Integrating Postmastectomy Radiotherapy and Breast Reconstruction

Abstract

For patients with breast cancer undergoing mastectomy, preserving the breast mound with immediate reconstruction represents a crucial step in preserving quality of life for these patients. In the United States, there has been significant increase in mastectomy rates, accompanied by a similar increase in breast reconstruction rates from 36.9% to 57.2% between 1998 and 2011(1). Another important goal for those patients, is maintaining local tumor control by delivering postmastectomy radiotherapy (PMRT) for certain patients according to national guidelines(2). Other national analyses showed the increased rates of PMRT from 19.1% to 30.3% between 2003 and 2012(3). Despite the increased rates, integrating PMRT in the settings of breast reconstruction is a challenging clinical situation. This challenge arises due to the underlying negative impact of PMRT on breast reconstruction, as it has been established that PMRT increases reconstruction complications(4). The aim of this work is to mitigate the negative PMRT sequelae on breast reconstruction by reducing the complication rates while preserving local tumor control and PMRT benefits. To achieve our goal we study different surgical approaches in the first project and different radiation techniques in the second project. Regarding reconstruction options; the American Society of Plastic Surgeons recommends three different reconstruction types: Autologous, Two Stages Expander/Implant(TE/I) and single stage direct-to-implant (DTI)(5). The Autologous surgery implies reconstructing the breast using a part of another body muscle. Despite the stable cosmetic outcomes for this approach -as it uses native body tissues- the donor site morbidity and longer operation times represent a burden on patients and caregiver. The second approach (TE/I), implies delivering an expander device during mastectomy to allow stretching the skin followed by exchange operation to permanent implant. While this approach avoids donor site morbidity and allows breast augmentation, the need for a second surgery, the challenges during PMRT planning imposed by the expander metal port and worse cosmetic outcomes, represent a major pitfall for this approach. On the other hand, single stage (DTI) an emerging reconstruction option, offers a middle ground between the previous two allowing completion of all operations in one setting with easier PMRT planning. There is still lack of evidence about comparing the three reconstruction types, therefore in the first project we compare the three types with and without PMRT. For radiation techniques, the second project focuses on evaluating the impact of chest wall boost (CWB) on reconstruction complications and local tumor control. CWB is an additional radiation dose delivered to the mastectomy scar using en-face electrons energy. The addition of CWB is thought to improve local control with many conflicting data regarding its benefit. Therefore, our goal in the second project to evaluate its impact on both reconstruction complications and local control. First Project: We compared the 3 different breast reconstruction approaches with and without PMRT. PMRT increased complications across all reconstruction types. However, its impact on single-stage reconstruction was 50% lower than on tissue expander and implant and was close to autologous reconstruction. Single-stage breast reconstruction is a promising strategy, particularly when PMRT is indicated. Second Project: We studied 746 patients who received PMRT and reconstruction; 379 (51%) of them received CWB, and the remaining 367 (49%) did not. On multivariate analysis, CWB was significantly associated with reconstruction complications and failure and was not associated with local tumor control benefits, even in high-risk subgroups.