Evaluation of optimal treatment planning for radiotherapy of synchronous bilateral breast cancer including regional lymph node irradiation.

ABSTRACT: BACKGROUND:We evaluated the optimal radiotherapy (RT) plan for synchronous bilateral breast cancer (SBBC), especially treatment plans including the regional lymph node (LN) area. METHODS:This study was conducted using 15 patients with SBBC (5 with small breasts, 5 with large breasts, and 5 who underwent a left total mastectomy). The clinical target volume (CTV) was defined as the volume enveloping the bilateral whole breasts/chest wall and left regional LN area. We established the following plans: 1) volumetric-modulated arc therapy (VMAT)-the only plan using two pairs of partial arcs for the whole target volume, 2) VMAT using one partial arc for the left CTV followed by a 3D tangential technique for the right breast (primary hybrid plan), and 3) VMAT for the left CTV followed by a tangential technique using an automatically calculated prescription dose for the right breast, considering the background dose from the left breast VMAT plan (modified hybrid plan). The Tukey test and one-way analysis of variance were used to compare the target coverage and doses to organs at risk (OARs) of the three techniques. RESULTS:For target coverage, the VMAT-only and modified hybrid plans showed comparable target coverage in terms of Dmean (50.33?Gy vs. 50.53?Gy, p?=?0.106). The primary hybrid plan showed the largest distribution of the high-dose volume, with V105% of 25.69% and V110% of 6.37% for the planning target volume (PTV) (p?

SUBMITTER: Cho Y 

PROVIDER: S-EPMC6444509 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature