Skip to main content
NCBI home page
Medicine logoLink to Medicine
. 2019 Sep 27;98(39):e17340. doi: 10.1097/MD.0000000000017340

Evaluation of abches and volumetric modulated arc therapy under deep inspiration breath-hold technique for patients with left-sided breast cancer

A retrospective observational study

Tien-Chi Yeh a, Mau-Shin Chi a, Kwan-Hwa Chi a,b, Chung-Hsien Hsu a,∗
Editor: YX Sun
PMCID: PMC6775396  PMID: 31574873

Abstract

Radiotherapy after breast-conserving surgery or mastectomy has clinical benefits including reducing local recurrence and improving overall survival. Deep inspiration breath-hold (DIBH) technique using the Abches system is an easy and practical method to reduce radiation dose to the heart and lungs. This retrospective study was proposed to investigate the dosimetric difference between Abches system and free breathing technique in treating left-sided breast cancer.

Eligible patients underwent computed tomography (CT) scans to acquire both free breathing (FB) and DIBH technique data using the Abches. For each patient, both FB and DIBH image sets were planned based on the volumetric modulated arc therapy (VMAT). Radiation dose to the heart, ipsilateral lung, and contralateral lung was compared between the Abches system and FB.

No significant differences in the planning target volume (PTV) (674.58 vs 665.88 cm3, P = .29), mean dose (52.28 vs 52.03 Gy, P = .13), and volume received at the prescribed dose (Vpd) (94.66% vs 93.92%, P = .32) of PTV were observed between the FB and DIBH plans. Significant differences were found in mean heart (6.71 Gy vs 4.21 Gy, P < .001), heart V5 (22.73% vs 14.39%, P = .002), heart V20 (10.96% vs. 5.62%, P < .001), mean left lung (11.51 vs 10.07 Gy, P = .01), left lung V20 (22.88% vs 19.53%, P = .02), left lung V30 (18.58 vs 15.27%, P = .005), and mean right lung dose (.89 vs 72 Gy, P = .03).

This is the first report on reduced mean left lung, mean right lung dose, and V20 of left lung using VMAT and Abches. The combination of Abches and VMAT can practically and efficiently reduce extraradiation doses to the heart and lungs.

Keywords: abches, breast cancer, deep inspiration breath-hold, volumetric modulated arc therapy

1. Introduction

Adjuvant radiotherapy for breast ductal carcinoma in situ (DCIS) or breast carcinomas has shown clinical benefits to reduce local recurrence and improve overall survival.[1,2] The radiation field covering the whole breast and regional lymph nodes (axillary, supraclavicular, and internal mammary) further decreases local regional and distant recurrences in node-positive patients. However, low-dose radiation exposure to the heart and lungs increased by regional nodal irradiation.[3,4] The risk of late cardiac and pulmonary toxicities has been documented many years after the radiation in long-term survivors with previous chest irradiation.[5,6] Darby et al even reported a 7.4% increase per Gray (Gy) in major coronary events after a radiation exposure to the heart that persists for >10 years.[6,7] Increased late toxicities raised concerns in treating patients with underlying comorbidities.[5]

The deep inspiration breath-hold (DIBH) techniques, such as abdominal chest (Abches) system, real-time position management (RPM) system, or active breathing control (ABC),[8–11] were practical methods used to reduce radiation exposure to the heart and lungs.[8,12–15] The goal of DIBH was to create maximal separation of the target area (chest wall and regional lymph nodes) from the heart and thus minimize the irradiated heart volume by treating at or near the maximal inspiration. However, DIBH techniques were not routinely used in daily clinical practice, mainly because of the cost of additional equipment and increased workloads.

