A dosimetric comparison of the Contura multilumen balloon breast brachytherapy catheter vs. the single-lumen MammoSite balloon device in patients treated with accelerated partial breast irradiation at a single institution.

PURPOSE

A comparison of dosimetric findings in 33 patients treated with the Contura multilumen balloon (SenoRx Inc., Irvine, CA) (C-MLB) breast brachytherapy catheter vs. 33 patients treated with the MammoSite (Hologic Inc., Bedford, MA) (MS) at a single institution to deliver accelerated partial breast irradiation (APBI) was performed.

METHODS AND MATERIALS

CT-based 3-dimensional planning with dose optimization was completed. APBI treatment of 34Gy in 3.4Gy fractions was delivered. Endpoints analyzed included: (1) The percentage of the prescribed dose (PD) covering the planning target volume (PTV), (2) the maximum skin dose as a percentage of the PD, (3) the maximum rib dose as a percentage of the PD, and (4) the V150 and V200.

RESULTS

The C-MLB was placed more frequently in patients with closer skin spacing (<7mm) and rib spacing (<7mm) than in MS patients (45.5% vs. 12.1%, p=0.0057 and 57.6 vs. 33.3, p=0.0131, respectively). Despite closer skin spacing, the overall median skin dose was significantly lower in C-MLB patients (112% of the PD vs. 134%, p=0.0282). No statistically significant differences in the V150 or V200 were observed. In patients with very limited rib spacing (<4mm), the C-MLB delivered significantly lower rib doses than the MS (144% of the PD vs. 191%, p=0.0107). In all clinical scenarios, coverage of the PTV with the C-MLB was either equal to or significantly better than with the MS (p=0.0024).

CONCLUSION

The C-MLB catheter produced clinically significant improvements in dosimetric endpoints (e.g., reduced skin and rib doses and improved PTV coverage) in most clinical scenarios.