01.12.2017 | Research | Ausgabe 1/2017 Open Access

# Intentional avoidance of the esophagus using intensity modulated radiation therapy to reduce dysphagia after palliative thoracic radiation

- Zeitschrift:
- Radiation Oncology > Ausgabe 1/2017

## Background

_{10}) were associated with a modest improvement in overall survival, but at the cost of increased rates of dysphagia [1]. These RCTs were conducted in an era where radiation delivery for these patients was limited to simple beam arrangements, e.g. a parallel-opposed pair (POP).

## Methods

_{ i }is the fractional organ volume receiving a dose D

_{ i }with the equivalent dose given in 2 Gy fractions. Separately, a sensitivity analysis was performed to determine the impact of small changes to the treatment design.

_{ i }, and d

_{ i }represent the number of fractions (i.e. 10), the fractional volume i receiving a discretized dose at I, respectively. The alpha-beta ratio (α/β) used in the NTD calculation was 10, while an α/β of 3 was used for all normal tissue calculations. Dose volume histograms were exported and read using Matlab (R2012b, Mathworks, MA) where dosimetric parameters such as the mean dose to the esophagus and lung were determined. Comparisons were made using the Wilcoxon matched pair signed rank test. All statistical analyses were performed using SAS software (versions 9.3, SAS institute, CARY, USA), using two-sided statistical testing at the 0.05 significance level.

## Results

^{2}, while the average length of the esophagus contained within the field (D50) was 12 ± 3 cm.

Parameter | Parallel-opposed pair plan | ES-IMRT esophagus sparing plan |
---|---|---|

D99 (GTV) | 28.0 ± 1.0 Gy | 24.7 ± 1.4 Gy |

D95 (GTV) | 28.9 ± 8.8 Gy | 28.8 ± 4.8 Gy |

D5 (GTV) | 34.0 ± 14 Gy | 32.9 ± 7.4 Gy |

D99 (PTV) | 26.5 ± 2.5 Gy | 22.0 ± 0.8 Gy |

D95 (PTV) | 28.1 ± 4.6 Gy | 25.9 ± 3.6 Gy |

D5 (PTV) | 33.8 ± 12 Gy | 32.7 ± 4.4 Gy |