Brachytherapy in accelerated partial breast irradiation (APBI) - review of treatment methods

Abstract

Breast conserving surgery (BCS) with following radiotherapy (EBRT) of the conserved breast became widely accepted in the last decades as the treatment of early invasive breast cancer. In an early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent cancer from local recurrence is the breast tissue that surrounds the area where the initial cancer was removed. Accelerated partial breast irradiation (APBI) is an approach that treats only the lumpectomy bed with 1-2 cm margin, rather than the whole breast and as a result allows accelerated delivery of the radiation dose in four to five days. Published results of APBI are very promising. It is evident that APBI will play a role in the management of a selected group of early breast cancer. We discuss current status, indications, technical aspects and recently published results of APBI using different brachytherapy techniques.

Keywords: APBI; balloon; brachytherapy; breast cancer; interstitial.

Fig. 1

Schematic location of the satellite foci of cancer in the immediate vicinity of the primary tumor

Fig. 2

Interstitial brachytherapy for breast cancer – implantation of 7 flexible applicators attached to the skin with buttons, the tumor bed localized by ultrasound

Fig. 3

Example of 3D treatment plan for breast cancer, indicating target, applicators, and critical organs (plan prepared by Oncentra Prostate^®)

Fig. 4

The distribution of dose (isodoses) obtained after the preparation of the treatment plan, target CT cross-sections performed every 2-3 mm

Fig. 5

Examples of applicators used in interstitial brachytherapy, A) from Varian Medical Systems (Breast Catheter Kits), B) from Nucletron Applicator Guide (Breast Template Set “Rabbit”)

Fig. 6

A) MammoSite device used in balloon brachytherapy (Hologic^®, Marlborough). B) MammoSite balloon applicator in CT cross section with the indication of lung

Fig. 7

A) Contura balloon applicator (SenoRx^®) [30]. B) Contura balloon applicator on CT section with the distribution of isodoses, 5 channels for iridium visible

Fig. 8

A) Applicator SAVI (Strut Adjusted Volume Implant) with expanded channels (Cianna Medical^®) [30]. B) SAVI applicator X-ray images showing surgical clips (arrows) [35]. C) SAVI applicator, a balloon with a visible isodoses [35]

Fig. 9

Example of 3D treatment plan for breast cancer, indicating target, applicators, and critical organs (plan prepared by Oncentra Prostate^®) A) Axxent Electronic Brachytherapy System, the control unit (Xoft^®) [30]. B) Axxent Electronic Brachytherapy System, X-ray source HDR (Xoft^®) [30]. C) Axxent Electronic Brachytherapy System, a balloon applicator (Xoft^®) [30]