Abstract P5-14-04: Patterns of Locoregional Failure in Women with Invasive Breast Cancer Treated with Mastectomy and Tissue Expander/Implant Reconstruction

Abstract

BACKGROUND: Breast reconstruction with a tissue expander/implant (TE/I) following mastectomy for invasive breast cancer poses unique challenges in detecting local recurrence and in the technical delivery of post-mastectomy radiotherapy (PMRT). For women identified as having high risk disease, PMRT lowers the risk of locoregional failure (LRF) and enhances long-term survival. The aim of this study was to evaluate the patterns of LRF in women who underwent mastectomy and implant reconstruction, with or without adjuvant PMRT. METHODS: We performed a retrospective review of all patients undergoing mastectomy with TE/I reconstruction for non-metastatic invasive breast cancer from 2001-2006 at the Cleveland Clinic, after approval from the institutional review board. The presence and location of locoregional recurrence was noted. Kaplan-Meier curves were generated to estimate locoregional recurrence free survival (LRFS) and overall survival (OS) rates. RESULTS: The study population consisted of 326 patients: 121 (37%) with pathologic stage I disease, 128 (39%) with stage II, 46 (14%) with stage III, and 31 (10%) who underwent neoadjuvant systemic therapy prior to mastectomy. The median number of lymph nodes dissected was 10 and the median follow-up was 5.5 years. The OS for all patients at 5 years was 92.4%. By stage, 5-year OS was 95.9% for stage I, 94.4% for stage II,87.2% for stage III, and 79.6% for those undergoing pre-operative systemic therapy. The LRFS at 5 years for all patients was 91.3%. The 5-year LRFS was 95.4% for stage I, 93.6% for stage II, 79.4% for stage III, and 87.4% for those who underwent pre-operative systemic therapy. 8% of all patients had a LRF. By lymph node status, node-negative patients (N0) had a LRF rate of 4.8% (9/189), those with 1-3 nodes positive (N1) had a LRF rate of 5.0% (4/80), those with 4-9 nodes positive (N2) had a LRF rate of 17.5% (7/40), and those with 10 or more nodes positive (N3) had a LRF rate of 50% (6/12). The most common sites of LRF were cutaneous chest wall (8/26) and axilla (8/26), followed by the supraclavicular/cervical nodes (5/26) and chest wall with muscle involvement (3/26). The remaining 2/26 failed at a combination of the above sites. 21.2% of the total population (69/326) underwent PMRT to the chest wall and regional nodes. By nodal status, including those who received neoadjuvant systemic therapy, 7.4% of women with zero nodes positive underwent radiation, followed by 18.8% with 1-3 nodes positive, and 76.9% with 4 or more nodes positive. CONCLUSIONS: The crude rate of LRF in this large institutional series is similar to what has been previously reported in the literature. In our population, LRF in the superficial chest wall occurred at the same rate as the axillary nodes, which was followed in frequency by the supraclavicular/cervical nodes. Nearly 1/4 of women with 4 or more positive axillary nodes underwent no adjuvant radiation therapy following mastectomy, despite being a population of women known to derive benefit from PMRT. Further investigation is required to determine whether the presence of a TE/I reconstruction alters decision-making for adjuvant local therapy and/or impacts the technical delivery of PMRT. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-14-04.