Breast-Conserving Radiotherapy with Simultaneous Integrated Boost—A Dosimetric Comparison of 3DCRT, VMAT and IMRT: Do We Really have a Better Plan?

Abstract

The availability of more advanced technology like hypo-fractionation has the potential of being the new standard of care in breast cancer. This study evaluates whether 3DCRT with a field-in-field technique (FIF) and a simultaneous integrated boost (SIB) could provide a dosimetrically comparable plan delivered to VMAT or IMRT. 3DCRT-FIF-SIB, VMAT and IMRT-SIB plans were generated for 20 patients. The plans were compared for planning target volume coverage (PTV 95), homogeneity and conformity, dose delivered to lungs, heart and C/L breast. 3DCRT FIF provided better sparing of C/L breast V1 and V5, whole lung V5, p = 0.000. The VMAT plans spared heart V30: (0.1 ± 0.46 vs. 11.5 ± 18.3) p = 0.000 and I/L lung V20: (19.3 ± 5 vs. 32.2 ± 11.1) p = 0.000. It provided a better coverage V95: (97 ± 0.8 vs. 95 ± 2.9) p = 0.002 and sparing of the heart V30: (0.1 ± 0.5 vs. 8.6 ± 11.5) p < 0.002 and lungs I/L V20: (19.3 ± 5.0 vs. 30.7 ± 6.1) p = 0.000. The treatment was faster with less exposure in terms of MU: (529 ± 57.8 vs. 1024 ± 298) p = 0.000. 3DCRT provides a dosimetrically acceptable alternative to more advanced technologies. VMAT and IMRT provide better sparing of heart and lungs. VMAT has a slight benefit of conformity, reduced exposure and shorter treatment time.