Variations in anatomical delineation, principally due to a combination of inter-observer contributions and image-specificity, remain one of the most significant impediments to geometrically-accurate radiotherapy. Quantification of spatial variability of the delineated contours comprising a structure can be made with a variety of metrics, and the availability of software tools to apply such metrics to data collected during inter-observer or repeat-imaging studies would allow their validation. A suite of such tools have been developed which use an Extensible Markup Language format for the exchange of delineated 3D structures with radiotherapy planning or review systems. These tools provide basic operations for manipulating and operating on individual structures and related structure sets, and for deriving statistics on spatial variations of contours that can be mapped onto the surface of a reference structure. Use of these tools on a sample dataset is demonstrated together with import and display of results in the SWAN treatment plan review system.
This study examined the variation of dose-volume histogram (DVH) data sourced from multiple radiotherapy treatment planning systems (TPSs). Treatment plan exports were obtained from 33 Australian and New Zealand centres during a dosimetry study. Plan information, including DVH data, was exported from the TPS at each centre and reviewed in a digital review system (SWAN). The review system was then used to produce an independent calculation of DVH information for each delineated structure. The relationships between DVHs extracted from each TPS and independently calculated were examined, particularly in terms of the influence of CT scan slice and pixel widths, the resolution of dose calculation grids and the TPS manufacturer. Calculation of total volume and DVH data was consistent between SWAN and each TPS, with the small discrepancies found tending to increase with decreasing structure size. This was significantly influenced by the TPS model used to derive the data. For target structures covered with relatively uniform dose distributions, there was a significant difference between the minimum dose in each TPS-exported DVH and that calculated independently.
Health-related quality of life (HQOL) research is a means of broadening the assessment of treatment effects. This longitudinal study investigated the dynamic change to quality of life (QOL) and testosterone dependant physiology in men commencing an intermittent maximal androgen blockade program (IMAB). Two hundred and fifty men were accrued to the multi-centre study of IMAB (Flutamide 250mg TDS, Leuprolide 22.5mg depot) ceasing treatment after 9 months if PSA <4ng/ml, and restarting when PSA >20ng/ml. QOL was assessed every 3 months for 30 months using the EORTC QLQ-C30 and EORTC QLQ-PR25 module. Data completion for the whole study was 90%. At baseline, our cohort was less symptomatic and had better function than the EORTC reference cohort, which may be related to a shift in clinical practice with time. Testosterone suppression (AS) lead to a significant reduction in global HQOL and deterioration in most function and symptom scales. During the off period, there was a trend of progressive improvement in HQOL that paralleled testosterone recovery but was slower than the rate of deterioration during the treatment phase. Maximum recovery of HQOL occurred most frequently by months 9–12. Testosterone recovery was slower and less complete in older men, and lead to concomitant poorer HOQL recovery. Whilst the magnitude of mean change to scale scores was small, there was a consistent and simultaneous deterioration during maximal androgen blockade (MAB) and improvement during androgen recovery. Older men are more likely to show an impaired testosterone recovery, and this was paralleled by a slower HQOL recovery. Newer methods of analysis to describe results in a way that has meaning to the individual patient are warranted.