Brachytherapy in breast cancer: an effective alternative

Abstract

Breast conserving surgery (BCS) with following external beam radiation therapy (EBRT) of the conserved breast has become widely accepted in the last decades for the treatment of early invasive breast cancer. The standard technique of EBRT after BCS is to treat the whole breast up to a total dose of 42.5 to 50 Gy. An additional dose is given to treated volume as a boost to a portion of the breast. In the early stage of breast cancer, research has shown that the area requiring radiation treatment to prevent the 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 plus a 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. There has been a 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 (3D-EBRT) and intra-operative radiation therapy (IORT). Balloon-based brachytherapy approaches include MammoSite, Axxent electronic brachytherapy, Contura, hybrid brachytherapy devices. Another indication for breast brachytherapy is reirradiation of local recurrence after mastectomy. Published results of brachytherapy are very promising. We discuss the current status, indications, and technical aspects of breast cancer brachytherapy.

Keywords: APBI; boost; brachytherapy; breast cancer; recurrence.

Fig. 1

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

Fig. 2

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

Fig. 3

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

Fig. 4

A) Contura balloon applicator (SenoRx^®) [36]. B) Contura balloon applicator on CT section with the distribution of isodoses, 5 channels for iridium visible

Fig. 5

A) Applicator SAVI (strut adjusted volume implant) with expanded channels (Cianna Medical^®) [36]. B) SAVI applicator, a balloon with visible isodoses [35]