Evaluation of three APBI techniques under NSABP B-39 guidelines

Area of Science:

• Oncology
• Radiation Oncology
• Medical Physics

Background:

• Accelerated partial breast irradiation (APBI) is an alternative to whole breast irradiation for early-stage breast cancer.
• MammoSite brachytherapy and 3D-CRT are established APBI techniques.
• SAVI brachytherapy is a newer APBI method requiring dosimetric comparison.

Purpose of the Study:

• To compare the dosimetry of SAVI brachytherapy with MammoSite brachytherapy and 3D-CRT.
• To evaluate coverage and dose to organs at risk for these APBI modalities.

Main Methods:

• Dosimetric comparison of 9 patients eligible for all three APBI techniques (SAVI, MammoSite, 3D-CRT).
• Evaluation of V90, V150, V200, total target volume, and maximum doses to skin, lung, and rib.
• Analysis based on NSABP B-39 guidelines.

Main Results:

• SAVI had the smallest target volume (59.9 cc) compared to MammoSite (71.5 cc) and 3D-CRT (351.6 cc).
• Maximum doses to lung, skin, and rib were lowest with SAVI brachytherapy.
• PTV coverage ranged from 97.6% to 100%, with 3D-CRT covering more breast tissue.

Conclusions:

• SAVI brachytherapy demonstrates superior conformity, resulting in lower maximal doses to adjacent normal tissues like lung, skin, and rib.
• The availability of diverse APBI techniques enhances patient eligibility and allows for tailored treatment selection.
• Further comparison of pros and cons can guide optimal APBI modality choice for individual patients.