Abches system, a self-monitoring respiratory device developed by Onishi et al, was a commercially available product from APEX Medical, Inc. Patients were instructed to hold their breath for >15 seconds during deep inspiration while radiotherapy was initiated. The whole treatment course was divided into certain cycles with different respiratory phases. Abches effectively decreased the radiation dose exposure in the heart and left anterior descending coronary artery by treating 2 opposing tangential conformal fields.[8] The volumetric modulated arc therapy (VMAT) is a modern radiotherapeutic technique in changing aperture shapes, dose rates, and gantry rotation speeds according to different gantry angles. It provided better sparing organs at risk (OARs), better dose homogeneity, better target conformity, and shorter treatment time.[16–21] VMAT using tangential partial arcs for the treatment revealed good target coverage and conformity as well as in decreasing OAR doses.[22–24] However, treatment using VMAT reported an increased low-dose radiation back to the normal structures.[25–27] This study aimed to compare the radiation doses in the heart, ipsilateral lung, and contralateral lung while treating patients with left-sided breast cancer using Abches or by free breathing (FB) using the tangential partial VMAT technique.

2. Material and methods

2.1. Patient selection

A total of 12 patients (mean age = 50.2, range: 38–69 years) with left-sided DCIS or breast cancer from stage I to III treated at our department using the Abches system from June 2015 to September 2016 were enrolled in this retrospective study. The chest wall with or without regional lymph nodes comprised the irradiated field (Table 1). Patients were required to hold their breath for at least 25 seconds. All patients underwent noncontrast computed tomography (CT) scans to acquire FB and DIBH using the Abches system. CT slices were obtained using a Discovery RT590 16 Slice CT scanner (General Electric Company, Waukesha, WI) with 5-mm thicknesses. Those who were not able to hold their breath for 25 seconds were excluded.

Table 1.

Patient characteristics included age, stage, and treatment site.

2.1.

Open in a new tab

2.2. Ethical approval

This retrospective study protocol was approved by the Institutional Review Board of Shin Kong Wu Ho Su Memorial Hospital (NO.20170406R).

2.3. DIBH technique using the abches system

Patients were immobilized using an alpha cradle in supine position with left arm over their heads. The main component of Abches was set over the iliac crest with two fulcrums placed and marked at the patient's sternum and abdomen. The Abches system was made from resin without electronic parts; thus, they only had minimal influence on dose calculation. A mirror was placed on the forehead to self-monitor each respiratory cycle by keeping 2 pointers on the body component in a certain point during each treatment cycle (Fig. 1). The outer pointer indicated the end of expiration and beginning of each inspiration; the inner marker was the inspiration level in which the patients hold their breath for >25 seconds. All patients were guided to repeat the sequence “breathe in, hold breath, and breath out” for several cycles. During the “breath in, hold breath” period, patients were instructed to hold their breath close to the maximum inspiration. Before the treatment, breathing exercises were required to achieve good reproducibility. The camera monitor was used to aid technicians in knowing whether the patients lost their breathing controllability and may interrupt the radiation beam immediately if needed.

Figure 1.

Figure 1

Open in a new tab

The Abches system. Outer markers (dark arrows) indicated the end of expiration and inspiration during each regular respiration. The middle marker indicated the inspiration level in which the patients could hold their breath for several seconds, and it was repeatable throughout the treatment course.

2.4. Treatment planning

For each patient, the clinical target volume was delineated based on the Radiation Therapy Oncology Group contouring atlas. The planning target volume (PTV) was 1 cm from the anterior and superior–inferior side and 5 mm from the left–right–posterior side. The prescribed dose was 50 Gy in 25 fractions to the PTV with a tumor bed boost of 10 Gy. The plan aimed to cover ≥95% of the PTV administered at the prescribed dose. The OAR goals were to obtain the lowest achievable doses in each structure.

Both FB and DIBH image sets were planned by the Pinnacle treatment planning system (Phillips Healthcare, Andover, MA, ver. 9.8.) using a dose grid size of 3 mm. About 2 to 4 coplanar tangential arcs using 6-MV photon in VMAT base were made in each CT scan delivered by an Elekta machine (Synergy). The average angle of gantry rotated was 45 degree in each arc. The gantry angle of the anterior side ranged between 290 and 310 degree and the opposite angle ranged between 100 and 120 degree.

