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Purpose: Tumor and target volume manual delineation remains a challenging task in head and neck cancer radiation therapy. The purpose of this study was to conduct a multi-institutional evaluation of manual delineations of gross tumor volume (GTV), high-risk clinical target volume (CTV), parotids, and submandibular glands on treatment simulation magnetic resonance scans of patients with oropharyngeal cancer., Methods and Materials: We retrospectively collected pretreatment T1-weighted, T1-weighted with gadolinium contrast, and T2-weighted magnetic resonance imaging scans for 4 patients with oropharyngeal cancer under an institution review board-approved protocol. We provided the scans to 26 radiation oncologists from 7 international cancer centers that participated in this delineation study. We also provide the patients' clinical history and physical examination findings, along with a medical photographic image and radiologic results. We used both the Simultaneous Truth and Performance Level Estimation algorithm and pair-wise comparisons of the contours, using overlap/distance metrics. Lastly, to assess experience and CTV delineation institutional practices, we had participants complete a brief questionnaire., Results: Large variability was measured between observers' delineations for GTVs and CTVs. The mean Dice similarity coefficient values across all physicians' delineations for GTVp, GTVn, CTVp, and CTVn were 0.77, 0.67, 0.77, and 0.69, respectively, for Simultaneous Truth and Performance Level Estimation algorithm comparison, and 0.67, 0.60, 0.67, and 0.58, respectively, for pair-wise analysis. Normal tissue contours were defined more consistently when considering overlap/distance metrics. The median radiation oncology clinical experience was 7 years. The median experience delineating on magnetic resonance imaging was 3.5 years. The GTV-to-CTV margin used was 10 mm for 6 of 7 participant institutions. One institution used 8 mm, and 3 participants (from 3 different institutions) used a margin of 5 mm., Conclusions: The data from this study suggests that appropriate guidelines, contouring quality assurance sessions, and training are still needed for the adoption of magnetic resonance-based treatment planning for head and neck cancers. Such efforts should play a critical role in reducing delineation variation and ensure standardization of target design across clinical practices., (Copyright © 2022. Published by Elsevier Inc.)

Purpose: In a randomized focal dose escalation radiation therapy trial for prostate cancer (FLAME), up to 95 Gy was prescribed to the tumor in the dose-escalated arm, with 77 Gy to the entire prostate in both arms. As dose constraints to organs at risk had priority over dose escalation and suboptimal planning could occur, we investigated how well the dose to the tumor was boosted. We developed an anatomy-based prediction model to identify plans with suboptimal tumor dose and performed replanning to validate our model., Methods and Materials: We derived dose-volume parameters from planned dose distributions of 539 FLAME trial patients in 4 institutions and compared them between both arms. In the dose-escalated arm, we determined overlap volume histograms and derived features representing patient anatomy. We predicted tumor D98% with a linear regression on anatomic features and performed replanning on 21 plans., Results: In the dose-escalated arm, the median tumor D50% and D98% were 93.0 and 84.7 Gy, and 99% of the tumors had a dose escalation greater than 82.4 Gy (107% of 77 Gy). In both arms organs at risk constraints were met. Five out of 73 anatomic features were found to be predictive for tumor D98%. Median predicted tumor D98% was 4.4 Gy higher than planned D98%. Upon replanning, median tumor D98% increased by 3.0 Gy. A strong correlation between predicted increase in D98% and realized increase upon replanning was found (ρ = 0.86)., Conclusions: Focal dose escalation in prostate cancer was feasible with a dose escalation to 99% of the tumors. Replanning resulted in an increased tumor dose that correlated well with the prediction model. The model was able to identify tumors on which a higher boost dose could be planned. The model has potential as a quality assessment tool in focal dose escalated treatment plans., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: To investigate whether magnesium oxide during external-beam radiotherapy for prostate cancer reduces intrafraction prostate motion in a double-blind, placebo-controlled randomized trial., Methods and Materials: At the Department of Radiotherapy, prostate cancer patients scheduled for intensity-modulated radiotherapy (77 Gy in 35 fractions) using fiducial marker-based position verification were randomly assigned to receive magnesium oxide (500 mg twice a day) or placebo during radiotherapy. The primary outcome was the proportion of patients with clinically relevant intrafraction prostate motion, defined as the proportion of patients who demonstrated in ≥ 50% of the fractions an intrafraction motion outside a range of 2 mm. Secondary outcome measures included quality of life and acute toxicity., Results: In total, 46 patients per treatment arm were enrolled. The primary endpoint did not show a statistically significant difference between the treatment arms with a percentage of patients with clinically relevant intrafraction motion of 83% in the magnesium oxide arm as compared with 80% in the placebo arm (p = 1.00). Concerning the