Concomitant boost radiotherapy for muscle invasive bladder cancer.
ABSTRACT To evaluate the feasibility and efficacy of a concomitant partial bladder boost schedule in radiotherapy for invasive bladder cancer, coupling a limited boost volume with shortening of the overall treatment time.
Between 1994 and 1999, 50 patients with a T2-T4 N0M0 transitional cell carcinoma of the bladder received radiotherapy delivered in a short overall treatment time with a concomitant boost technique. With this technique a dose of 40 Gy in 2-Gy fractions was administered to the small pelvis with a concomitant boost limited to the bladder tumor area plus margin of 15 Gy in fractions of 0.75 Gy. The total tumor dose was 55 Gy in 20 fractions in 4 weeks. Toxicity was scored according to EORTC/RTOG toxicity criteria.
The feasibility of the treatment was good. Severe acute toxicity >/=G3 was observed in seven patients (14%). Severe late toxicity >/=G3 was observed in six patients (13%). Thirty-seven patients (74%) showed a complete and five (10 %) a partial remission after treatment. The actuarial 3-year freedom of local progression was 55%.
In external radiotherapy for muscle invasive bladder cancer a concomitant boost technique coupling a partial bladder boost with shortening of the overall treatment time provides a high probability of local control with acceptable toxicity.
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ABSTRACT: The purpose of this study was to review the magnitude of contribution of chemotherapy (CT) in the local control of muscle invasive bladder carcinoma in the studies where a combined radio-chemotherapy (RCT) was used (how much higher local control rates are obtained with RCT compared to RT alone). Studies on radiotherapy (RT) and combined RCT, neo-adjuvant, concurrent, adjuvant or combinations, reported after 1990 were reviewed. The mean complete response (CR) rates were significantly higher for the RCT studies compared to RT-alone studies: 75.9% vs 64.4% (Wilcoxon rank-sum test, P = 0.001). Eleven of the included RCT studies involved 2-3 cycles of neo-adjuvant CT, in addition to concurrent RCT. The RCT studies included the one-phase type (where a full dose of RCT was given and then assessment of response and cystectomy for non-responders followed) and the two-phase types (where an assessment of response was undertaken after an initial RCT course, followed 6 wk later by a consolidation RCT for those patients with a CR). CR rates between the two subgroups of RCT studies were 79.6% (one phase) vs 71.6% (two-phase) (P = 0.015). The average achievable tumour control rates, with an acceptable rate of side effects have been around 70%, which may represent a plateau. Further increase in CR response rates demands for new chemotherapeutic agents, targeted therapies, or modified fractionation in various combinations. Quantification of RT and CT contribution to local control using radiobiological modelling in trial designs would enhance the potential for both improved outcomes and the estimation of the potential gain.World journal of radiology. 08/2013; 5(8):267-74.
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ABSTRACT: Purpose: Bladder tumor delineation and localization during treatment are challenging problems in radiotherapy for bladder cancer. The purpose of this study is to investigate improvement of tumor delineation by the fusion of cystoscopy images with the planning CT-scan using lipiodol markers injected around the visible tumor during cystoscopy.Methods: A registration method was developed for the fusion of cystoscopy images with a planning CT-scan and was tested on a phantom and retrospectively on the imaging data of four bladder cancer patients. For the patients, small deposits of lipiodol were injected at the visible margin of the tumor or previous transurethral resection site during cystoscopy. These deposits were clearly visible on the planning CT-scan and served as markers for both tumor delineation and image guidance of the radiotherapy treatment. Here, the markers were used for the registration of cystoscopy images with the planning CT-scan. The registration procedure works as follows: First, coarse registrations were made to orient the cystoscopy image correctly, using the center of gravity of the markers, the center of the CT bladder, and one of N markers as fiducial points in a point matching procedure. Starting from these N orientations, full registrations are performed taking lens deformation into account. Since a cystoscopy image is 2D, each pixel corresponds to a line-of-sight. The distances between the CT markers and the lines-of-sight of the cystoscopy markers were minimized. The final cost function (the root mean square distance between corresponding CT markers and lines-of-sight) was used to quantify the quality of the registration. The registration with the lowest final cost was considered to represent the correct orientation. The CT-based tumor delineation was finally backprojected onto the cystoscopy image.Results: The fusion of cystoscopy images with a planning CT-scan succeeded for the phantom and three out of four patients. The fiducial registration error (FRE) for the phantom image registration based on five markers was 1.1 mm, while the target registration error was 1.2-1.7 mm. The FREs for the patient images were 0.1-3.6 mm. The registration procedure failed for one patient, since it was not possible to indicate unambiguously the corresponding lipiodol marker locations in the cystoscopy image and the planning CT-scan. The difference between the CT and cystoscopy defined tumor outlines clearly exceeded the registration accuracy.Conclusions: Registration of cystoscopy images and planning CT-scan is feasible and allows for improvement of tumor delineation. However, the lipiodol injection protocol needs to be improved to facilitate identification of markers on both cystoscopy images and planning CT-scans.Medical Physics 05/2013; 40(5):051713. · 2.91 Impact Factor
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ABSTRACT: Radical cystectomy is the gold standard treatment of invasive bladder carcinoma, but conservative treatment is a serious option for selected patients. It comprises a transurethral resection, as complete as possible, before a radiation therapy of the whole bladder and pelvis, with a concomitant chemotherapy. Bladder wall movements during the treatment course lead to the use of wide margins to cover the clinical target volume. Planning target volume margins must be anisotropic to correspond to the mobility of each bladder zone: 10mm in the inferior portion, 15mm in lateral directions, and 20 to 25mm in anterior and superior directions. The development of image-guided radiotherapy and adaptative radiotherapy should lead to a reduction of these margins. Besides, partial bladder radiotherapy is showing encouraging results, by reducing the clinical target volume in well-selected patients.Cancer/Radiothérapie 08/2013; · 1.48 Impact Factor