2.5. Anatomic and dosimetric evaluation

Anatomic characteristics including the volume in the PTV, heart, left lung, and right lung between FB and DIBH scans were compared. For PTV, the mean dose, the volume received at the prescribed dose (Vpd%), and the near maximum dose that represented the highest dose received by 1% of the PTV volume were compared. For OARs, the mean dose in the heart; the volume of the heart receiving 5 Gy, 20 Gy, and 30 Gy; the mean dose in the left lung; the volume in the left lung receiving 5 Gy, 20 Gy, and 30 Gy; the mean dose in the right lung; and the volume in the right lung receiving 1 Gy were compared.

2.6. Statistical analysis

Dosimetric parameters and relative dose volume histograms between the treatment techniques were analyzed using Excel 2013 (Microsoft, Redmond, WA). Student paired t test (paired, 2-tailed) was used to compare each evaluation parameter at a significance level of P < .05.

3. Results

No significant differences in the PTV volume (674.58 vs 665.88 cm3, P = .29) and heart volume (595.17 vs 571.00 cm3, P = .15) were observed using the Abches system or FB. Significant enlargement of the left lung (1065.67 vs 1671.08 cm3, P < .001) and increase in right lung volume (1348.75 vs 2007.08 cm3, P < .001) were observed using the Abches (Table 2). The total lung volume increased from an average of 2414 (range: 1851–2866) mL in FB to 3678 (2474–5020) mL in DIBH. The CT scans of FB and DIBH of 1 patient are shown in Figure 2. The lung volume was expanded using the Abches, and the heart was shifted away from the chest wall. The arrows in Figure 2 pointed areas with lower radiation dose exposure to the heart in DIBH compared with that in FB. Within the prescribed dose of 5000 cGy, the radiation isodose lines showed both the high (2000 cGy and 3000 cGy) and low-dose regions (500 cGy) of the heart.

Table 2.

Comparison of volume parameters in cubic centimeters of 12 patients with left-sided breast cancer.

3.

Open in a new tab

Figure 2.

Figure 2

Open in a new tab

Computed tomography scans for both free breathing (FB) (left) and deep inspiration breath-hold (DIBH) (right) in 1 patient. The arrows pointing the heart were shifted away from the chest wall and received lesser radiation dose exposure in DIBH than in FB.

No significant differences were found in the PTV including the mean dose (52.28 vs 52.03 Gy, P = .13), Vpd (94.66% vs 93.92%, P = .32), and D1% (53.35 vs 54.10 Gy, P = .20) (Table 3). The lower dose exposure to the mean heart dose (6.71 vs 4.21 Gy, P < .001), heart V5 (22.73% vs 14.39%, P = .002), heart V20 (10.96% vs 5.62%, P < .001), heart V30 (8.33% vs 3.83%, P < .001), mean left lung dose (11.51 vs 10.07 Gy, P = .01), left lung V20 (22.88% vs 19.53%, P = .02), left lung V30 (18.58% vs 15.27%, P = .005), mean right lung dose (.89 vs 72 Gy, P = .03), and right lung V1 (26.24% vs 20.62%, P = .04) in Abches was significant. The overall treatment time was 10 to 15 minutes in FB and 15 to 20 minutes in Abches.

Table 3.

Comparison of dosimetric parameters in 12 patients with left-sided breast cancer.

3.

Open in a new tab

4. Discussion

A significantly reduced mean heart and lung dose can be achieved using the Abches even in an extended radiotherapy field covering the regional lymph nodes. Both high (20 and 30 Gy) and low (5 Gy) dose to the heart were decreased. The DIBH technique for patients with left-sided breast cancer displaced the heart from the breast radiation field to reduce the heart and coronary artery dose.[12] DIBH, irrespective of the technique chosen, lowered the mean heart dose.[8,12,28] The only topic that should be investigated using the Abches system was reported by Lee et al,[8] which assessed Abches combined with 3D tangential technique for the treatment of patients with left breast cancer. The study demonstrated a lower mean heart (2.52 vs 4.53 Gy) and lower mean left anterior descending artery dose.