secondary endpoints, exploratory analyses demonstrated a trend towards worsened quality of life and slightly more toxicity in the magnesium oxide arm than in the placebo arm; however, these differences were not statistically significant., Conclusions: Magnesium oxide is not effective in reducing the intrafraction prostate motion during external-beam radiotherapy, and therefore there is no indication to use it in clinical practice for this purpose., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: To evaluate the effect of an antiflatulent dietary advice on the intrafraction prostate motion in patients treated with intensity-modulated radiotherapy (IMRT) for prostate cancer., Methods and Materials: Between February 2002 and December 2009, 977 patients received five-beam IMRT for prostate cancer to a dose of 76 Gy in 35 fractions combined with fiducial markers for position verification. In July 2008, the diet, consisting of dietary guidelines to obtain regular bowel movements and to reduce intestinal gas by avoiding certain foods and air swallowing, was introduced to reduce the prostate motion. The intrafraction prostate movement was determined from the portal images of the first segment of all five beams. Clinically relevant intrafraction motion was defined as ≥50% of the fractions with an intrafraction motion outside a range of 3 mm., Results: A total of 739 patients were treated without the diet and 105 patients were treated with radiotherapy after introduction of the diet. The median and interquartile range of the average intrafraction motion per patient was 2.53 mm (interquartile range, 2.2-3.0) without the diet and 3.00 mm (interquartile range, 2.4-3.5) with the diet (p < .0001). The percentage of patients with clinically relevant intrafraction motion increased statistically significant from 19.1% without diet to 42.9% with a diet (odds ratio, 3.18; 95% confidence interval, 2.07-4.88; p < .0001)., Conclusions: The results of the present study suggest that antiflatulent dietary advice for patients undergoing IMRT for prostate cancer does not reduce the intrafraction movement of the prostate. Therefore, antiflatulent dietary advice is not recommended in clinical practice for this purpose., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Purpose: To investigate the influence of translational and rotational errors on prostate intensity-modulated radiotherapy (IMRT) with an integrated boost to the tumor and to evaluate the effect of the use of an on-line correction protocol., Methods and Materials: For 19 patients, who had been treated with prostate IMRT and fiducial marker-based position verification, highly inhomogeneous IMRT plans, including an integrated tumor boost, were made using varying margins (2, 4, 6, and 8 mm). The measured translational and rotational errors were used to calculate the dose using two positioning strategies: an off-line and an on-line protocol to correct the translational shifts. The estimated dose to the targets and the organs at risk was compared with the intended dose., Results: Residual deviations after off-line correction led to statistically significant, but very small, reductions in dose coverage. Even when a 2-mm margin was used, the average reduction in dose to 99% of the volume was 1.4 +/- 1.9 Gy for the tumor, 1.5 +/- 1.5 Gy for the prostate without seminal vesicles (boost volume), and 4.3 +/- 4.6 Gy, including the seminal vesicles (clinical target volume). Patients with large systematic rotational errors demonstrated a substantial decrease in dose, especially for the clinical target volume. If an on-line correction protocol was used, the average mean dose and dose to 99% of the volume of the targets improved. However, the extensive dose reduction for patients with large rotational errors barely recovered with on-line correction., Conclusion: For complex prostate IMRT with an integrated tumor boost, the use of an on-line correction protocol yields little improvement without the correction of rotational errors.

Purpose: To analyze the intrafraction motion of the prostate during external-beam radiation therapy of patients with prostate cancer., Methods and Materials: Between August 2001-December 2005, 427 patients with Stage T3Nx/0Mx/0 prostate carcinoma received intensity-modulated radiation therapy treatment combined with position verification with fiducial gold markers. For a total of 11,426 treatment fractions (average, 27 per patient), portal images were taken of the first segment of all five beams. The irradiation time of the technique varied between 5-7 min. From these data, the location of gold markers could be established within every treatment beam under the assumption of minimal marker movement., Results: In 66% of treatment fractions, a motion outside a range of 2 mm was observed, with 28% outside a range of 3 mm. The intrafraction marker movements showed that motion directions were often reversed. However, the effect was small. Even with perfect online position-correction at the start of irradiation, intrafraction motion caused position uncertainty, but systematic errors (Sigma) were limited to <0.6 mm, and random errors (sigma) to <0.9 mm. This would result in a lower limit of 2 mm for margins, in the absence of any other uncertainties., Conclusions: Intrafraction motion of the prostate occurs frequently during external-beam irradiation on a time scale of 5-7 min. Margins of 2 mm account for these intrafraction motions. However, larger margins are required in practice to accommodate other uncertainties in the treatment.