Dose metrics of the brachial plexus in post-mastectomy radiotherapy of breast cancer
Benedict Ian Torno,
Philippines
PO-2330
Abstract
Dose metrics of the brachial plexus in post-mastectomy radiotherapy of breast cancer
Authors: Benedict Ian Torno1, Erika Reyes1
1Perpetual Help Medical Center-Las Pinas, Radiation Oncology, Las Pinas, Philippines
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Purpose or Objective
This study aims to establish the brachial plexus as one of the organs at risk (OARs) for breast cancer patients undergoing post-mastectomy locoregional radiotherapy followed by an axillary boost.
Material and Methods
A total of 35 patients undergoing post-mastectomy locoregional radiotherapy were included in this study. Non-contrast Computed Tomography (CT) data sets were retrieved where the brachial plexus was contoured. Following the delineation of the brachial plexus, dose-volume histograms (DVHs) were then generated. From these DVHs, the radiotherapy plan maximum radiation dose (Dmax), brachial plexus Dmax, brachial plexus mean dose, and volume of the brachial plexus receiving at least 40 Gy (V40) was then recorded.
Results
From the data gathered, the brachial plexus overall mean Dmax was above the minimum dose constraint with a value of 61.74 Gy (SD=5.0) and its highest value being 73.42 Gy suggesting a high risk of radiation-induced brachial plexopathy. However, the mean V40 value of the brachial plexus was 6.42 cc (SD=1.62) ranging from 4.08 to 11.03 which was below the proposed value to be associated with an increased risk of paresthesia.
Conclusion
This study recommends contouring of the brachial plexus as one of OARs for breast cancer patients undergoing post-mastectomy locoregional radiotherapy followed by an axillary boost.