Colin Hornby

A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer

BackgroundTo compare 3 Dimensional Conformal radiotherapy (3D-CRT) with Intensity Modulated Radiotherapy (IMRT) with Volumetric-Modulated Arc Therapy (VMAT) for bladder cancer.MethodsRadiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB) of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated.ResultsMean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI) index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI) index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250–293) for 3D-CRT; 824 (range 641–1083) for IMRT; and 403 (range 333–489) for VMAT (P < 0.05). Average treatment delivery time were 2:25min (range 2:01–3:09) for 3D-CRT; 4:39 (range 3:41–6:40) for IMRT; and 1:14 (range 1:13–1:14) for VMAT. In selected patients, the SIB did not result in a higher dose to small bowel or rectum.ConclusionsVMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours.

Does inverse-planned intensity-modulated radiation therapy have a role in the treatment of patients with left-sided breast cancer?

Introduction: The purpose of the study was to determine if multi‐field inverse‐planned intensity‐modulated radiation therapy (IMRT) improves on the sparing of organs at risk (heart, lungs and contralateral breast) when compared with field‐in‐field forward‐planned RT (FiF).

A decision model to estimate the cost-effectiveness of intensity modulated radiation therapy (IMRT) compared to three dimensional conformal radiation therapy (3DCRT) in patients receiving radiotherapy to the prostate bed

BACKGROUND Intensity modulated radiation therapy (IMRT) is a radiation therapy technology that facilitates the delivery of an improved dose distribution with less dose to surrounding critical structures. This study estimates the longer term effectiveness and cost-effectiveness of IMRT in patients post radical prostatectomy. METHODS A Markov decision model was developed to calculate the incremental quality adjusted life years (QALYs) and costs of IMRT compared with three dimensional conformal radiation therapy (3DCRT). Costs were estimated from the perspective of the Australian health care system. RESULTS IMRT was both more effective and less costly than 3DCRT over 20 years, with an additional 20 QALYs gained and over

Reducing posttreatment dysphagia: Support for the relationship between radiation dose to the pharyngeal constrictors and swallowing outcomes

1.1 million saved per 1000 patients treated. This result was robust to plausible levels of uncertainty. CONCLUSIONS IMRT was estimated to have a modest long term advantage over 3DCRT in terms of both improved effectiveness and reduced cost. This result was reliant on clinical judgement and interpretation of the existing literature, but provides quantitative guidance on the cost effectiveness of IMRT whilst long term trial evidence is awaited.

Novel 3D conformal technique for treatment of choroidal melanoma with external beam photon radiotherapy.

PURPOSE This study used prospective swallowing data to establish the following: (1) whether doses to the pharyngeal constrictor muscles (PCMs) were significantly associated with swallowing outcomes; and (2) a mean dose constraint to aim for in intensity modulated radiation therapy planning. METHODS AND MATERIALS The PCMs were contoured and radiation dose data obtained for 55 patients with head and neck cancer. Associations between radiation dose and percentage of pharyngeal residue, penetration-aspiration and activity limitation measured at 6 months posttreatment were analyzed. Pretreatment swallowing function, tumor site, T classification, and chemotherapy were accounted for in multivariate analyses. RESULTS On multivariate analysis, the percentage of pharyngeal residue was statistically significantly associated with the mean dose to the superior PCM (95% confidence interval [CI], 0.15-1.66; P = .02). Penetration-aspiration was associated with the mean dose to the superior, middle, and inferior PCMs (95% CI, 1.02-1.27; P = .003; 95% CI, 1.02-1.23; P = .003; 95% CI, 1.04-1.21; P = .003, respectively) and the mean dose to the total PCM (95% CI, 1.05-1.31; P = .001). Activity limitation was also associated with the mean dose to the superior, middle, and inferior PCMs (95% CI, 1.01-1.20; P = .02; 95% CI, 1.00-1.15; P =.04; 95% CI, 1.01-1.15; P = .02, respectively) and the mean dose to the total PCM (95% CI, 1.02-1.23; P = .01). On univariate analysis, all 3 swallowing measures were statistically significantly worse for patients who received a biologically equivalent mean dose of >60 Gy to the PCMs. This remained significant on multivariate analysis for both penetration-aspiration and activity limitation (95% CI, 2.05-58.2, P = .004 and 95% CI, 1.14-27.7, P = .03, respectively). CONCLUSIONS The radiation dose to the PCMs is significantly associated with swallowing dysfunction. Limiting the mean PCM dose to less than 60 Gy results in better swallowing outcomes.

Optimising the dosimetric quality and efficiency of post-prostatectomy radiotherapy: a planning study comparing the performance of volumetric-modulated arc therapy (VMAT) with an optimised seven-field intensity-modulated radiotherapy (IMRT) technique.

To report a 3D conformal radiotherapy (3D‐CRT) technique that utilises a specific eye immobilisation and treatment set‐up method as an alternative to stereotactic radiotherapy (SRT), for treatment of juxtapapillary choroidal melanoma (CM) and report early treatment outcomes of this technique.

Guidelines for timely initiation of chemotherapy: a proposed framework for access to medical oncology and haematology cancer clinics and chemotherapy services.

Purpose: The purpose of this study was to compare and evaluate radiotherapy treatment plans using volumetric modulated arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) for post‐prostatectomy radiotherapy.

Testing the Assessment of New Radiation Oncology Technology and Treatments framework using the evaluation of post-prostatectomy radiotherapy techniques.

These guidelines, informed by the best available evidence and consensus expert opinion, provide a framework to guide the timely initiation of chemotherapy for treating cancer. They sit at the intersection of patient experience, state‐of‐the‐art disease management and rational efficient service provision for these patients at a system level. Internationally, cancer waiting times are routinely measured and publicly reported. In Australia, there are existing policies and guidelines relating to the timeliness of cancer care for surgery and radiation therapy; however, until now, equivalent guidance for chemotherapy was lacking. Timeliness of care should be informed, where available, by evidence for improved patient outcomes. Independent of this, it should be recognised that shorter waiting periods are likely to reduce patient anxiety. While these guidelines were developed as part of a proposed framework for consideration by the Victorian Department of Health, they are clinically relevant to national and international cancer services. They are intended to be used by clinical and administrative staff within cancer services. Adoption of these guidelines, which are for the timely triage, review and treatment of cancer patients receiving systemic chemotherapy, aims to ensure that patients receive care within a timeframe that will maximise health outcomes, and that access to care is consistent and equitable across cancer services. Local monitoring of performance against this guideline will enable cancer service providers to manage proactively future service demand.

Quality assurance in a Radiation Oncology Unit: The Chart Round experience

We tested the ability of the Assessment of New Radiation Oncology Technology and Treatments framework to determine the clinical efficacy and safety of intensity‐modulated radiation therapy (IMRT) compared with 3‐dimensional radiation therapy (3DCRT) for post‐prostatectomy radiation therapy (PPRT) to support its timely health economic evaluation.