Dosimetric assessment of left anterior descending, heart and brachial plexus in breast cancer patients irradiated with helical tomotherapy

Background:In this study, it was aimed to evaluate the radiation doses to the heart and uncommon critical organs such as left anterior descending (LAD) and brachial plexus (BP), in breast cancer patients irradiated with tomotherapy.Methods and Materials: Eighty patients with primary breast cancer received whole breast and supraclavicular region radiotherapy (RT) with helical tomotherapy were evaluated.The patients were divided into 4 groups according to the surgical procedure performed right mastectomy (RM-Group 1), left mastectomy (LM-Group 2), right breastconserving surgery (R-BCS) (Group 3), and left breast-conserving surgery (L-BCS-Group 4).The homogeneity index (HI) for target volume, total volume (V), maximum doses (Dmax), and mean doses (Dmean) for LAD and ipsilateral BP and V, Dmean, V5 (volume of received 5 Gy) and V25 (volume of received 25 Gy) were determined for the heart to all groups.Results: According to the results, HI's were almost the same in all groups (~1.08).Although the dosimetric parameters for the heart were higher in the left breast irradiations there was a statistical difference between the groups.Dosimetric parameters of LAD are also similar to cardiac dose.However, the increase in the left breast is more pronounced.The brachial plexus dose parameters of all groups were close to each other.Conclusion: It is recommended that the brachial plexus dose should be included in routine dosimetric evaluation in terms of minimizing the risk of radiation-induced plexopathy.Also, the LAD dose should be evaluated with the heart dose to reduce the cardiotoxic effects that may occur after radiotherapy.