Optimizing posterior neck coverage in regional nodal irradiation for breast cancer.
Document Type
Article
Publication Date
4-29-2025
Publication Title
Medical dosimetry : official journal of the American Association of Medical Dosimetrists
Abstract
Patterns-of-failure studies suggest the posterior neck (PN) may harbor microscopic disease in patients with locally advanced breast cancer. We compared target coverage, lung dosimetry, and toxicity in patients treated with either an anterior oblique field (AO) or opposed oblique fields (OO) to address the superior axillary and supraclavicular (SCV) nodal regions. We identified 109 patients treated at a single institution with regional nodal irradiation utilizing a mono-isocentric technique with a "third field" for superior axillary and SCV coverage. SCV and PN clinical target volume (CTV) coverage was determined based on the delivered treatment plan. CTV coverage, lung dosimetry, and toxicity differences between AO and OO treatment groups were evaluated using Wilcoxon rank-sum and Fisher's exact tests. The AO group had 29 patients, and the OO group had 80. Both groups had similar body mass indices and anterior-posterior separations at the match line. The median V90% of the PN was significantly improved in the OO group (100%) compared to 30% in the AO group (p < 0.001). The median V90% in the axillary levels I to III were similarly improved in the OO group compared to the OA group (p < 0.001). The maximum dose, heterogeneity and V90% of the SCV, as well as the lung dosimetry were similar in both groups. Rates of toxicities including ipsilateral upper extremity lymphedema and pneumonitis (all grade 1), and moist desquamation were low and similar across groups. Compared to a single anterior field, opposed oblique fields provide superior axillary and posterior neck coverage without increasing toxicity.
Volume
S0958-3947
Issue
25
First Page
00021-4
Recommended Citation
Oyeniyi JF, Loving BA, Quinn TJ, Almahariq MF, Dilworth JT. Optimizing posterior neck coverage in regional nodal irradiation for breast cancer. Med Dosim. 2025 Apr 29:S0958-3947(25)00021-4. doi: 10.1016/j.meddos.2025.03.005. Epub ahead of print. PMID: 40307069.
DOI
10.1016/j.meddos.2025.03.005.
ISSN
1873-4022
PubMed ID
40307069
