| 1. |
- Mavroidis, Panayiotis, et al.
(author)
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Comparison of Different Fractionation Schedules Toward a Single Fraction in High-Dose-Rate Brachytherapy as Monotherapy for Low-Risk Prostate Cancer Using 3-Dimensional Radiobiological Models
- 2014
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In: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 88:1, s. 216-223
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Journal article (peer-reviewed)abstract
- Purpose: The aim of the present study was the investigation of different fractionation schemes to estimate their clinical impact. For this purpose, widely applied radiobiological models and dosimetric measures were used to associate their results with clinical findings. Methods and Materials: The dose distributions of 12 clinical high-dose-rate brachytherapy implants for prostate were evaluated in relation to different fractionation schemes. The fractionation schemes compared were: (1) 1 fraction of 20 Gy; (2) 2 fractions of 14 Gy; (3) 3 fractions of 11 Gy; and (4) 4 fractions of 9.5 Gy. The clinical effectiveness of the different fractionation schemes was estimated through the complication-free tumor control probability (P (+)), the biologically effective uniform dose, and the generalized equivalent uniform dose index. Results: For the different fractionation schemes, the tumor control probabilities were 98.5% in 1 x 20 Gy, 98.6% in 2 x 14 Gy, 97.5% in 3 x 11 Gy, and 97.8% in 4 x 9.5 Gy. The corresponding P+ values were 88.8% in 1 x 20 Gy, 83.9% in 2 x 14 Gy, 86.0% in 3 x 11 Gy, and 82.3% in 4 x 9.5 Gy. With use of the fractionation scheme 4 x 9.5 Gy as reference, the isoeffective schemes regarding tumor control for 1, 2, and 3 fractions were 1 x 19.68 Gy, 2 x 13.75 Gy, and 3 x 11.05 Gy. The optimum fractionation schemes for 1, 2, 3, and 4 fractions were 1 x 19.16 Gy with a P+ of 91.8%, 2 x 13.2 Gy with a P+ of 89.6%, 3 x 10.6 Gy with a P+ of 88.4%, and 4 x 9.02 Gy with a P+ of 86.9%. Conclusions: Among the fractionation schemes 1 (+) 20 Gy, 2 (+) 14 Gy, 3 x 11 Gy, and 4 x 9.5 Gy, the first scheme was more effective in terms of P+. After performance of a radiobiological optimization, it was shown that a single fraction of 19.2 to 19.7 Gy (average 19.5 Gy) should produce at least the same benefit as that given by the 4 x 9.5 Gy scheme, and it should reduce the expected total complication probability by approximately 40% to 55%.
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| 2. |
- Milickovic, Natasa, et al.
(author)
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4D analysis of influence of patient movement and anatomy alteration on the quality of 3D U/S-based prostate HDR brachytherapy treatment delivery
- 2011
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In: Medical physics (Lancaster). - : Wiley. - 0094-2405. ; 38:9, s. 4982-4993
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Journal article (peer-reviewed)abstract
- Purpose: Modern HDR brachytherapy treatment for prostate cancer based on the 3D ultrasound (U/S) plays increasingly important role. The purpose of this study is to investigate possible patient movement and anatomy alteration between the clinical image set acquisition, made after the needle implantation, and the patient irradiation and their influence on the quality of treatment. Methods: The authors used 3D U/S image sets and the corresponding treatment plans based on a 4D-treatment planning procedure: plans of 25 patients are obtained right after the needle implantation (clinical plan is based on this 3D image set) and just before and after the treatment delivery. The authors notice the slight decrease of treatment quality with increase of time gap between the clinical image set acquisition and the patient irradiation. 4D analysis of dose-volume-histograms (DVHs) for prostate: CTV1 - PTV, and urethra, rectum, and bladder as organs at risk (OARs) and conformity index (COIN) is presented, demonstrating the effect of prostate, OARs, and needles displacement. Results: The authors show that in the case that the patient body movement/anatomy alteration takes place, this results in modification of DVHs and radiobiological parameters, hence the plan quality. The observed average displacement of needles (1 mm) and of prostate (0.57 mm) is quite small as compared with the average displacement noted in several other reports [A. A. Martinez et al., Int. J. Radiat. Oncol., Biol., Phys. 49(1), 61-69 (2001); S. J. Damore et al., Int. J. Radiat. Oncol., Biol., Phys. 46(5), 1205-1211 (2000); P. J. Hoskin et al., Radiotherm. Oncol. 68(3), 285-288 (2003); E. Mullokandov et al., Int. J. Radiat. Oncol., Biol., Phys. 58(4), 1063-1071 (2004)] in the literature. Conclusions: Although the decrease of quality of dosimetric and radiobiological parameters occurs, this does not cause clinically unacceptable changes to the 3D dose distribution, according to our clinical protocol. (C) 2011 American Association of Physicists in Medicine. [DOI: 10.1118/1.3618735]
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| 3. |
- Glatzer, Markus, et al.
(author)
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Role of Brachytherapy in the Postoperative Management of Endometrial Cancer : Decision-Making Analysis among Experienced European Radiation Oncologists
- 2022
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In: Cancers. - : MDPI. - 2072-6694. ; 14:4
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Journal article (peer-reviewed)abstract
- BACKGROUND: There are various society-specific guidelines addressing adjuvant brachytherapy (BT) after surgery for endometrial cancer (EC). However, these recommendations are not uniform. Against this background, clinicians need to make decisions despite gaps between best scientific evidence and clinical practice. We explored factors influencing decision-making for adjuvant BT in clinical routine among experienced European radiation oncologists in the field of gynaecological radiotherapy (RT). We also investigated the dose and technique of BT.METHODS: Nineteen European experts for gynaecological BT selected by the Groupe Européen de Curiethérapie and the European Society for Radiotherapy & Oncology provided their decision criteria and technique for postoperative RT in EC. The decision criteria were captured and converted into decision trees, and consensus and dissent were evaluated based on the objective consensus methodology.RESULTS: The decision criteria used by the experts were tumour extension, grading, nodal status, lymphovascular invasion, and cervical stroma/vaginal invasion (yes/no). No expert recommended adjuvant BT for pT1a G1-2 EC without substantial LVSI. Eighty-four percent of experts recommended BT for pT1a G3 EC without substantial LVSI. Up to 74% of experts used adjuvant BT for pT1b LVSI-negative and pT2 G1-2 LVSI-negative disease. For 74-84% of experts, EBRT + BT was the treatment of choice for nodal-positive pT2 disease and for pT3 EC with cervical/vaginal invasion. For all other tumour stages, there was no clear consensus for adjuvant treatment. Four experts already used molecular markers for decision-making. Sixty-five percent of experts recommended fractionation regimens of 3 × 7 Gy or 4 × 5 Gy for BT as monotherapy and 2 × 5 Gy for combination with EBRT. The most commonly used applicator for BT was a vaginal cylinder; 82% recommended image-guided BT.CONCLUSIONS: There was a clear trend towards adjuvant BT for stage IA G3, stage IB, and stage II G1-2 LVSI-negative EC. Likewise, there was a non-uniform pattern for BT dose prescription but a clear trend towards 3D image-based BT. Finally, molecular characteristics were already used in daily decision-making by some experts under the pretext that upcoming trials will bring more clarity to this topic.
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