AimsQuality assurance in radiotherapy (QART) is essential to ensure the scientific integrity of a clinical trial. This paper reports the findings of the retrospective QART assessment for all centres that participated in PORTEC-3; a randomised controlled trial that compared pelvic radiotherapy with concurrent chemoradiotherapy to the pelvis followed by adjuvant chemotherapy. The trial showed an overall survival benefit for the addition of the chemotherapy in the management of women with high-risk endometrial cancer.Materials and methodsClinicians were invited to upload a randomly selected case/s treated at each of the participating sites. Panel reviewers analysed the contours to certify that the target volumes and organ at risk structures were contoured according to guidelines. The results were categorised into acceptable, minor variation, major variation or unevaluable. The radiotherapy plans were dosimetrically evaluated using the well-established Trans-Tasman Radiation Oncology Group (TROG) protocol.ResultsBetween August 2010 and January 2018, data from 146 patients of 686 consecutively treated patients were retrospectively reviewed. All 16 Australia and New Zealand and 71 of 77 international centres uploaded data for evaluation. In total, 3514 dosimetric and contour variables were reviewed. Of these, 3136 variables were deemed acceptable (89.2%), with 335 minor (9.6%) and 43 major variations (1.2%). Major contour variations included the clinical target volume vaginal vault, clinical target volume parametria and differential planning target volume vault expansion.ConclusionThe results of the QART assessment confirmed high uniformity and low rates of both minor and major deviations in contouring and dosimetry in all sites. This supports the safe introduction of the PORTEC-3 treatment protocol into routine clinical practice.

Large multicentre radiotherapy trials incorporating assessment of multiple outcomes at multiple timepoints can generate extensive datasets. We have investigated graphical techniques for presentation of this data and the associated underlying dose-volume response information, necessary for guiding statistical analyses and translating outcomes to future patient treatments. A relational database was used to archive reviewed plan data for patients accrued to the TROG 03.04 RADAR trial. Viewing software was used to clean and enhance the data. Scripts were developed to export arbitrary dose-histogram data which was combined with clinical toxicity data with a median follow-up of 72 months. Graphical representations of dose-volume response developed include prevalence atlasing, univariate logistic regression and dose-volume-point odds ratios, and continuous cut-point derivation via ROC analysis. These representations indicate variable association of toxicities across structures and time-points.

Dose constraints based on histograms provide a convenient and widely-used method for informing and guiding radiotherapy treatment planning. Methods of derivation of such constraints are often poorly described. Two non-parametric methods for derivation of constraints are described and investigated in the context of determination of dose-specific cut-points-values of the free parameter (e.g., percentage volume of the irradiated organ) which best reflect resulting changes in complication incidence. A method based on receiver operating characteristic (ROC) analysis and one based on a maximally-selected standardized rank sum are described and compared using rectal toxicity data from a prostate radiotherapy trial. Multiple test corrections are applied using a free step-down resampling algorithm, which accounts for the large number of tests undertaken to search for optimal cut-points and the inherent correlation between dose-histogram points. Both methods provide consistent significant cut-point values, with the rank sum method displaying some sensitivity to the underlying data. The ROC method is simple to implement and can utilize a complication atlas, though an advantage of the rank sum method is the ability to incorporate all complication grades without the need for grade dichotomization.

