Immobilization-assisted abdominal deep inspiration breath-hold in post-mastectomy radiotherapy of left-sided breast cancer with internal mammary chain coverage

Abstract

Background: Whether to prophylactically irradiate the ipsilateral internal mammary chain (IMC) in postmastectomy radiotherapy (PMRT) remains controversial because of equivocal clinical benefits against the added toxicities. Our previous study revealed that the cardiac dose was decreased during left-sided breast radiotherapy with abdominal deep inspiration breath-hold (aDIBH) as compared with free-breathing (FB) and thoracic deep inspiration breath-hold (tDIBH). Here we present the dosimetric advantage of aDIBH for patients undergoing PMRT with IMC coverage.Methods: We prospectively analyzed 19 patients with left-sided breast cancer who underwent PMRT.Patients underwent computed tomography (CT) simulation under both free-breathing (FB) and aDIBH.The heart, left anterior descending coronary artery (LAD), lungs, and the contralateral breast was defined as organs at risk (OARs). Three-dimensional conformal radiation therapy (3D-CRT), inverse planning intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT) were used to calculate the doses received by both the planning target volume (PTV) and OARs, which were compared using the Wilcoxon signed-rank test.Results: Compared with FB, the D mean of the heart and LAD were respectively reduced by 3.5 Gy (P<0.003) and 8.9 Gy (P<0.001) in 3D-CRT, 2.6 Gy (P<0.001), and 7.8 Gy (P=0.001) in IMRT, 1.5 Gy (P<0.001) and 4.5 Gy (P=0.001) in VMAT plans under aDIBH. Among all these plans, the D mean of the heart was lowest in aDIBH IMRT and 1.3 Gy lower than in aDIBH VMAT (P=0.002). aDIBH IMRT also resulted in a significantly reduced dose to the ipsilateral lung than plans under FB (P<0.05). D mean and V5 to the contralateral lung and breast were higher in VMAT plans (P<0.05).Conclusions: Using an immobilization-assisted aDIBH technique, radiation doses to the heart can be kept at reasonably low levels even if IMC is included in the clinical target volume (CTV). Among 3D-CRT, IMRT, and VMAT plans, IMRT plus aDIBH results in the best heart-sparing effect. We recommend that the aDIBH technique be routinely applied in suitable patients if the IMC is irradiated.

Optimal radiotherapy modality sparing for cardiac valves in left-sided breast cancer

“…However, radiotherapy is associated with long-term cardiac toxicity and in long-term breast cancer survivors, cardiovascular disease after radiation therapy has become the leading cause of non-breast cancer death ( 3 , 4 ). Patients with left-sided breast cancer who underwent adjuvant radiotherapy may have experienced clinically significant cardiac radiation exposure ( 5 ) and may be at higher risk of these cardiac complications than patients with right-sided breast cancer. Therefore, the cardiotoxicity caused by radiotherapy in left-sided breast cancer is an important problem that needs to be studied extensively.…”

Analysis of deep inspiration breath-hold technique to improve dosimetric and clinical advantages in postoperative intensity-modulated radiation therapy for thymomas

“…Training patients with deep inspiration breath-hold (DIBH) has been identified as a successful method to decrease the internal target volume (ITV) by controlling tumor movement, and, in turn, minimizing the volume of lung tissue included in the treatment fields and the administered dose. This method is effective and can be applied to various thoracic tumors (5)(6)(7)(8)(9). To the best of our knowledge, this is the first study to compare dosimetric parameters for thymoma patients receiving postoperative radiation therapy during two respiratory states (FB and DIBH).…”