Isocenter bilateral tangential fields combined with intensity-modulated radiotherapy for synchronous bilateral whole breast irradiation / 中华放射肿瘤学杂志

ABSTRACT

Objective To investigate the dose characteristics and outcomes of a single isocenter bilateral tangential fields (IBTF) combined with intensity-modulated radiotherapy (IMRT) in bilateral breast radiotherapy (BBR).Methods Fourteen female patients with synchronous bilateral breast cancer (SBBC) after breast-conserving surgery (BCS) were enrolled in this study.All patients received BBR using IBTF combined with IMRT at a conventional (50 Gy/25f) or hypofractionated (43.5 Gy/15f) dose.For patients with invasive cancer,the additional tumor bed boost was given with sequential electron radiation or simultaneously photon IMRT.The coverage,uniformity and short-term clinical efficacy were evaluated.Results The number of the irradiation field was 8-11,including 4-7 intensity-modulated fields.The bilateral breast PTV dose coverage reached 95％ in all plans.For the tumor bed,the mean dose coverage was (95.54± 1.33) ％ (left) and (94.19± 1.03) ％(right) using photon,and (90.25± 8.79) ％ (left) and (85.28± 8.35) ％(right) using electron.The average V20 of bilateral lungs was (16.69±3.90)％.The cardiac Dmean was 5.48 Gy.Three patients presented with grade Ⅱ acute skin toxicities.No ≥ grade Ⅱ pneumonitis was observed.No recurrence occurred with the median follow-up time of 30.1 months.Eleven patients showed excellent cosmetic results.Conclusion BBR using IBTF combined with IMRT is efficacious and safe for patients with SBBC after BCS.