Deidre L. Batchelar

Assessing the role of volumetric modulated arc therapy (VMAT) relative to IMRT and helical tomotherapy in the management of localized, locally advanced, and post-operative prostate cancer.

PURPOSEnTo quantify differences in treatment delivery efficiency and dosimetry between step-and-shoot intensity-modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), and helical tomotherapy (HT) for prostate treatment.nnnMETHODS AND MATERIALSnTwenty-five prostate cancer patients were selected retrospectively for this planning study. Treatment plans were generated for: prostate alone (n = 5), prostate + seminal vesicles (n = 5), prostate + seminal vesicles + pelvic lymph nodes (n = 5), prostate bed (n = 5), and prostate bed + pelvic lymph nodes (n = 5). Target coverage, dose homogeneity, integral dose, monitor units (MU), and sparing of organs at risk (OAR) were compared across techniques. Time required to deliver each plan was measured.nnnRESULTSnThe dosimetric quality of IMRT, VMAT, and HT plans were comparable for target coverage (planning target volume V95%, clinical target volume V100% all >98.7%) and sparing of organs at risk (OAR) for all treatment groups. Although HT resulted in a slightly higher integral dose and mean doses to the OAR, it yielded a lower maximum dose to all OAR examined. VMAT resulted in reductions in treatment times over IMRT (mean = 75%) and HT (mean = 70%). VMAT required 15-38% fewer monitor units than IMRT over all treatment volumes, with the reduction per fraction ranging from 100-423 MU from the smallest to largest volumes.nnnCONCLUSIONSnVMAT improves efficiency of delivery for equivalent dosimetric quality as IMRT and HT across various prostate cancer treatment volumes in the intact and postoperative settings.

Health-Related Quality of Life After Single-Fraction High-Dose-Rate Brachytherapy and Hypofractionated External Beam Radiotherapy for Prostate Cancer

PURPOSEnTo investigate the change in health-related quality of life for men after high-dose-rate brachytherapy and external beam radiotherapy for prostate cancer and the factors associated with this change.nnnMETHODS AND MATERIALSnEligible patients had clinically localized intermediate-risk prostate cancer. The patients received high-dose-rate brachytherapy as a single 15-Gy implant, followed by external beam radiotherapy to 37.5 Gy in 15 fractions. The patients were monitored prospectively for toxicity (Common Terminology Criteria for Adverse Events, version 3.0) and health-related quality of life (Expanded Prostate Cancer Index Composite [EPIC]). The proportion of patients developing a clinically significant difference in the EPIC domain score (minimally important difference of >0.5 standard deviation) was determined and correlated with the baseline clinical and dosimetric factors. The study accrued 125 patients, with a median follow-up of 24 months.nnnRESULTSnBy 24 months, 23% had Grade 2 urinary toxicity and only 5% had Grade 2 bowel toxicity, with no Grade 3 toxicity. The proportion of patients reporting a significant decrease in EPIC urinary, bowel, sexual, and hormonal domain scores was 53%, 51%, 45%, and 40% at 12 months and 57%, 65%, 51%, and 30% at 24 months, respectively. The proportion with a >1 standard deviation decrease in the EPIC urinary, bowel, sexual, and hormonal domain scores was 38%, 36%, 24%, and 20% at 12 months and 46%, 48%, 19%, and 8% at 24 months, respectively. On multivariate analysis, the dose to 10% of the urethra was associated with a decreasing EPIC urinary domain score (p = .0089) and, less strongly (p = .0312) with a decreasing hormonal domain score. No association was found between the prostate volume, bladder dose, or high-dose volume and urinary health-related quality of life. A high baseline International Index of Erectile Function score was associated (p = .0019) with a decreasing sexual domain score. The optimal maximal dose to 10% of the urethra cutpoint for urinary health-related quality of life was 120% of the prescription dose.nnnCONCLUSIONnEPIC was a more sensitive tool for detecting the effects on function and bother than were the generic toxicity scales. The urethral dose had the strongest association with a deteriorating urinary quality of life.

Imaging Technologies for High Dose Rate Brachytherapy for Cervical Cancer: A Systematic Review

The aim of this overview was to assess the utility of various imaging technologies (fluoroscopy, ultrasound, computed tomography, magnetic resonance imaging and positron emission tomography) for the treatment planning of high dose rate brachytherapy for cervical cancer. Reviews and primary studies comparing different imaging technologies used during high dose rate brachytherapy for cervical cancer and published from 1988 to 2008 were sought by searching MEDLINE and EMBASE databases, the Cochrane Library, personal files and reference lists of identified studies, and by contacting experts. Study selection, study quality assessment and data extraction were carried out in duplicate. Twelve studies met the inclusion criteria. No systematic reviews or randomised controlled studies (RCTs) were located. The validity assessment revealed that the quality of the existing studies is very variable. This is the first systematic review in the area of imaging technologies for cervix brachytherapy. No RCTs have been located and it is possible that an RCT is not the optimal methodology to assess imaging technologies. However, in this area there is a need for more prospective studies and for studies that consider the expertise of the operators in their design. The studies found supported the use of three-dimensional imaging as opposed to the traditional two-dimensional imaging. However, apart from the effectiveness of visualising tumours and surrounding tissues, the utility of imaging technologies in clinical practice is determined by other contextual factors, such as their availability, accessibility and ease of use.

