Three-dimensional conformal versus intensity modulated radiotherapy in breast cancer treatment: is necessary a medical reversal?

Objectives: Aim of the present study is to compare three-dimensional conformal RT (3D-CRT) and 4-fields intensity modulated radiation therapy (4f-IMRT) treatment plans, in terms of target dose coverage, integral dose and dose to Organs at risk (OARs) in early breast cancer (BC).

Methods: Twenty consecutive BC patients, after lumpectomy, were selected for the present analysis. A total dose of 50 Gy and a simultaneous dose of 60 Gy in 25 fractions was prescribed to Planning Target Volume of the whole breast (PTV_breast) and of the surgical bed, respectively. For each patient, a 3D-CRT plan and a sliding-window 4f-IMRT plan were generated. Conformity and homogeneity indexes (CI, HI) and various organ specific V_xGy values were analyzed for PTVs, OARs and normal tissue (NT), respectively.

Results: In terms of HI, 4f-IMRT was superior to 3D-CRT for the PTV_breast (p < 0.0001), and a significant difference for CI was observed in favor of 4f-IMRT (p < 0.0001).In terms of dose to OARs, a superiority of 4f-IMRT was shown. For NT, all parameters are in favor of IMRT, except the V _5Gy for which the difference was not statistically significant. The average NT-D_mean was 2.7 ± 0.7 for 3D-CRT and 1.8 ± 0.5 for 4f-IMRT (p < 0.0001).

Conclusions: 4f-IMRT technique significantly reduced the dose to OARs and NT, with a better target coverage compared to 3D-CRT.