The absolute volumes in both lungs were increased in DIBH. The lung density was decreased while expanding the lung volume; thus, a reduced fraction of a normal lung was irradiated.[29,30] This was the first study to report a decreased mean left lung (1007 vs 1151 cGy), mean right lung (72 vs 89 cGy), and left lung V20 (19.5 vs 22.9%) using the Abches. Compared with the 3D technique and VMAT, tangential VMAT planning produced lower OAR doses.[25] This may be the reason that our study showed a lower mean lung dose than 3D planning.

As expected, the exposed right lung dose was low in both arms. However, differences in the mean right lung and V1 were still significant. The mean right lung dose was also reduced by treating the right-sided breast cancer using a respiratory gating system.[31,32] Therefore, the Abches system was assumed to be also beneficial for the treatment of patients with right-sided breast cancer.

A reproducible inspiratory control was key in making maximal use of the DIBH technique, including the Abches, RPM systems, or ABC.[8–11,33] The high compliance level can be produced by repeating the pretreatment simulation trainings.[11] The planning physicists and technicians will be familiar with the daily setup and can provide correct instructions in a short time period. A longer overall treatment time is inevitable because the whole treatment course is divided into fractions. In our own experience, the extra time was short (10–15 minutes in FB and 15–20 minutes in Abches) and thus acceptable in daily clinical practice.

This retrospective study has several limitations. First, it was not a randomized study and the patients independently chose the Abches. Second, different radiation oncologists delineated the contours; thus, some personal variations exist. Third, treatment results and real long-term side effects were not reported because of the short follow-up period.

Our study showed that radiation doses to the heart, mean left lung, V20, and right lung were significantly decreased by the Abches system using the tangential partial VMAT technique. This may decrease the risk for radiation pneumonitis and future cardiac events. Therefore, the Abches system is recommended in treating patients with left-sided breast cancer and selected right-sided breast cancer.

Author contributions

Conceptualization: Chung-Hsien Hsu.

Formal analysis: Tien-Chi Yeh.

Supervision: Kwan-Hwa Chi, Chung-Hsien Hsu.

Writing – original draft: Tien-Chi Yeh.

Writing – review & editing: Mau-Shin Chi, Kwan-Hwa Chi.

Tien-Chi Yeh orcid: 0000-0002-1952-7246.

Footnotes

Abbreviations: ABC = active breathing control, CT = computed tomography, DCIS = ductal carcinoma in situ, DIBH = deep inspiration breath-hold, FB = free breathing, Gy = Gray, OARs = organs at risk, PTV = planning target volume, RPM = real-time position management, VMAT = volumetric modulated arc therapy, Vpd = volume received prescribed dose.

How to cite this article: Yeh TC, Chi MS, Chi KH, Hsu CH. Evaluation of abches and volumetric modulated arc therapy under deep inspiration breath-hold technique for patients with left-sided breast cancer. Medicine. 2019;98:39(e17340).

The authors report no conflicts of interest.

