Radiat Oncol J.  2018 Mar;36(1):63-70. 10.3857/roj.2017.00241.

Dosimetric comparison between modulated arc therapy and static intensity modulated radiotherapy in thoracic esophageal cancer: a single institutional experience

• Choi KH
• Kim J
• Lee SW
• Kang YN
• Jang H

• KMID: 2418886
• DOI: http://doi.org/10.3857/roj.2017.00241

Abstract

PURPOSE
The objective of this study was to compare dosimetric characteristics of three-dimensional conformal radiotherapy (3D-CRT) and two types of intensity-modulated radiotherapy (IMRT) which are step-and-shoot intensity modulated radiotherapy (s-IMRT) and modulated arc therapy (mARC) for thoracic esophageal cancer and analyze whether IMRT could reduce organ-at-risk (OAR) dose.
MATERIALS AND METHODS
We performed 3D-CRT, s-IMRT, and mARC planning for ten patients with thoracic esophageal cancer. The dose-volume histogram for each plan was extracted and the mean dose and clinically significant parameters were analyzed.
RESULTS
Analysis of target coverage showed that the conformity index (CI) and conformation number (CN) in mARC were superior to the other two plans (CI, p = 0.050; CN, p = 0.042). For the comparison of OAR, lung V5 was lowest in s-IMRT, followed by 3D-CRT, and mARC (p = 0.033). s-IMRT and mARC had lower values than 3D-CRT for heart V30 (p = 0.039), V40 (p = 0.040), and V50 (p = 0.032).
CONCLUSION
Effective conservation of the lung and heart in thoracic esophageal cancer could be expected when using s-IMRT. The mARC was lower in lung V10, V20, and V30 than in 3D-CRT, but could not be proven superior in lung V5. In conclusion, low-dose exposure to the lung and heart were expected to be lower in s-IMRT, reducing complications such as radiation pneumonitis or heart-related toxicities.

Keyword

Esophagus cancer; Intensity-modulated radiotherapy; Modulated arc (mARC) technique; Dosimetric comparison

MeSH Terms

Esophageal Neoplasms*
Heart
Humans
Lung
Radiation Pneumonitis
Radiotherapy*
Radiotherapy, Conformal
Radiotherapy, Intensity-Modulated