Comparison of VMAT, IMRT, and 3DCRT radiotherapy techniques in the treatment of synchronous bilateral breast cancer patients

Abstract

Purpose: Synchronous bilateral irradiation of both the mammary glands and the chest wall is a challenging task due to technical difficulties and limited evidence supporting an optimal technique for positive treatment outcomes. We analyzed and compared the dosimetry data of three radiotherapy techniques and selected the most effective one.Methods: Three-dimensional conformal radiation treatment (3DCRT), intensity-modulated radiation therapy (IMRT), and volumetric-modulated arc therapy (VMAT) were compared during the irradiation of synchronous bilateral breast cancer. This was followed by examination of the dose distribution to the target organs (myocardium, left anterior descending artery (LADA), right coronary artery (RCA), and lungs in nine patients.Results: Dose distribution in the lungs was optimal using VMAT, while IMRT was less effective. Doses in the lungs, myocardium, and LADA were highest with 3DCRT. The highest mean dose in the myocardium was observed with IMRT, and a similar effect was noted with RCA. VMAT is the most sparing technique for the myocardium and LADA, despite the RCA dose being slightly higher when compared with that of 3DCRT.Conclusion: We concluded that VMAT is a very effective and satisfactory radiation technique for sparing critical organs. With VMAT, regardless of the volume and side of irradiation, a lower mean dose (Dmean) value was noted in organs at risk such as the myocardium, LADA, and lungs, but not the cardiac conduction system. The use of 3DCRT significantly increases the dose of ionizing radiation reaching the lungs, myocardium, and LADA, which can subsequently cause cardiovascular and lung complications.