Purpose: To determine dosimetric predictors of late rectal toxicity after prostate radiotherapy, differentiating between dose to rectum and anal canal. Methods: Clinical and 3D dosimetric data for 738 patients were prospectively collected in a clinical trial (TROG 03.04 “RADAR”) of variable‐duration hormone therapy with conformal radiotherapy using rectal DVH constraints of V65<40%, V70<30%, V75<5%. Dose‐volume histograms were generated for whole anorectum, anal canal, rectum and matched to longitudinal toxicity (measured 6‐monthly). Outcome measures were: bleeding, urgency/tenesmus (grade 1+, 2+, 3), pooled Common Toxicity Criteria version 2 proctitis (grade 1+, 2+), incontinence, bowel bother, diarrhea, and anorectal pain. Both prevalence (at 30 months post radiotherapy) and actuarial incidence (time‐to‐failure) endpoints were analyzed. Rectal mean dose and V5–V70 were used as factors in multivariate and univariate logistic regression (prevalence) and Cox proportional hazards (incidence) analyses. Results: Median follow‐up was 6.5 years post‐treatment. Multivariate models produced erratic effect estimates due to multicollinearity arising from constrained DVH shape as mandated by the trial protocol. Univariate analysis identified that pain, pooled proctitis, incontinence were predicted most by anal canal dose. Bleeding and diarrhea were not subvolume dependent. Bowel bother was not associated with any factor. Urgency/tenesmus association with subvolume depended on the outcome grade used. Conclusion: Doses to different subvolumes of the rectum are responsible for different types of toxicity. Different grades of the same toxicity are predicted by different subvolumes and DVH points. For datasets planned with dose constraints, multicollinearity of DVH points limits the usefulness of multivariate analysis. Further work will estimate DVH constraints to limit toxicity, and Lyman model parameters from the same data. Funding: National Health and Medical Research Council (Australian Government), Hunter Prostate Cancer Alliance, Trans‐Tasman Radiation Oncology Group. Conflicts of interest: none declared

Skin dose is an unavoidable consequence of breast radiotherapy. It is sometimes tempting to reduce the variability of the external contour by use immobilization material. Increased dose in skin folds can also be reduced with the use of cast material. These dosimetry experiments aim to determine using an anthropomorphic phantom surrogate what changes in surface dose can be attributed to the use of an orbit immobilization cast when used to secure the breasts for reproducibility in radiotherapy. The question of whether to accept a small increase in skin dose over a large area from use of an immobilization cast, or a large skin dose to a small area resulting from a skin fold, is central to this paper. This paper however, only attempts to provide data on the increase in dose from the presence of the cast, and not data relating to the change in breast contour. Skin dose is measured using EBT film dosimetry and MOSkins on an anthropomorphic phantom to measure dose at a range of water equivalent depths representative of the different skin layers. EBT film is used as an integrating dosimeter, while the MOSkins are used to obtain real-time dosimetry to isolate dose from the individual intensity modulated radiation therapy (IMRT) segments. Results show a general increase in dose to the skin in the presence of the orbit immobilization cast. A significant increase was noted particularly in regions where the beam is highly tangential to the skin surface and in the build-up region. Superior to the breast, the in-field dose increase was found to be on average 34.5%, 25% across the apex, and 17.6% inferior to the breast. The increase in skin dose from using cast material on breast patients for immobilization has been examined. It is hoped quantifying the exact skin dose by measurement may aid in quantifying dose effect relationships in the future.

Summary Dose escalation in radiation therapy has led to increased control rates with some clinical trial evidence that rectal toxicity may be reduced when using intensity‐modulated radiotherapy (IMRT) over 3D conformal radiotherapy (3DCRT) for dose‐escalated prostate radiotherapy. However, IMRT for prostate patients is not yet standard in many Australian radiation oncology centres. This study investigates dosimetric changes that can be observed between IMRT and 3DCRT in prostate radiotherapy. Fifteen patients were selected for analysis. Two target definitions were investigated – prostate‐only and prostate plus seminal vesicles (p + SVs). A five‐field 3DCRT and seven‐field IMRT plan were created for each patient and target definition. The planning target volume coverage was matched for both plans. Doses to the rectum, bladder and femoral heads were compared using dose volume histograms. The rectal normal tissue complication probabilities (NTCPs) were calculated and compared for the 3DCRT and IMRT plans. The delivery efficiency was investigated. The IMRT plans resulted in reductions in the V25, V50, V60, V70 and V75 Gy values for both the prostate‐only and p + SVs targets. Rectal NTCP was reduced with IMRT for three different sets of model parameters. The reductions in rectal dose and NTCP were much larger for the p + SVs target. Delivery of IMRT plans was less efficient than for 3DCRT plans. IMRT resulted in superior plans based on dosimetric and biological endpoints. The dosimetric gains with IMRT were greater for the more complex p + SVs target. The gains made came at the cost of decreased delivery efficiency.

