Dosimetric and Radiobiological Comparison of Five Techniques for Postmastectomy Radiotherapy with Simultaneous Integrated Boost

Du Tang; Zhan Liang; Fada Guan; Zhen Yang

doi:10.1155/2020/9097352

Dosimetric and Radiobiological Comparison of Five Techniques for Postmastectomy Radiotherapy with Simultaneous Integrated Boost

Biomed Res Int. 2020 Jul 21:2020:9097352. doi: 10.1155/2020/9097352. eCollection 2020.

Authors

Du Tang¹, Zhan Liang¹, Fada Guan², Zhen Yang¹

Affiliations

¹ Department of Oncology, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
² Department of Radiation Physics, Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.

Abstract

Purpose: To compare five techniques for the postmastectomy radiotherapy (PMRT) with simultaneous integrated boost (SIB).

Materials and methods: Twenty patients with left-sided breast cancer were retrospectively selected. Five treatment plans were created for each patient: TomoDirect (TD), unblocked helical TomoTherapy (unb-HT), blocked HT (b-HT), hybrid intensity-modulated radiotherapy (hy-IMRT), and fixed-field IMRT (ff-IMRT). A dose of 50.4 Gy in 28 fractions to PTV_total and 60.2 Gy in 28 fractions to PTV_boost were prescribed. The dosimetric parameters for targets and organs at risk (OARs), the normal tissue complication probability (NTCP), the second cancer complication probability (SCCP) for OARs, and the treatment efficiency were assessed and compared.

Results: TD plans and hy-IMRT plans had similar good dose coverage and homogeneity for both PTV_boost and PTV_total and superior dose sparing for the lungs and heart. The ff-IMRT plans had similar dosimetric results for the target volumes compared with the TD and hy-IMRT plans, but gave a relatively higher NTCP and SCCP for the lungs. The unb-HT plans exhibited the highest OAR mean dose, highest NTCP for the lungs (0.97 ± 1.25‰) and heart (4.58 ± 3.62%), and highest SCCP for the lungs (3.57 ± 0.05%) and contralateral breast (2.75 ± 0.29%) among all techniques. The b-HT plans significantly outperformed unb-HT plans with respect to the sparing of the lungs and heart. This technique also showed the best conformity index (0.73 ± 0.08) for PTV_boost and the optimal NTCP for the lungs (0.03 ± 0.03‰) and heart (0.61 ± 0.73%). Concerning the delivery efficiency, the hy-IMRT and ff-IMRT achieved much higher delivery efficiency compared with TomoTherapy plans.

Conclusion: Of the five techniques studied, TD and hy-IMRT are considered the preferable options for PMRT with SIB for left-sided breast cancer treatment and can be routinely applied in clinical practice.

MeSH terms

Adult
Aged
Breast Neoplasms / therapy*
Female
Humans
Mastectomy*
Middle Aged
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted*