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Title: Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy

Abstract

The 3-dimensional conformal radiotherapy (3DCRT) technique is the standard for breast cancer radiotherapy. During treatment planning, not only the coverage of the planning target volume (PTV) but also the minimization of the dose to critical structures, such as the lung, heart, and contralateral breast tissue, need to be considered. Because of the complexity and variations of patient anatomy, more advanced radiotherapy techniques are sometimes desired to better meet the planning goals. In this study, we evaluated external-beam radiation treatment techniques for left breast cancer using various delivery platforms: fixed-field including TomoDirect (TD), static intensity-modulated radiotherapy (sIMRT), and rotational radiotherapy including Elekta volumetric-modulated arc therapy (VMAT) and tomotherapy helical (TH). A total of 10 patients with left-sided breast cancer who did or did not have positive lymph nodes and were previously treated with 3DCRT/sIMRT to the entire breast were selected, their treatment was planned with Monaco VMAT, TD, and TH. Dosimetric parameters including PTV coverage, organ-at-risk (OAR) sparing, dose-volume histograms, and target minimum/maximum/mean doses were evaluated. It is found that for plans providing comparable PTV coverage, the Elekta VMAT plans were generally more inhomogeneous than the TH and TD plans. For the cases with regional node involvement, the average mean dosesmore » administered to the heart were 9.2 (± 5.2) and 8.8 (± 3.0) Gy in the VMAT and TH plans compared with 11.9 (± 6.4) and 11.8 (± 9.2) Gy for the 3DCRT and TD plans, respectively, with slightly higher doses given to the contralateral lung or breast or both. On average, the total monitor units for VMAT plans are 11.6% of those TH plans. Our studies have shown that VMAT and TH plans offer certain dosimetric advantages over fixed-field IMRT plans for advanced breast cancer requiring regional nodal treatment. However, for early-stage breast cancer fixed-field radiotherapy is potentially more beneficial in terms of OAR sparing.« less

Authors:
 [1];  [2]; ; ; ;  [3];  [4]
  1. Department of Radiation Oncology, University of California Los Angeles, Los Angeles, CA (United States)
  2. Department of Radiology, Baylor College of Medicine, Houston, TX (United States)
  3. Department of Radiation Oncology, University of Colorado, Denver, CO (United States)
  4. Department of Radiation Oncology, Duke University, Durham, NC (United States)
Publication Date:
OSTI Identifier:
22420850
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Dosimetry; Journal Volume: 39; Journal Issue: 3; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; ANATOMY; COMPARATIVE EVALUATIONS; COMPUTERIZED TOMOGRAPHY; CT-GUIDED RADIOTHERAPY; HEART; LUNGS; LYMPH NODES; MAMMARY GLANDS; NEOPLASMS; PATIENTS; PLANNING; RADIATION DOSES

