Whole‐breast irradiation with lumpectomy cavity boost and regional nodal irradiation: Dosimetric comparison of 3D‐CRT using sequential boost and dual partial‐arc VMAT using simultaneous integrated boost

Abstract Objective To compare volumetric modulated arc therapy (VMAT) with simultaneous tumor bed boost (dpSIB‐VMAT) to the whole breast and regional nodal irradiation (RNI) against standard three‐dimensional conformal radiotherapy plus RNI sequential (3D‐CRT‐seqB). Methods Thirty patients who underwent cancer surgery (BCS) axillary lymph node dissection (ALND) were enrolled. Two plans generated for each case: (1) dpSIB‐VMAT, (2) 3D‐CRT‐seqB plans. Planning target volume (PTV)‐Breast PTV‐Nodes prescribed at a dose of 50 Gy in 25 fractions both PTV‐Boost was 60 simultaneously dpSIB‐VMAT plans, whereas it planned sequentially 10 5 fractions. Dosimetric parameters compared between two Results Both achieved coverage. D mean heart lower left‐sided cases (7.17 ± 0.66 vs. 10.12 2.91 Gy; t = 4.02; p 0.001). Ipsilateral lung (15.87 1.40 19.82 3.20 6.30; <0.001) significantly but doses contralateral (4.30 1.76 1.48 0.76 ‐7.84; <0.001), (3.86 1.21 0.96 0.25 ‐13.13; esophagus (13.11 2.63 10.32 3.56 ‐6.65; relatively higher dpSIB‐VMAT. Conclusion Dosimetrically, reduced ipsilateral (in left not right cases) adequate