Adrian Franklin

Hemi-gland focal low dose rate prostate brachytherapy: An analysis of dosimetric outcomes

BACKGROUND AND PURPOSE Advances in magnetic resonance imaging (MRI) and prostate sampling enable early identification of men with low to intermediate risk prostate cancer who are candidates for focal therapies that minimise side effects. We report dosimetry data from a pilot study evaluating the effectiveness of hemi-gland low dose rate (HG-LDR) brachytherapy as a focal therapy approach to control unilateral localised disease. MATERIAL AND METHODS Twenty-two men underwent HG-LDR brachytherapy. Multi parametric MRI and transperineal template mapping biopsies were used to identify low volume unilateral disease. Whole gland therapy controls (n=120) were retrospectively obtained. All implants were performed with 4D Brachytherapy. RESULTS Intraoperative and postimplant dosimetry complied with established brachytherapy parameters. Mean (standard deviation) postoperative D90 for the target hemi-gland was 153.8 (11.3) Gy compared to 47.5 (12.7) Gy for the contralateral hemi-gland (P<0.001). Mean postoperative V100% was 93.1 (3.9) and 24.6 (10.5) for the target and contralateral hemi-glands respectively (P<0.001). Urethra D30 was 150.4 (19.8) Gy and 174.2 (15.0) Gy for hemi-gland and whole gland implants respectively (P<0.001). Significantly reduced dose was also observed for rectum and neurovascular bundles. CONCLUSIONS HG-LDR focal brachytherapy is feasible with significant reduction in dose to the contralateral hemi-gland and organs at risk.

Improving the efficiency of image guided brachytherapy in cervical cancer

Brachytherapy is an essential component of the treatment of locally advanced cervical cancers. It enables the dose to the tumor to be boosted whilst allowing relative sparing of the normal tissues. Traditionally, cervical brachytherapy was prescribed to point A but since the GEC-ESTRO guidelines were published in 2005, there has been a move towards prescribing the dose to a 3D volume. Image guided brachytherapy has been shown to reduce local recurrence, and improve survival and is optimally predicated on magnetic resonance imaging. Radiological studies, patient workflow, operative parameters, and intensive therapy planning can represent a challenge to clinical resources. This article explores the ways, in which 3D conformal brachytherapy can be implemented and draws findings from recent literature and a well-developed hospital practice in order to suggest ways to improve the efficiency and efficacy of a brachytherapy service. Finally, we discuss relatively underexploited translational research opportunities.

EP-1219: A bespoke, flexible clinical database system for multicentre rectal carcinoma registry

and compared with log-rank tests.Since June 1993 until March 2013, 87 patients with the diagnosis of gallbladder cancer who underwent extended or simple cholecystectomy and were staged as T1b-2-3N0-1M0, received adjuvant radiochemotherapy at Instituto Oncológico, Viña del Mar. Overall survival and median survival were analyzed in relation to different prognostic factors, using Kaplan-Meier techniques and compared with log-rank tests. Results: With a median follow-up of 43 months (range: 5-180 months) the 5 and 10-year overall survival (OS) rate for the entire cohort was 44.9% and 36.8%, respectively, and the median survival time was 45 months. In the group who underwent extended cholecystectomy, the 5-year OS was 57.2% versus 31.2% for those who underwent simple cholecystectomy (p=0.032). The median survival time was 57 and 27 months for patients with extended cholecystectomy and simple cholecystectomy, respectively (p=0.032). Conclusions: After a complete resection, radiochemotherapy appears a good approach and can achieve a long term survival rate. This benefit is higher for those in which surgery is an extended cholecystectomy.

PO-1019: Improving service efficiency by reducing the volume of bowel contoured when performing IGBT of the cervix?

Purpose/Objective: Contouring the bowel is one of the most time consuming aspects of planning a HDR treatment of the cervix. This investigates the possibility of reducing the volume of bowel to be contoured for planning purposes when treating the Cervix with HDR using a Tandem and Ovoid Applicator with CT simulation. It is hoped that the service efficiency can be improved by reducing the volume of bowel contoured prior to planning. Materials and Methods: Additional contours were constructed on previous patient plans which were clinically accepted. Using Oncentra Brachy (Version 4.3), 3D margins of 0.5cm, 1.0cm, 1.5cm and 2.0cm were grown around the HRCTV. The overlap of the original (complete) bowel volume and the newly created volumes was extracted to produce a bowel contour which was limited to within a given distance from the HR-CTV. For example, taking the intersection of the ‘Bowel’ and the ‘HRCTV + 1.0cm’ to give a bowel contour which only extends to 1.0cm beyond the HR-CTV (referred to as ‘HR-CTV + 1.0cm & Bowel’) This produced a set of bowel outlines which were limited to within a given margin of the HR-CTV. The dosimetric parameters (D2cc, D1cc, D0.1cc) reported by Oncentra were recorded for the original bowel volume, as well as the limited bowel volumes produced to enable comparison. Results: A total of 10 plans were contoured and assessed, with comparison of the dosimetric parameters performed for the limited bowel volumes. A summary of the results is given in the table. The mean doses for the fully contoured bowel were 3.99Gy, 4.39Gy and 5.37Gy for the D2cc, D1cc and D0.1cc respectively . When the bowel was limited to within 1.5cm or less of the HR-CTV there was at least one contour which did not give sufficient volume to produce complete dose statistics. When considering contouring within a 2.0cm margin of the HR-CTV the mean change in the D0.1cc was less than 0.1Gy (with D2cc and D1cc being less than 0.05Gy). The reduction in volume contoured however was large, with a reduction of around 65% in volume when restricting contouring to within 2.0cm of the HR-CTV.