Accelerated Partial Breast Irradiation (APBI): A review of available techniques

Abstract

Breast conservation therapy (BCT) is the procedure of choice for the management of the early stage breast cancer. However, its utilization has not been maximized because of logistics issues associated with the protracted treatment involved with the radiation treatment. Accelerated Partial Breast Irradiation (APBI) is an approach that treats only the lumpectomy bed plus a 1-2 cm margin, rather than the whole breast. Hence because of the small volume of irradiation a higher dose can be delivered in a shorter period of time. There has been growing interest for APBI and various approaches have been developed under phase I-III clinical studies; these include multicatheter interstitial brachytherapy, balloon catheter brachytherapy, conformal external beam radiation therapy and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include Mammosite, Axxent electronic brachytherapy and Contura, Hybrid brachytherapy devices include SAVI and ClearPath. This paper reviews the different techniques, identifying the weaknesses and strength of each approach and proposes a direction for future research and development. It is evident that APBI will play a role in the management of a selected group of early breast cancer. However, the relative role of the different techniques is yet to be clearly identified.

Figure 1

Diagrammatic illustration of multi-catheter interstitial brachytherapy.

Figure 2

The MammoSite Balloon applicator (courtesy of Hologic, Marlborough).

Figure 3

The MammoSite Multilumen System (courtesy of Hologic, Marlborough).

Figure 4

Axxent electronic brachytherapy, controller front view (courtesy of Xoft).

Figure 5

Axxent electronic brachytherapy, HDR X-ray source (courtesy of Xoft).

Figure 6

Axxent electronic brachytherapy, balloon applicator (courtesy of Xoft).

Figure 7

The Contura balloon applicator (courtesy of SenoRx).

Figure 8

Different sizes of SAVI with peripheral struts expanded (courtesy of Cianna Medical).

Figure 9

ClearPath device (a) the base detached (b) a cap placed over the HDR channels (courtesy of North America Scientific).

Figure 10

3D-CRT typical 4-field arrangement for right sided lesions and 5 field arrangement for left sided lesions (reprinted with permission from Baglan et al.[93].

Figure 11

The mobile X-ray intraoperative radiation therapy device: The Intrabeam device intraoperative photon device.

Figure 12

Various spherical applicators with diameters ranging from 1.5 to 5 cm used in the intrabeam device (reprinted with permission Holmes et al: [117].

Figure 13

The mobile electron intraoperative radiation therapy devices: (a) Novac7 (b) Mobetron intra-operative electron device (reprinted with permission Beddar el al. [124]).