Volumetric modulated arc therapy applied to synchronous bilateral breast cancer radiotherapy: dosimetric study on deep inspiration breath hold versus free breathing set up

Abstract

Aim. The purpose of this planning report is to compare dosimetric results of deep inspiration breath hold (DIBH) and free breathing (FB) set up in patients with synchronous bilateral breast cancer (SBBC) treated with adjuvant radiotherapy. Material and methods. Fourteen patients with early stage bilateral breast cancer were treated with breast conservative surgery. Bilateral breast planning treatment volume (PTV) and organs at risk (OARs) were delineated for DIBH and FB datasets on the planning computed tomography (CT). Volumetric modulated arc therapy (VMAT/RapidArc ®) plans were generated in the two set up modalities. During plan optimization the objectives were to obtain comparable target coverage, dose conformity and homogeneity with an acceptable dose levels for OARs: both lungs, heart, left anterior descending coronary artery (LAD) and thyroid. Results. The maximum and the mean dose to the heart were reduced in DIBH modality with an average of 19.2 Gy and 6.5 Gy versus 25.9 Gy and 8 Gy in FB. The mean dose to the sum of lungs was 13.3 Gy in DIBH modality versus 14.3 Gy in FB. We observed a better sparing of LAD in DIBH with a maximum dose of 14.5 Gy versus 18 Gy in FB modality. Conclusions. DIBH allows a better sparing of heart and LAD compared to FB modality; it provides better results in term of mean dose to the sum of lungs. The clinical impact on acute and late toxicity is under investigation.

Intensity Modulated Proton Therapy for Bilateral Breast or Chest Wall and Comprehensive Nodal Irradiation for Synchronous Bilateral Breast Cancer: Initial Clinical Experience and Dosimetric Comparison

“… 5 , 6 , 8 , 9 , 10 , 13 Respiratory management with DIBH or respiratory gating also reduces the dose to the heart and lungs. 11 Two clinical series of adjuvant photon radiation therapy for SBBC reported good oncologic outcomes and low rates of radiation-associated lung toxic effects. Twenty-one patients were treated with tomotherapy and assessed with pulmonary function tests and high-resolution CT scans.…”

“…We selected VMAT as a gold standard comparison to IMPT in this study because multiple planning studies have shown that VMAT and hybrid techniques achieve superior normal tissue avoidance compared to 3D techniques 5,6,[8][9][10]13 . Respiratory management with DIBH or respiratory gating also reduces dose to the heart and lungs 11 . Two clinical series of adjuvant photon radiotherapy for SBBC reported good oncologic outcomes and low rates of radiation-associated lung toxicity.…”

“…Bilateral irradiation poses a particular treatment challenge, especially if internal mammary lymph nodes (IMN) are targeted, due to competing goals of target coverage and normal tissue sparing. There is relatively little published regarding treatment of these complex cases, mostly limited to case reports and dosimetric studies [4][5][6][7][8][9][10][11][12][13][14][15] . Proton beam therapy (PBT) is emerging as a promising treatment modality in patients with indications for regional nodal irradiation (RNI), especially in those with unfavorable anatomy, such as pectus excavatum or small lung volume, as PBT reduces dose to adjacent normal tissues including the heart and lungs [16][17][18][19][20] .…”

“…There is relatively little research published regarding treatment of these complex cases, mostly limited to case reports and dosimetric studies. 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 Proton beam therapy (PBT) is emerging as a promising treatment modality in patients with indications for regional nodal irradiation, especially in those with unfavorable anatomy such as pectus excavatum or small lung volume, because PBT reduces the dose to adjacent normal tissues including the heart and lungs. 16 , 17 , 18 , 19 , 20 Increased doses to these critical structures are associated with increased risks for late cardiopulmonary toxic effects and secondary cancers.…”

Hypofractionated Hybrid Radiotherapy Techniques for Synchronous Bilateral Breast Cancer

“…The present study also showed a similar trend with 3DCRT+IMRT and 3DCRT+VMAT hybrid plans. Subramanian et al, (2016) Gaudino et al, (2018) compared VMAT to SBBC RT in deep inspiration breath-hold (DIBH) versus free-breathing set up. While it was reported that the DIBH method can able to reduce the dose to the heart, LAD, and lungs, this practice might not be achievable for all patients.…”