Delivery of Brachytherapy for Cervical Cancer: Organisational and Technical Advice to Facilitate High-quality Care

AIMSnBrachytherapy is a standard therapy for cervical cancer; it allows for the delivery of a high dose of radiation to the tumour while sparing the surrounding healthy tissues. With this document, the Brachytherapy Cervical Cancer Expert Working Group (BCCEWG) aimed to provide advice on organisational and technical aspects of the delivery of brachytherapy services in Ontario, Canada.nnnMATERIALS AND METHODSnWe sought technical documents, practice guidelines and standards through an environmental scan of internet resources, an iterative search of the literature on MEDLINE and EMBASE, and a search of reference lists of included documents.nnnRESULTSnWe identified 20 guidance documents authored by 10 organisations; 11 documents were identified through the environmental scan, five through the literature search and four from reference lists. The recommendations included in this document were developed by the BCCEWG through the selection and review of the evidence and informal consensus.nnnCONCLUSIONSnThese organisational recommendations aim to set the stage for high-quality delivery of brachytherapy for cervical cancer services in the province of Ontario, Canada. They address the characteristics of the practice setting, including facilities, equipment, delivery suite, imaging technologies, treatment planning and dosimetry; the practice team, including team members, roles, training, team caseload/volumes and qualifications; and the quality assurance domain, including documentation, audit, safety and quality control.

Intraoperative ultrasound-based planning can effectively replace postoperative CT-based planning for high-dose-rate brachytherapy for prostate cancer.

PURPOSEnUltrasound (US)-based planning for high-dose-rate brachytherapy allows prostate patients to be implanted, imaged, planned, and treated without changing position. This is advantageous with respect to accuracy and efficiency of treatment but is only valuable if plan quality relative to CT is maintained. This study evaluates any dosimetric impact of changing from CT- to US-based planning.nnnMETHODS AND MATERIALSnThirty patients each were randomly selected from CT-planned and US-planned cohorts. All received single fraction high-dose-rate brachytherapy (15xa0Gy) followed by 37.5xa0Gy in 15 fractions external beam radiation therapy. Prostate V90, V100, V150, V200, D90, and the dose homogeneity index were compared. For the rectum, Dmax, D0.5cc, D1cc, V10, V50, and V80 were examined. For the urethra, only Dmax and D10 were considered.nnnRESULTSnUS plans had smaller 200% hot spots, although the dose homogeneity index for both was 0.7xa0±xa00.1. On average, plans using either modality satisfied planning goals. Although several parameters were significantly different between the two modalities (p < 0.05), the absolute differences were small. Of greatest, clinical relevance was the difference in frequency with which upper dose goals were exceeded. The prostate V200 goal was exceeded in 53% of CT-planned cases, but only 20% of those planned with US. The urethral D10 goal was never exceeded using US but was exceeded in 13% of CT cases.nnnCONCLUSIONSnUS planning results in plans that, clinically, are dosimetrically equivalent to CT-based planning. Upper dosimetric goals are, however, exceeded less often with US than with CT.

Sci—Sat AM(2): Brachy — 03: Post‐Operative CT or Intra‐Operative US for Planning Single Fraction Prostate HDR Brachytherapy? The Odette Experience

There is a growing body of evidence demonstrating that using HDR brachytherapy as a local boost for patients with intermediate‐risk prostate cancer provides a survival advantage over EBRT alone. In September 2009 we transitioned from using post‐operative CT‐based planning to intraoperative US‐based planning for our single fraction technique. The dosimetric impact of this change is assessed in this retrospective analysis of 23 patients from each of our CT and US cohorts. We also consider the impact of this change on our resource allocations and patient throughput. Generally, US‐based planning can be considered dosimetrically equivalent to CT‐based planning. It was found to produce plans that exceed dosimetric goals less often than CT. US planning offers several other advantages. Importantly, the patient remains in the same position throughout the procedure, thus the needles remain in the intended position. This eliminates uncertainty introduced by motion between planning and delivery and makes needle position QA straightforward. Improved needle positioning also results decreased time required to achieve a clinically acceptable plan. Intraoperative planning has proved to be an efficient mode of delivering HDR brachytherapy. Although each case occupies the brachytherapy suite for up to 2.5hr, elimination of moving the patient to CT, improved contouring tools, and the reduction in both planning and pre‐treatment QA time have made this procedure much quicker for the whole brachytherapy team. Moving to US‐based planning has permitted us to more than double the number of patients we can treat in a year with HDR brachytherapy for prostate.