Treatment Results and Dosimetric Comparison of Synchronous Bilateral Breast Cancer with Helical Tomotherapy and Volumetric-Modulated Arc Radiotherapy

Radiotherapy in Bilateral Breast Cancer

Abstract

Objective: The aim of this study is to present the short-term treatment results and dosimetric comparison of patients with synchronous bilateral breast cancer (SBBC) with helical tomotherapy (HT) and volumetric-modulated arc therapy (VMAT)  by virtual treatment plans.

Material and Methods: Twelve patients with SBBC who were diagnosed between June 2015 and June 2018, received adjuvant bilateral breast or chest wall RT were retrospectively analyzed. Seven of the patients were irradiated in helical Tomotherapy (Hi-Art ® Version 5.1.3) (HT) and the remaining 5 patients in Elekta Versa-HD v4.0 with VMAT. HT and VMAT plans were compared based on dose-volume histograms (DVH).

Results: The median follow-up period of the patients was 19 months (range, 3-37 months). Nine (75%) patients had a locally advanced stage. Neoadjuvant chemotherapy was applied to 5 (41.6%) patients. One of 12 SBBC patients died due to systemic progression. Local control was achieved in other patients. Acute grade 1-2 dysphagia was observed in 5 and acute grade 1-2 radiodermatitis in 7 cases. When comparing VMAT and HT plans, statistically significant difference was revealed only in PTV D_min and Lung V₅ values.  Lung V₅ was found statistically better in favor of helical tomotherapy (HT) and PTV D_min in favor of Elekta Versa-VMAT.

Conclusion: Various RT techniques as VMAT and helical tomotherapy can be approached in the management of rare cancers such as SBBC, and the patient-specific optimal plan should be selected.