References

  • [1].Clarke M, Collins R, Darby S, et al. Effects of radiotherapy and of differences in the extent of surgery for early breast cancer on local recurrence and 15-year survival: an overview of the randomised trials. Lancet 2005;366:2087–106. [DOI] [PubMed] [Google Scholar]
  • [2].Darby S, McGale P, et al. Early Breast Cancer Trialists’ Collaborative G. Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: meta-analysis of individual patient data for 10,801 women in 17 randomised trials. Lancet 2011;378:1707–16. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [3].Whelan TJ, Olivotto IA, Parulekar WR, et al. Regional nodal irradiation in early-stage breast cancer. N Engl J Med 2015;373:307–16. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [4].Poortmans PM, Collette S, Kirkove C, et al. Internal mammary and medial supraclavicular irradiation in breast cancer. N Engl J Med 2015;373:317–27. [DOI] [PubMed] [Google Scholar]
  • [5].Chow TL, Louie AV, Palma DA, et al. Radiation-induced lung injury after concurrent neoadjuvant chemoradiotherapy for locally advanced breast cancer. Acta Oncol 2014;53:697–701. [DOI] [PubMed] [Google Scholar]
  • [6].Darby SC, Ewertz M, McGale P, et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med 2013;368:987–98. [DOI] [PubMed] [Google Scholar]
  • [7].Sardaro A, Petruzzelli MF, D’Errico MP, et al. Radiation-induced cardiac damage in early left breast cancer patients: risk factors, biological mechanisms, radiobiology, and dosimetric constraints. Radiother Oncol 2012;103:133–42. [DOI] [PubMed] [Google Scholar]
  • [8].Lee HY, Chang JS, Lee IJ, et al. The deep inspiration breath hold technique using Abches reduces cardiac dose in patients undergoing left-sided breast irradiation. Radiat Oncol J 2013;31:239–46. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [9].Mittauer KE, Deraniyagala R, Li JG, et al. Monitoring ABC-assisted deep inspiration breath hold for left-sided breast radiotherapy with an optical tracking system. Med Phys 2015;42:134–43. [DOI] [PubMed] [Google Scholar]
  • [10].Darapu A, Balakrishnan R, Sebastian P, et al. Is the deep inspiration breath-hold technique superior to the free breathing technique in cardiac and lung sparing while treating both left-sided post-mastectomy chest wall and supraclavicular regions? Case Rep Oncol 2017;10:37–51. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [11].Latty D, Stuart KE, Wang W, et al. Review of deep inspiration breath-hold techniques for the treatment of breast cancer. J Med Radiat Sci 2015;62:74–81. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [12].Smyth LM, Knight KA, Aarons YK, et al. The cardiac dose-sparing benefits of deep inspiration breath-hold in left breast irradiation: a systematic review. J Med Radiat Sci 2015;62:66–73. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [13].Hepp R, Ammerpohl M, Morgenstern C, et al. Deep inspiration breath-hold (DIBH) radiotherapy in left-sided breast cancer: dosimetrical comparison and clinical feasibility in 20 patients. Strahlenther Onkol 2015;191:710–6. [DOI] [PubMed] [Google Scholar]
  • [14].Zagar TM, Kaidar-Person O, Tang X, et al. Utility of deep inspiration breath hold for left-sided breast radiation therapy in preventing early cardiac perfusion defects: a prospective study. Int J Radiat Oncol Biol Phys 2017;97:903–9. [DOI] [PubMed] [Google Scholar]
  • [15].Lawler G, Leech M. Dose sparing potential of deep inspiration breath-hold technique for left breast cancer radiotherapy organs-at-risk. Anticancer Res 2017;37:883–90. [DOI] [PubMed] [Google Scholar]
  • [16].Swamy ST, Radha CA, Kathirvel M, et al. Feasibility study of deep inspiration breath-hold based volumetric modulated arc therapy for locally advanced left sided breast cancer patients. Asian Pac J Cancer Prev 2014;15:9033–8. [DOI] [PubMed] [Google Scholar]
