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SU‐E‐P‐56: Dosimetric Comparison of Three Post Modified Radical Mastectomy Radiotherapy Techniques for Locally Advanced Left‐Sided Breast Cancer and Beyond
Author(s) -
Ma C,
Zhang W,
Lu J,
Wu L,
Wu F,
Huang B,
Li D
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4923990
Subject(s) - medicine , radiation therapy , dosimetry , nuclear medicine , breast cancer , significant difference , modified radical mastectomy , mastectomy , cancer , radiology
Purpose: To compare the dosimetry of post modified radical mastectomy radiotherapy (PMRMRT) for left‐sided breast cancer using 3‐dimensional conformal radiotherapy (3DCRT), intensity‐modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Methods: We created ten sets of PMRMRT plans for ten consecutive patients and utilized two tangential and one or two supraclavicular beams in 3DCRT, a total of 5 beams in IMRT and two optimized partial arcs in VMAT. The difference in results between any two of the three new plans, between new and previous 3DCRT plans were compared and analyzed by ANOVA (α =0.05) and paired‐sample t‐test respectively. P values less than 0.05 were considered statistically significant. Results: Both IMRT and VMAT plans had similar PTV coverage, hotspot area and conformity (all p>0.05), and significantly higher PTV coverage compared with new 3DCRT (both p<0.001). IMRT plans had significantly less heart and left lung radiation exposure compared with VMAT (all p<0.05). The 3DCRT plans with larger estimated CTV displacement had better target coverage but worse OARs sparing compared to those with smaller one. Conclusion: IMRT has dosimetrical advantages over the other two techniques in PMRMRT for left‐sided breast cancer. Individually quantifying and minimizing CTV displacement can significantly improve dosage distribution. This work was supported by the Medical Scientific Research Foundation of Guangdong Procvince (A2014455 to Changchun Ma)