Three year analysis of patient demographics, treatment efficacy, cosmesis, and toxicity by the American Society of Breast Surgeons MammoSite® registry in patients (age &lt;50 or ≥ 50) treated with accelerated partial breast irradiation (APBI).
Authors: Thanasoulis LC , Vicini F , Beitsch PD , Lyden M 
Published: December 2010

Abstract #5126

Background: We present 3 year data on patient demographics, treatment efficacy, cosmesis, and early toxicity for patients enrolled on the American Society of Breast Surgeons MammoSite (Hologic Bedford, MA) Registry based upon patient age (&lt;50 versus ≥50).&#x2028; Material and Methods: From 5/02 to 7/04, 1449 breasts (1440 patients) with Stage 0-II breast cancer undergoing breast-conserving therapy were treated with the MammoSite device to deliver APBI (34 GY in 3.4 Gy fractions). Of these 1449 breasts, 1255 (86.6%) breasts had invasive breast cancer (IBC; median size 10mm) and 194 (13.3%) breasts had ductal carcinoma in situ (DCIS; median size 8mm). Of the 1255 IBC breasts/1249 patients, 109 (8.68%) breasts/patients were &lt;50 years of age (YOA) and 1140/1146 (91.3%) patients/breasts were ≥ 50. Of the 194 DCIS breasts/patients, 21 (10.8%) patients were &lt;50 YOA and 173 (89.2%) patients were ≥ 50. Prognostic factors, technique, cosmesis, recurrence rates, and toxicity were assessed for all patients. Median follow-up was 38 months.&#x2028; Results: Of the IBC cases, 3 (2.8%) breasts (age&lt;50) and 20 (1.7%) breasts (age≥50) developed an ipsilateral breast tumor recurrence (IBTR) for a 3 year actuarial rate (YAR) of 2.27% and 1.76%, respectively (p=0.4587). Of the DCIS patients, 1 (4.8%) breast (age&lt;50) and 1 (0.6%) breast (age≥50) developed an IBTR for a 3 YAR of 6.25% and 1.4%, respectively (p=0.2575). Of the IBC cases, patients &lt;50 YOA compared to age ≥ 50 more frequently had positive nodes (6.4% vs 2.7%, P = .04), higher grade (≥ II) (72.5% vs 58.9%, P=.0056), and were treated with chemotherapy (31.2% vs 11.5%, P&lt;.0001). No significant difference was found in margin status, tumor location and size, extensive intraductal component, and use of tamoxifen based on age. Of the DCIS cases, patients &lt;50 YOA compared to patients ≥ 50 more frequently had an open cavity MammoSite placement (81% vs 52%, P = .0184). No significance was found in margin and node status, tumor location or size, histology, and use of tamoxifen due to age. Patients &lt;50 compared to ≥ 50 with IBC or DCIS had excellent/good cosmetic 3 year outcome (YO) (90.3%) and (93.3%), respectively (p=0.2902). Patients &lt;50 compared to ≥ 50 with IBC or DCIS more frequently experienced a fair/poor cosmetic 2 YO (13.5% vs 5.6%, P=0.0197) and fat necrosis (4.6% vs 1.8%, P=.0456). This fair/poor cosmetic 2 YO finding for patients &lt;50 vs. &gt; 50 was not significant at 3 YO (9.7% vs 6.4%, p=0.2902). No difference due to age was found for seroma formation, breast infection, telengectasia, retraction, skin spacing, placement method, bra size and balloon volume.&#x2028; Discussion: Treatment efficacy, cosmesis, early toxicity and IBTR 3 years after treatment with APBI using the MammoSite device were similar for IBC and DCIS patients for age&lt;50 or ≥ 50 years at diagnosis.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5126.