  • [17].Wu Z, Xie C, Hu M, et al. Dosimetric benefits of IMRT and VMAT in the treatment of middle thoracic esophageal cancer: is the conformal radiotherapy still an alternative option? J Appl Clin Med Phys 2014;15:93–101. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [18].Pham TT, Ward R, Latty D, et al. Left-sided breast cancer loco-regional radiotherapy with deep inspiration breath-hold: Does volumetric-modulated arc radiotherapy reduce heart dose further compared with tangential intensity-modulated radiotherapy? J Med Imaging Radiat Oncol 2016;60:545–53. [DOI] [PubMed] [Google Scholar]
  • [19].Higby C, Khafaga Y, Al-Shabanah M, et al. Volumetric-modulated arc therapy (VMAT) versus 3D-conformal radiation therapy in supra-diaphragmatic Hodgkin's Lymphoma with mediastinal involvement: a dosimetric comparison. J Egypt Natl Canc Inst 2016;28:163–8. [DOI] [PubMed] [Google Scholar]
  • [20].Briere TM, McAleer MF, Levy LB, et al. Sparing of normal tissues with volumetric arc radiation therapy for glioblastoma: single institution clinical experience. Radiat Oncol 2017;12:79. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [21].Shi J, Yang F, Ju X, et al. Comparative study on dosimetry of VMAT and IMRT in assisted radiotherapy after radical resection of rectal cancer. Oncol Lett 2017;13:2971–4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [22].Xi D, Ding Y, Hu R, et al. Advantages of a technique using two 50 degree arcs in simultaneous integrated boost radiotherapy for left-sidebreast cancer. Sci Rep 2017;7:14748. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [23].Munshi A, Sarkar B, Anbazhagan S, et al. Short tangential arcs in VMAT based breast and chest wall radiotherapy lead to conformity of the breast dose with lesser cardiac and lung doses: a prospective study of breast conservation and mastectomy patients. Australas Phys Eng Sci Med 2017;40:729–36. [DOI] [PubMed] [Google Scholar]
  • [24].Virén T, Heikkilä J, Myllyoja K, et al. Tangential volumetric modulated arc therapy technique for left-sided breast cancer radiotherapy. Radiat Oncol 2015;10:79. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [25].Koivumaki T, Fogliata A, Zeverino M, et al. Dosimetric evaluation of modern radiation therapy techniques for left breast in deep-inspiration breath-hold. Phys Med 2018;45:82–7. [DOI] [PubMed] [Google Scholar]
  • [26].Lazzari G, Terlizzi A, Leo MG, et al. VMAT radiation-induced nausea and vomiting in adjuvant breast cancer radiotherapy: the incidental effect of low-dose bath exposure. Clin Transl Radiat Oncol 2017;7:43–8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [27].Chao PJ, Lee HF, Lan JH, et al. Propensity-score-matched evaluation of the incidence of radiation pneumonitis and secondary cancer risk for breast cancer patients treated with IMRT/VMAT. Sci Rep 2017;7:13771. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [28].Yeung R, Conroy L, Long K, et al. Cardiac dose reduction with deep inspiration breath hold for left-sided breast cancer radiotherapy patients with and without regional nodal irradiation. Radiat Oncol 2015;10:200. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [29].Hanley J, Debois MM, Mah D, et al. Deep inspiration breath-hold technique for lung tumors: the potential value of target immobilization and reduced lung density in dose escalation. Int J Radiat Oncol Biol Phys 1999;45:603–11. [DOI] [PubMed] [Google Scholar]
  • [30].Sixel KE, Aznar MC, Ung YC. Deep inspiration breath hold to reduce irradiated heart volume in breast cancer patients. Int J Radiat Oncol Biol Phys 2001;49:199–204. [DOI] [PubMed] [Google Scholar]
  • [31].Conway JL, Conroy L, Harper L, et al. Deep inspiration breath-hold produces a clinically meaningful reduction in ipsilateral lung dose during locoregional radiation therapy for some women with right-sided breast cancer. Pract Radiat Oncol 2017;7:147–53. [DOI] [PubMed] [Google Scholar]
  • [32].Essers M, Poortmans PM, Verschueren K, et al. Should breathing adapted radiotherapy also be applied for right-sided breast irradiation? Acta Oncologica 2016;55:460–5. [DOI] [PubMed] [Google Scholar]
  • [33].Wiant D, Wentworth S, Liu H, et al. How important is a reproducible breath hold for deep inspiration breath hold breast radiation therapy? Int J Radiat Oncol Biol Phys 2015;93:901–7. [DOI] [PubMed] [Google Scholar]

Articles from Medicine are provided here courtesy of Wolters Kluwer Health

RESOURCES