Open AccessDosimetric comparison of incidental radiation to the internal mammary nodes after breast-conserving surgery using 3 techniques-inverse intensity-modulated radiotherapy, field-in-field intensity-modulated radiotherapy, and 3-dimensional conformal radiotherapy
Author(s) -
Yiying Song,
Ting Yu,
Wei Wang,
Jianbin Li,
Tao Sun,
Pengfei Qiu,
Min Xu,
Qing Shao
Publication year - 2019
Publication title -
medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.59
H-Index - 148
eISSN - 1536-5964
pISSN - 0025-7974
DOI - 10.1097/md.0000000000017549
Subject(s) - medicine , radiation therapy , nuclear medicine , dosimetry , breast conserving surgery , breast cancer , radiology , mastectomy , cancer
Background: The study aimed to evaluate and compare the dosimetric parameters of incidental irradiation to internal mammary node (IMN) from inverse intensity-modulated radiotherapy (I-IMRT) and field-in-field IMRT (F-IMRT), and 3-dimensional conformal radiotherapy (3D-CRT) in patients after breast-conservation surgery (BCS). Methods: Eighty-four patients with BCS were selected. The breast, tumor bed, and IMN, including intercostal spaces (ICS) 1 to 3, were contoured. Three plans were generated. The prescription doses for the breast and tumor bed were 50.4 Gy/28 F and 60.2 Gy/28 F, respectively. If there was no tumor bed boost, patient was treated with 50 Gy/25 F for the whole breast only. The IMN was not included in planning target volume. Results: The median mean dose (D mean ) of the IMN total (ICS 1–3) was 2740.2 cGy, 2973.9 cGy, and 2951.4 cGy for I-IMRT, F-IMRT, and 3D-CRT, respectively. Differences were not detected between any of the plans. After separating ICS 1 to 3 for further analysis, neither of the D mean of ICS 1 to 2 was significantly different between the plans. However, for ICS 3, the median D mean was highest for I-IMRT, and those for 3D-CRT and F-IMRT were not significantly different. After separating the 3 techniques for further analysis, the median D mean was highest in ICS 3 and lowest in ICS 1 for all the 3 techniques. Conclusion: All 3 techniques failed to attain an adequate dose to cure subclinical disease, and there were no significant differences among the 3 techniques. It is risky to avoid IMN irradiation (IMNI) using any of the 3 techniques during whole-breast radiotherapy in women with indications for elective IMNI. However, in era of systematic therapy, whether the incidental dose could meet clinical acquirements needs further follow-up.