A randomised controlled trial of forward-planned radiotherapy (IMRT) for early breast cancer: baseline characteristics and dosimetry results.
ABSTRACT This large trial was designed to investigate whether correction of dose inhomogeneities using intensity-modulated radiotherapy (IMRT) reduces late toxicity and improves quality of life in patients with early breast cancer. This paper reports baseline characteristics of trial participants and dosimetry results.
Standard tangential plans of 1145 trials were analysed. Patients with inhomogeneous plans, defined by ICRU recommendations, were randomised to forward-planned IMRT or standard radiotherapy.
Twenty-nine percentage of patients had adequate dosimetry with standard 2D radiotherapy. In the randomised patients, the decreases in mean volumes receiving greater than 107% (Vol>107) and less than 95% (Vol<95) of the prescribed dose in the IMRT compared with the control group were 34.0 cm(3) (95% CI 26.4-41.6; P<0.0001) and 48.1 cm(3) (95% CI 34.4-61.9; P<0.0001), respectively. In this study, 90% of patients who had a breast separation greater > or = 21 cm had Vol>107>2 cm(3) on standard radiotherapy plans.
This large trial, in which patients with all breast sizes were eligible, confirmed that breast dosimetry can be significantly improved with a simple method of forward-planned IMRT and has little impact on radiotherapy resources. It is shown that patients with larger breasts are more likely to have dose inhomogeneities and breast separation gives some indication of this likelihood. Photographic assessment of patients at 2 years after radiotherapy, as the next part of this randomised controlled trial, will show whether these results for IMRT translate into improved cosmetic outcome in patients with early breast cancer. This would provide impetus for the widespread adoption of 3D planning and IMRT.
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ABSTRACT: Purpose To determine whether Cherenkov light imaging can visualize radiation therapy in real time during breast radiation therapy. Methods and Materials An intensified charge-coupled device (CCD) camera was synchronized to the 3.25-μs radiation pulses of the clinical linear accelerator with the intensifier set × 100. Cherenkov images were acquired continuously (2.8 frames/s) during fractionated whole breast irradiation with each frame an accumulation of 100 radiation pulses (approximately 5 monitor units). Results The first patient images ever created are used to illustrate that Cherenkov emission can be visualized as a video during conditions typical for breast radiation therapy, even with complex treatment plans, mixed energies, and modulated treatment fields. Images were generated correlating to the superficial dose received by the patient and potentially the location of the resulting skin reactions. Major blood vessels are visible in the image, providing the potential to use these as biological landmarks for improved geometric accuracy. The potential for this system to detect radiation therapy misadministrations, which can result from hardware malfunction or patient positioning setup errors during individual fractions, is shown. Conclusions Cherenkoscopy is a unique method for visualizing surface dose resulting in real-time quality control. We propose that this system could detect radiation therapy errors in everyday clinical practice at a time when these errors can be corrected to result in improved safety and quality of radiation therapy.International journal of radiation oncology, biology, physics 01/2014; · 4.59 Impact Factor
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ABSTRACT: To evaluate the dosimetric gain obtained in either the planning target volume or organs at risk coverage by the use of intensity-modulated radiation therapy in some particular postoperative breast cancers. Prospective dosimetric comparison between monoisocentric conformal radiotherapy and intensity-modulated radiation therapy in nine patient files. Using intensity-modulated radiation therapy was shown to improve in each case, at least one conformity, homogeneity, and coverage index either for planning target volumes or for organs at risk. Intensity-modulated radiation therapy was therefore always chosen rather than conformal monoisocentric radiotherapy. Indications to retain intensity-modulated radiation therapy would consist of bilateral lesions, pectus excavatum, past thoracic irradiation (Hodgkin's disease) and complex volumes in obese or overweight patients.Cancer/Radiothérapie 12/2013; · 1.48 Impact Factor
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ABSTRACT: The use of intensity-modulated radiotherapy (IMRT) in breast cancer reduces clinician-assessed breast tissue toxicity including fibrosis, telangectasia and sub-optimal cosmesis. Patient reported outcome measures (PROMs) are also important as they provide the patient's perspective. This longitudinal study reports on (a) the effect of forward planned field-in-field IMRT (∼simple IMRT) on PROMs compared to standard RT at 5years after RT, (b) factors affecting PROMs at 5years after RT and (c) the trend of PROMs over 5years of follow up. PROMs were assessed at baseline (pre-RT), 6, 24 and 60months after completion of RT using global health (EORTC QLQ C30) and 4 breast symptom questions (BR23). Also, 4 breast RT-specific questions were included at 6, 24 and 60months: change in skin appearance, firmness to touch, reduction in breast size and overall change in breast appearance since RT. The benefits of simple IMRT over standard RT at 5years after RT were assessed using standard t-test for global health and logistic regression analysis for breast symptom questions and breast RT-specific questions. Clinical factors affecting PROMs at 5years were investigated using a multivariate analysis. A repeated mixed model was applied to explore the trend over time for each of PROMs. (89%) 727/815, 84%, 81% and 61% patients completed questionnaires at baseline, 6, 24 and 60months respectively. Patients reported worse toxicity for all four BR23 breast symptoms at 6months, which then improved over time (p<0.0001). They also reported improvement in skin appearance and breast hardness over time (p<0.0001), with no significant change for breast shrinkage (p=0.47) and overall breast appearance (p=0.13). At 5years, PROMs assessments did not demonstrate a benefit for simple IMRT over standard radiotherapy. Large breast volume, young age, baseline surgical cosmesis and post-operative infection were the most important variables to affect PROMs. This study was unable to demonstrate the benefits of IMRT on PROMs at 5years. PROMs are influenced by non-radiotherapy factors and surgical factors should be optimised to improve patients' outcome. Only a small proportion of patients report moderate-severe breast changes post radiotherapy, with most PROMs improving over time. The difference in clinician assessment and PROMs outcome requires further investigation.Radiotherapy and Oncology 04/2014; · 4.52 Impact Factor