Intracavitary Balloon Brachytherapy in Breast Cancer (Mammosite)

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Introduction:
Intracavitary balloon brachytherapy (IBB) has been postulated as an alternative to external radiotherapy in the treatment of early-stage breast cancer, and consists of the administration of radiotherapy using accelerated fractionation with concomitant boost via a catheter connected to a balloon. This technique reduces the volume of irradiation and allows for greater treatment fractions in a shorter application time.

Objetives: This study sought to: assess the effectiveness of IBB as adjuvant treatment to conservative surgery in early-stage breast cancer in terms of recurrence, survival, cosmetic results and patient satisfaction; and ascertain the safety of this procedure in terms of the toxicity of radiotherapy.

Methods: A search was made of the scientific literature, from January 2006 to January 2010, in the following databases: Medline; Embase; Health Technology Assessment (HTA); Database of Abstracts of Reviews of Effectiveness (DARE); NHS Economic Evaluation Database (NHSEED); Web of Science; Cochrane Library Plus; Clinical Trials Registry; International Clinical Trials Registry Platform; and Current Controlled Trials. From among the papers yielded by the bibliographic search, only those were selected that met the selection criteria; data were then extracted and the evidence summarized

Results and Discussion: A total of 61 studies were selected for assessment of the complete text. Of these, 28 -all of which were observational in nature- met the inclusion criteria. All the studies applied strict patient selection criteria. The observed rate of recurrence was low, with 8.1% being the highest value and elevated survival rates of around 95%. In most studies, the cosmetic results obtained were good/excellent in >90% of patients. The technique appeared to be safe, and its most frequent side-effects were development of: seroma, with values ranging from 10% to 76.3%; infection, with values ranging from 1% to 12%; and breast fat necrosis, with values of under 10% in all cases. Key factors that determined worse results were: open versus percutaneous technique; balloon-toskin spacing <7mm; and, in the case of recurrence, an extensive intraductal component.

Conclusions:To date, IBB has yielded acceptable results in terms of efficacy and safety, yet the absence of long-term studies means that it cannot be claimed to be as effective as other forms of treatment in terms of survival. For the purposes of this technique, suitable selection of eligible patients is essential, i.e., those with a low risk of tumor spread outside the original tumor-bed. When it comes to implementing IBB, the type of technique used (open or closed) and its resulting variables, such as balloon-to-skin spacing, the fit of the balloon to the lumpectomy cavity and balloon symmetry with respect to the catheter, are considered critical. Before any final conclusions can be drawn, prospective studies with a longer follow-up time are called for, as are randomized clinical trials that will enable indepth knowledge to be gained of the technique's effectiveness and safety.