Breast Conserving Treatment for Breast Cancer: Dosimetric Comparison of Sequential versus Simultaneous Integrated Photon Boost

[摘要] Background. Breast conserving surgery followed by whole breast irradiation is widely accepted asstandard of care for early breast cancer. Addition of a boost dose to the initial tumor area further reduces local recurrences. We investigated the dosimetric benefits of a simultaneously integrated boost (SIB) compared to a sequential boost to hypofractionate the boost volume, while maintaining normofractionation on the breast.Methods. For 10 patients 4 treatment plans were deployed, 1 with a sequential photon boost, and 3 with different SIB techniques: on a conventional linear accelerator, helical TomoTherapy, and static TomoDirect. Dosimetric comparison was performed.Results. PTV-coverage was good in all techniques. Conformity was better with all SIB techniques compared to sequential boost (P= 0.0001). There was less dose spilling to the ipsilateral breast outside the PTVboost (P= 0.04). The dose to the organs at risk (OAR) was not influenced by SIB compared to sequential boost. Helical TomoTherapy showed a higher mean dose to the contralateral breast, but less than 5 Gy for each patient.Conclusions. SIB showed less dose spilling within the breast and equal dose to OAR compared to sequential boost.Both helical TomoTherapy andthe conventional technique delivered acceptable dosimetry. SIB seems a safe alternative and can be implemented in clinical routine.

[学科分类] 基础医学