.Methods: This is an interventional, multi-center study to evaluate the use of biodegradable inflatable balloon for patients with intermediate risk prostate cancer treated by IMRT (74 to 80 Gy, 2 Gy/fraction) with daily image guided radiotherapy.Discussion: This multicenter prospective study will yield new data regarding dosimetric gain and implantation stages of Bioprotect balloon. Acute and late toxicities and quality of life will be registered too.Trial Registration: NCT02478112 , date of registration: 15/06/2015. [ABSTRACT FROM AUTHOR]

Background: Currently, there is no standard option for local salvage treatment for local prostate cancer recurrence after radiotherapy. Our objective was to investigate the feasibility and efficiency of Robotic Stereotactic Body Radiation Therapy (SBRT) in this clinical setting.Methods/materials: We retrospectively reviewed patients who were treated at our institution with SBRT for local prostate cancer recurrence after External Beam Radiation Therapy (EBRT) or brachytherapy. Multidisciplinary staff approved the treatment, and recurrence was biopsy-proven when feasible. A dose of 36 Gy was prescribed in six fractions. Treatment was delivered every other day.Results: Between August 2011 and February 2014, 23 patients were treated with SBRT for intra-prostate cancer recurrence with a median follow up of 22 months (6 to 40). Twenty patients had biopsy-proven recurrence. For 19 patients, EBRT was the initial treatment and in four patients, brachytherapy was the initial treatment; the median relapse-time from initial treatment was 65 months (28 to 150). At relapse, 10 patients had an extra-capsular extension. Fourteen patients were treated with androgen deprivation that could be stopped after a median of 1 month after SBRT (range 0-24). A PSA decrease occurred in 82.6% of the patients after SBRT. The 2-year disease-free survival and overall survival rates were 54 and 100%, respectively. Disease progression was observed for nine patients (39.1%) (five local, three metastatic and one nodal progression) after a median of 20 months (7-40 months). The median nadir PSA was 0.35 ng/ml and was achieved after a median of 8 months (1 to 30) after treatment. We observed no grade 4 or 5 toxicity. Two patients presented with grade 3 toxicities (two Cystitis and one neuralgia). Other toxicities included urinary toxicities (five grade 2 and nine grade 1) and rectal toxicities (two grade 2 and two grade 1).Conclusion: SBRT for local prostate cancer recurrence seems feasible and well tolerated with a short follow up. Prospective evaluation is needed. [ABSTRACT FROM AUTHOR]

Background: Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT).Methods: The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation.Results: Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV coverage and the sparing of the lung and heart. However, the CK may be used to reduce high doses received by the NTBTV more efficiently.Conclusions: Robotic stereotactic radiotherapy may be used for APBI to more efficiently spare the NTBTV and improve cosmetic results of APBI. [ABSTRACT FROM AUTHOR]

Background: Cone-beam computed tomography (CBCT) image-guided radiotherapy (IGRT) systems are widely used tools to verify and correct the target position before each fraction, allowing to maximize treatment accuracy and precision. In this study, we evaluate automatic three-dimensional intensity-based rigid registration (RR) methods for prostate setup correction using CBCT scans and study the impact of rectal distension on registration quality. Methods: We retrospectively analyzed 115 CBCT scans of 10 prostate patients. CT-to-CBCT registration was performed using (a) global RR, (b) bony RR, or (c) bony RR refined by a local prostate RR using the CT clinical target volume (CTV) expanded with 1-to-20-mm varying margins. After propagation of the manual CT contours, automatic CBCT contours were generated. For evaluation, a radiation oncologist manually delineated the CTV on the CBCT scans. The propagated and manual CBCT contours were compared using the Dice similarity and a measure based on the bidirectional local distance (BLD). We also conducted a blind visual assessment of the quality of the propagated segmentations. Moreover, we automatically quantified rectal distension between the CT and CBCT scans without using the manual CBCT contours and we investigated its correlation with the registration failures. To improve the registration quality, the air in the rectum was replaced with soft tissue using a filter. The results with and without filtering were compared. Results: The statistical analysis of the Dice coefficients and the BLD values resulted in highly significant differences (p<10-6) for the 5-mm and 8-mm local RRs vs the global, bony and 1-mm local RRs. The 8-mm local RR provided the best compromise between accuracy and robustness (Dice median of 0.814 and 97% of success with filtering the air in the rectum). We observed that all failures were due to high rectal distension. Moreover, the visual assessment confirmed the superiority of the 8-mm local RR over the bony RR. Conclusion: The most successful CT-to-CBCT RR method proved to be the 8-mm local RR. We have shown the correlation between its registration failures and rectal distension. Furthermore, we have provided a simple (easily applicable in routine) and automatic method to quantify rectal distension and to predict registration failure using only the manual CT contours. [ABSTRACT FROM AUTHOR]