The Effect of Internal Mammary Chain Radiotherapy After Post-Mastectomy on Coronary Arteries and Chambers of Heart: Dosimetric Comparison of Tangential Field FIF and d-IMRT Plans
Gülhan GÜLER AVCI1,Halis BOZKURT1,Mustafa BAŞAK2,Yıldız GÜNEY3,Muzaffer Bedri ALTUNDAĞ4
1Department of Radiation Oncology, Tokat Gaziosmanpaşa University Faculty of Medicine, Tokat-Türkiye
2Department of Medical Oncology, Tokat Gaziosmanpaşa University Faculty of Medicine, Tokat-Türkiye
3Department of Radiation Oncology, Ankara Memorial Hospital, Ankara-Türkiye
4Department of Radiation Oncology, Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital, Ankara-Türkiye
DOI : 10.5505/tjo.2022.3504 OBJECTIVE
The aim of this study was to compare tangential field field-in-field (FIF) and dynamic-intensity-modulated radiotherapy (d-IMRT) techniques in terms of changes in cardiac substructure and coronary arteries doses on dose-volume histogram (DVH).

Fifteen patients with the left breast cancer who received radiotherapy to the chest wall (CW) were retrospectively selected. The left main coronary artery, left anterior descending (LAD), circumflex and right coronary arteries, and heart chambers were contoured. Dmean, V5, V10, and V30 for heart chambers; Dmean and Dmax for coronary vessels; and Dmean, V95, V107, CI and HI for planned target volume were compared between plans on DVH.

When the internal mammary lymph node (IMLN) field is added to the CW, high-dose volumes of the whole heart and ventricles (V30) and LAD doses are significantly better protected with d-IMRT technique (whole heart V30: 9.4% by 6.2%, ventricle L V30: 17.1% by 9.9%, ventricle R V30: 7.3% by 4.3%, and LAD Dmax: 52.7 Gy by 51 Gy). All the low-dose volumes of the whole heart and ventricles (V5 and V10) and all coronary vessels excepting LAD were better protected in the FIF technique.

In patients who will undergo IMLN radiotherapy, especially if they have coronary disease, RT technique can be selected according to the vessel where the damage is located. However, more research is warranted on this subject. Keywords : Coronary vessels; heart protection; heart substructure; internal mammary chain radiotherapy; left anterior descending; left breast cancer