Introduction: Treatment plan evaluation requires knowledge of the effect of the plan, not only on the intended target, but also the surrounding normal tissues that are unavoidably irradiated. Recent literature has provided estimations of tolerance doses and proposed dose-volume constraints for many of the organs at risk. However, very few of these recommendations have been independently validated. This study details how constraints proposed for the rectum were tested using data from the RT01 randomised prostate radiotherapy trial. Method: An independent validation of the rectal dose-volume constraints used in the CHHiP trial and proposed recently by Fiorino et al. was performed. The constraints were applied retrospectively to the treatment plans collected from the RT01 trial. Odds ratios (OR) were calculated to compare the reported incidence of specific late rectal toxicity end points in the group of patients whose treatment plan met a specified dose-volume constraint compared to the group of patients who failed that constraint. Results: Statistically significant ORs were observed for every constraint tested (except 75 Gy) for at least one clinical end point. For the CHHiP constraints between 60 and 70 Gy, the ORs calculated for rectal bleeding (RMH score defined in protocol) exceeded 2.5 (P!0.02). Similarly the ORs for CHHiP constraints between 30 and 65 Gy exceeded 2.4 (P!0.021) for urgency (UCLA PCI). The Fiorino constraints between 40 and 60 Gy resulted in ORs O2 (P!0.02) for loose stools (UCLA PCI) Conclusion: Implementing rectal dose-volume constraints from 30 Gy up to the prescription dose will result in a decrease in the incidence of late rectal toxicity. Constraints for doses as low as 30 Gy were statistically significant, further challenging the concept that the rectum is a serial structure where the maximum dose to the organ is the only consideration.

Aims: To quantify the inter-fractional variation in bladder volume and position during a course of bladder radiotherapy, and to assess the feasibility of reducing the planning target volume (PTV) internal margin using an empty bladder protocol.Materials and methods: Weekly computed tomography scans were taken immediately after micturition on 15 patients undergoing radical radiotherapy for bladder cancer. Bladder volume and positional variation were compared by co-registration of the serial computed tomography scans with the initial planning scan and a single 'full' scan at the onset of treatment for each patient. A PTV was generated on the initial planning scan using both our departmental standard of 1.5 cm and a reduced 1 cm isotropic internal margin around the target (whole bladder) and the relative proportion of the bladder breaching the PTV using both margins compared.Results: The mean post void residual volume from the planning scan was 112 cm(3) (standard deviation 42 cm(3)). The mean weekly variation in bladder volume relative to the planning volume was 0-12% (standard deviation 20-34%) with no observable trends over time. No statistically significant differences were seen in the proportion of bladder breaching the 1.5 and 1 cm internal margin (P = 0.18). Regression analysis showed that it is possible to ensure complete coverage of the bladder with a 1 cm margin, providing the volume did not exceed over 50% of the initial planning scan volume.Conclusion: Using an empty bladder protocol and where on-line imaging is available it is feasible to reduce the internal margin of the PTV from 1.5 to 1cm, providing the volumes do not exceed > 50% of the planning scan volume. Mangar, S. A. et al. (2008). Clinical Oncology 20, 698-704 (c) 2008 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Purpose: To find appropriate parameter values for the Lyman-Kutcher-Burman (LKB), Normal Tissue Complication Probability (NTCP) model for modern, clinically relevant late rectal side effects experienced after prostate radiotherapy. Method and Materials: Rectal dose-volume histograms and detailed long-term follow-up data from 178 patients from the MRC RT01 multicentre randomized controlled trial of conformal prostate radiotherapy were analysed. Endpoints chosen to represent late toxicities reported in modern practice were rectal bleeding and proctitis recorded by the clinician and loose stools and urgency recorded by the patient. The various grading schemes used in the trial were standardized in terms of moderate/severe toxicity. Patients with pre-treatment symptoms were excluded from the analysis. Optimal LKB parameter values for TD50(1), m and n were found using the maximum likelihood estimation of log-likelihood. 95% confidence intervals were calculated using the profile-likelihood method. Results: The maximum-likelihood estimation yielded values of TD50(1)=67.50 (CI 65.49–69.96), m=0.15 (CI 0.11–0.21), n=0.10 (CI 0.07–0.14) for proctitis; TD50(1)=67.75 (CI 63.64–72.89), m=0.25 (CI 0.20–0.34), n=0.28 (CI 0.18–0.45) for rectal bleeding; TD50(1)=73.50 (CI 64.29–86.73), m=0.38 (CI 0.30–0.49), n=1.00 (CI 0.37 — outside range calculated) for loose stools and TD50(1)=67.00 (CI 61.89–73.60), m=0.30 (CI 0.22–0.44), n=0.30 (CI 0.17–0.56) for rectal urgency. Conclusion: The NTCP parameters obtained for four clinically relevant rectal side effects were significantly different from each other. The results for proctitis provide the best comparison with the original Emami data, the values for m and n were in good agreement whilst TD50(1) was significantly lower, perhaps reflecting the reduction in severity of complication. Values of n implying both serial and parallel volume effect were observed. These variations highlight the complexity of the dose-volume response of the rectum and indicate that the NTCP model should be used with caution as a clinical tool.