Citation Formats

Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu, Liu, Tian X., Liu, Arthur K., Newman, Francis, Rabinovitch, Rachel, Kavanagh, Brian, and Hu, Y. Angie. Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy. United States: N. p., 2014. Web. doi:10.1016/J.MEDDOS.2014.02.005.
Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu, Liu, Tian X., Liu, Arthur K., Newman, Francis, Rabinovitch, Rachel, Kavanagh, Brian, & Hu, Y. Angie. Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy. United States. doi:10.1016/J.MEDDOS.2014.02.005.
Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu, Liu, Tian X., Liu, Arthur K., Newman, Francis, Rabinovitch, Rachel, Kavanagh, Brian, and Hu, Y. Angie. 2014. "Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy". United States. doi:10.1016/J.MEDDOS.2014.02.005.
@article{osti_22420850,
title = {Left-sided breast cancer irradiation using rotational and fixed-field radiotherapy},
author = {Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu and Liu, Tian X. and Liu, Arthur K. and Newman, Francis and Rabinovitch, Rachel and Kavanagh, Brian and Hu, Y. Angie},
abstractNote = {The 3-dimensional conformal radiotherapy (3DCRT) technique is the standard for breast cancer radiotherapy. During treatment planning, not only the coverage of the planning target volume (PTV) but also the minimization of the dose to critical structures, such as the lung, heart, and contralateral breast tissue, need to be considered. Because of the complexity and variations of patient anatomy, more advanced radiotherapy techniques are sometimes desired to better meet the planning goals. In this study, we evaluated external-beam radiation treatment techniques for left breast cancer using various delivery platforms: fixed-field including TomoDirect (TD), static intensity-modulated radiotherapy (sIMRT), and rotational radiotherapy including Elekta volumetric-modulated arc therapy (VMAT) and tomotherapy helical (TH). A total of 10 patients with left-sided breast cancer who did or did not have positive lymph nodes and were previously treated with 3DCRT/sIMRT to the entire breast were selected, their treatment was planned with Monaco VMAT, TD, and TH. Dosimetric parameters including PTV coverage, organ-at-risk (OAR) sparing, dose-volume histograms, and target minimum/maximum/mean doses were evaluated. It is found that for plans providing comparable PTV coverage, the Elekta VMAT plans were generally more inhomogeneous than the TH and TD plans. For the cases with regional node involvement, the average mean doses administered to the heart were 9.2 (± 5.2) and 8.8 (± 3.0) Gy in the VMAT and TH plans compared with 11.9 (± 6.4) and 11.8 (± 9.2) Gy for the 3DCRT and TD plans, respectively, with slightly higher doses given to the contralateral lung or breast or both. On average, the total monitor units for VMAT plans are 11.6% of those TH plans. Our studies have shown that VMAT and TH plans offer certain dosimetric advantages over fixed-field IMRT plans for advanced breast cancer requiring regional nodal treatment. However, for early-stage breast cancer fixed-field radiotherapy is potentially more beneficial in terms of OAR sparing.},
doi = {10.1016/J.MEDDOS.2014.02.005},
journal = {Medical Dosimetry},
number = 3,
volume = 39,
place = {United States},
year = 2014,
month =
}
  • Purpose: To compare the dosimetric characteristics of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for left-sided breast cancer patients with modified radical mastectomy. Methods: Twenty-four left-sided breast cancer patients treated with modified radical mastectomy were selected in this study. The planning target volume (PTV) was generated by using 7-mm uniform expansion of the clinical target volume (CTV) in all direction except the skin surface. The organs at risk (OARs) included heart, left lung, right lung, and right breast. Dose volume histograms (DVHs) were utilized to evaluate the dose distribution in PTV and OARs. Results: Bothmore » VMAT and IMRT plans met the requirement of PTV coverage. VMAT was superior to IMRT in terms of conformity, with a statistically significant difference (p=0.024). Mean doses, V5 and V10 of heart and both lungs in VMAT plans were significantly decreased compared to IMRT plans (P<0.05), but in terms of heart volume irradiated by high doses (V30 and V45), no significant differences were observed (P>0.05). For right breast, VMAT showed the reduction of V5 in comparison with IMRT (P<0.05). Additionally, the mean number of monitor units (MU) and treatment time in VMAT (357.21, 3.62 min) were significantly less than those in IMRT (1132.85, 8.74 min). Conclusion: VMAT showed similar PTV coverage and significant advantage in OARs sparing compared with IMRT, especially in terms of decreased volumes irradiated by low doses, while significantly reducing the treatment time and MU number.« less
  • Purposes: There has been growing interest in treating breast cancer using VMAT technique. Our goal is to compare the dosimetry and treatment delivery parameters for the left-sided breast cancer treatment using various VMAT platforms from commercially available planning systems. Methods: Five consecutive left-sided breast cancer patients initially treated with conventional 3D-conformal radiotherapy (3DCRT) were selected. Four VMAT plans using most popular treatment planning systems, including Eclipse (Version 11, Varian), Pinnacle (Version 9.8, Philips), Monaco (Version 2.03, Elekta) and helical Tomotherapy (V4.0, Accuray). The same structure set and same planning goals were used for all VMAT plans. The dosimetric parameters includingmore » target coverage and minimum/maximum/mean, dose-volume endpoints for the selected normal structures: the heart, ipsilateral-/contralateral lung and breast, were evaluated. Other dosimetric indices including heterogeneity index (HI) were evaluated. The treatment delivery parameters, such as monitor unit (MUs) and delivery time were also compared. Results: VMAT increases dose homogeneity to the treated volume and reduces the irradiated heart and left-lung volumes. Compared to the 3DCRT technique, all VMAT plans offer better heart and left-lung dose sparing; the mean heart doses were 4.5±1.6(Monaco), 1.2±0.4(Pinnacle), 1.3± (Eclipse) and 5.6±4.4(Tomo), the mean left-lung doses were 5.9±1.5(Monaco), 3.7±0.7(Pinnacle), 1.4± (Eclipse) and 5.2±1.6 (Tomo), while for the 3DCRT plan, the mean heart and left-Lung doses were 2.9±2.0, and 6.8±4.4 (Gy) respectively. The averaged contralateral-breast and lung mean doses were higher in VMAT plans than the 3DCRT plans but were not statistically significant. Among all the VMAT plans, the Pinnacle plans often yield the lowest right-lung/breast mean doses, and slightly better heterogeneity indices that are similar to Tomotherapy plans. Treatment delivery time of the VMAT plans (except helical Tomotherapy IMRT) is estimated to be comparable with the conventional 3DCRT. Conclusion: VMAT achieves equal or better PTV coverage and comparable OARs sparing compared to the conventional 3DCRT techniques.« less
