Radiotherapy instead of axillary lymph node dissection: evaluation of axillary lymph node dose coverage with whole breast radiotherapy.
Rep Pract Oncol Radiother 2022;
27:458-466. [PMID:
36186703 PMCID:
PMC9518762 DOI:
10.5603/rpor.a2022.0043]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/24/2022] [Indexed: 11/25/2022] Open
Abstract
Background
The purpose of this study was to investigate the dose coverage of sentinel lymph nodes (SLN), level I, II and III axillary volumes from tangent fields for breast cancer patients with positive SLN without axillary dissection.
Materials and methods
In 30 patients with cN0 invasive breast cancer treated with breast conserving surgery and SLN biopsy, the SLN area was intraoperatively marked with a titanium clip. Retrospectively, the SLN area and axillary target volumes were contoured, and three plans [standard tangent fields (STgF), high tangent fields (HTgF), and STgF + axillary-supraclavicular field] were generated for each patient. The prescribed dose was standardized to 50 Gy in 2 Gy fractions to the isocenter.
Results
The mean dose with STgF or HTgF was 33.1 and 49.1 Gy (p = 0.0001) in the SLN area, 25.7 and 45.1 Gy (p < 0.0001) in the volume of level I, 7.2 and 28.9 Gy (p < 0.0001) in the level II and 3.5 and 12.7 Gy (p = 0.0003) in the level III. Adequate therapeutic doses to the level II or III volumes were delivered only with STgF + axillary-supraclavicular field. The mean dose of ipsilateral lung was the highest with the three-field-technique, 9.9 Gy. SLN area, level I, II or III were completely included in the HTgF with 93.3%, 73.3%, 13.3% and 0%, respectively.
Conclusions
SLN area should be marked by surgical clip and axillary target volumes should be contoured to obtain accurate dose estimations. The use of HTgF improve axillary coverage.
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