Imaging and Receptor Status as Predictors of Pathologic Complete Response to Neoadjuvant Chemotherapy in Breast Cancer

Results: Median follow-up was 16 months. The minimum balloon-to-skin distance was\7 mm in 16% (7/45) of Contura patients and 12% (17/137) of MammoSite patients (p=0.78). The maximum skin dose was 100% of the prescribed dose with a Contura catheter vs. 145% of the prescribed dose with a MammoSite catheter. Air/fluid next to the Contura balloon was at least partially removed in 71% (32/45) of patients. The volume of air/fluid next to the Contura balloon was 5.0% ± 0.7% (mean ± standard error) of the planning target volume for plan evaluation (PTV_EVAL) before suctioning vs. 1.3% ± 0.2% after suctioning (p\ 0.001). Eighty-nine percent (40/45) of Contura plans satisfied both treatment planning goals vs. only 36% (16/45) of hypothetical MammoSite plans (p \ 0.0001). A Contura catheter did not require explantation in 16% (7/45) of patients where balloon-toskin spacing was only 3-6 mm and in 11% (5/45) of patients where there was an air/fluid pocket next to the balloon .10% of PTV_EVAL prior to suctioning. A MammoSite catheter was explanted in 10% (15/152) of cases where the minimum balloon-to-skin distance was \7 mm and in 13% (20/157) of cases where there was an air/fluid pocket next to the balloon .10% of PTV_EVAL. The incidence of acute toxicity with a Contura catheter was similar to that with a MammoSite catheter. Conclusions: A Contura catheter does not require explantation in cases where balloon-to-skin spacing is only 3-6 mm or an air/ fluid pocket next to the balloon is .10% of PTV_EVAL prior to suctioning, thereby increasing the applicability of accelerated partial breast irradiation. Phase III clinical trials will help to determine whether accelerated partial breast irradiation offers advantages over standard whole breast irradiation.