  • Purpose: We evaluated heart sparing using an intensity-modulated radiotherapy (IMRT) plan with the left ventricle (LV) and/or the anterior myocardial territory (AMT) as additional organs at risk (OARs). Methods and Materials: A total of 10 patients with left-sided breast cancer were selected for dosimetric planning. Both lungs, the right breast, heart, LV, and AMT were defined as OARs. We generated one tangential field plan and four IMRT plans for each patient. We examined the dose-volume histogram parameters of the planning target volume and OARs. Results: Compared with the tangential field plan, the mean dose to the heart in the IMRTmore » plans did not show significant differences; however, the dose to the AMT and LV decreased by 18.7-45.4% and 10.8-37.4%, respectively. The maximal dose to the heart decreased by 18.6-35.3%, to the AMT by 22.0-45.1%, and to the LV by 23.5-45.0%, And the relative volumes of the heart (V{sub {>=}12}), AMT (V{sub >11}) and LV (V{sub >10}) decreased significantly with different levels, respectively. The volume of the heart, AMT, LV, both lungs, and right breast receiving {>=}5 Gy showed a significant increase. Compared with the IMRT (H) plan, the mean dose to the heart, AMT, and LV decreased by 17.5-21.5%, 25.2-29.8%, and 22.8-29.8% and the maximal dose by 13.6-20.6%, 23.1-29.6%, and 17.3-29.1%, respectively. The IMRT plans for both lungs and the right breast showed no significant differences. Conclusions: The IMRT plans with the addition of the AMT and/or LV as OARs considerably increased heart sparing. We recommend including the LV as an additional OAR in such plans.« less
  • Purpose: To evaluate the dosimetric benefit of prone breast radiotherapy for Korean left-sided early-stage breast cancer patients who have relatively small breast Methods: From April to June, 2014, 10 left-sided breast cancer patients received the whole breast irradiation in prone position after partial mastectomy with sentinel lymph node biopsy or axillary lymph node dissection. All patients were pTmi-2N0-1mi. Each patient underwent two computed tomoradiography (CT) simulations in supine and prone positions. The whole breast, ipsilateral lung, heart, and left anterior descending coronary artery (LAD) were contoured on each simulation CT images, and then tangential-fields treatment plan in each position wasmore » designed for the whole breast irradiation with the total dose of 50 Gy in 2 Gy fractions. Dose-volume histograms of two setups were compared for target coverage and radiation dose to normal organs with Wilcoxon signed rank tests. Results: The median age of patients was 47 years (range, 37 to 53). The median chest size was 82.5 cm (range, 75 to 90) and bra cup size was A in 4, B in 4, and C in 2 patients. The radiation dose to the whole breast was similar when comparing mean dose (Dmean) and dose covering 95% of the breast volume, but maximum dose (Dmax) of breast was higher in supine (median 52.3 vs. 52.7 Gy, p=0.013). Prone position reduced significantly the radiation dose in ipsilateral lung, heart, and LAD by median 5.7, 1.1, and 6.9 Gy of Dmean (p=0.005, 0.007, and 0.005) and 28.2, 18.8, and 35.0 Gy of Dmax (p=0.005, 0.005, and 0.007), respectively. Conclusion: Prone breast radiotherapy could be beneficial for Korean breast cancer patients since it substantially spared normal organs while achieving adequate coverage of the breast tissue. Further prospective study is required to validate the potential benefit of prone breast radiotherapy.« less
  • Purpose: Volumetric modulated arc therapy (VMAT) is a novel extension of conventional intensity-modulated radiotherapy (cIMRT), in which an optimized three-dimensional dose distribution may be delivered in a single gantry rotation. VMAT is the predecessor to RapidArc (Varian Medical System). This study compared VMAT with cIMRT and with conventional modified wide-tangent (MWT) techniques for locoregional radiotherapy for left-sided breast cancer, including internal mammary nodes. Methods and Materials: Therapy for 5 patients previously treated with 50 Gy/25 fractions using nine-field cIMRT was replanned with VMAT and MWT. Comparative endpoints were planning target volume (PTV) dose homogeneity, doses to surrounding structures, number ofmore » monitor units, and treatment delivery time. Results: For VMAT, two 190 deg. arcs with 2-cm overlapping jaws were required to optimize over the large treatment volumes. Treatment plans generated using VMAT optimization resulted in PTV homogeneity similar to that of cIMRT and MWT. The average heart volumes receiving >30 Gy for VMAT, cIMRT, and MWT were 2.6% +- 0.7%, 3.5% +- 0.8%, and 16.4% +- 4.3%, respectively, and the average ipsilateral lung volumes receiving >20 Gy were 16.9% +- 1.1%, 17.3% +- 0.9%, and 37.3% +- 7.2%, respectively. The average mean dose to the contralateral medial breast was 3.2 +- 0.6 Gy for VMAT, 4.3 +- 0.4 Gy for cIMRT, and 4.4 +- 4.7 Gy for MWT. The healthy tissue volume percentages receiving 5 Gy were significantly larger with VMAT (33.1% +- 2.1%) and IMRT (45.3% +- 3.1%) than with MWT (19.4% +- 3.7%). VMAT reduced the number of monitor units by 30% and the treatment time by 55% compared with cIMRT. Conclusions: VMAT achieved similar PTV coverage and sparing of organs at risk, with fewer monitor units and shorter delivery time than cIMRT.« less