You have accessJournal of UrologyVideo Session 3, Monday, May 21, 2007 10:00 am - 12:00 pm1 Apr 2007V872: The Importance of Intravesical Prostate Protrusion in Predicting Bladder Outlet Obstruction in Patients with Good Urinary Flow Henry Ho, KokBin Lim, K. Foo, and M. Wong Henry HoHenry Ho More articles by this author , KokBin LimKokBin Lim More articles by this author , K. FooK. Foo More articles by this author , and M. WongM. Wong More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(18)32163-3AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "V872: The Importance of Intravesical Prostate Protrusion in Predicting Bladder Outlet Obstruction in Patients with Good Urinary Flow." The Journal of Urology, 177(4S), p. 290 © 2016 by American Urological AssociationFiguresReferencesRelatedDetails Volume 177Issue 4SApril 2007Page: 290 Advertisement Copyright & Permissions© 2016 by American Urological AssociationMetricsAuthor Information Henry Ho More articles by this author KokBin Lim More articles by this author K. Foo More articles by this author M. Wong More articles by this author Expand All Advertisement Loading ...

To investigate the role of intravesical prostatic protrusion (IPP) in predicting of bladder outlet obstruction (BOO) due to benign prostatic enlargement (BPE) in patients with good urinary flow.

Intravesical prostatic protrusion (IPP) had been shown to correlate significantly with benign prostatic obstruction on pressure flow study. Prostate volume (PV) has also been shown to be important in the progression of BPE. In real life practice, any particular male patient with lower urinary tract symptoms would have a combination of PV and IPP. Can these be classified to predict bladder outlet obstruction in real life practice?

Aims: The radiation dose used to treat bladder cancer is limited by the risk of inducing severe late bladder toxicity. Retrospective data suggest that radiation tolerance is greater for partial rather than whole bladder irradiation. Limiting the high-dose region to a section of the bladder may reduce toxicity, opening the way for dose escalation. The aims of this study were to establish the efficacy and compare the late toxicity between (1) a two-phase technique limiting the high-dose area and (2) a conventional single-phase radiotherapy to the whole bladder.Materials and methods: A cohort study was undertaken of 229 patients with invasive bladder cancer treated with computed tomography-planned radical radiotherapy at the Royal Marsden Hospital from 1984 to 1998. In total, 154 patients received a single-phase treatment to the whole bladder with a 2 cm margin. Seventy-five patients with solitary, well-localised tumours were selected for treatment using a two-phase technique. The first phase (12 Gy) aimed to treat the tumour with a 2 cm margin. A second phase treated the whole bladder with 52 Gy. One hundred and forty-one patients were planned to receive a dose of 60-64 Gy/30-32 fractions over 6-6.5 weeks, whereas 88 patients received an accelerated regime. Data on late bladder and bowel toxicity (using Radiation Therapy Oncology Group criteria) were collected prospectively at the annual review.Results: At the 5-year follow-up there was no difference in overall survival (hazard ratio = 0.91, 95% confidence interval 0.64-1.3) or failure-free survival (hazard ratio = 1.02, 95% confidence interval 0.73-1.43) between the two techniques. The two-phase reduced volume treatment was less toxic, with a 19% absolute reduction in overall grade 3-4 late toxicity (P = 0.02). These differences were more marked for bladder toxicity compared with bowel toxicity.Conclusions: The two-phase reduced volume technique was associated with less bladder and bowel toxicity than conventional whole bladder radiotherapy without evidence of impaired survival.