S. Koduri1, J. M. Karp2, J. Xiao3, C. Boyd4, N. Karp5, M. Choi4, F. Schnabel6, N. K. Gerber3, and J. Purswani7; 1Department of Radiation Oncology, NYU Langone Health, New York City, NY, 2NYU Langone Medical Center, New York City, NY, 3New York University Grossman School of Medicine, Department of Radiation Oncology, New York, NY, 4NYU Langone Health, New York City, NY, 5Department of Surgery, NYU Langone Health and Perlmutter Cancer Center, New York, NY, 6NYU Grossman School of Medicine, New York, NY, 7Albert Einstein College of Medicine, Montefiore Medical Center, Bronx, NY
Purpose/Objective(s): In breast cancer patients (pts) who undergo mastectomy with reconstruction and radiation (RT), there is limited data on how reconstruction outcomes after RT vary based on the type of surgery performed. We report the outcomes in a cohort of women treated with nipple or skin sparing mastectomy (NSM or SSM) and RT to the reconstructed breast. Materials/
Methods: 125 pts planned for NSM/SSM with single or 2 stage implant reconstruction (IR) or autologous reconstruction (AR) and RT were retrospectively evaluated. Planned vs. actual reconstruction technique was collected. Reconstruction complications were defined as necrosis requiring debridement, dehiscence, and capsular contracture. Reconstruction failure (RF) was defined as complete loss of an autologous flap, implant explantation or unplanned tissue expander (TE) removal. Overall survival (OS), disease-free survival (DFS), and locoregional recurrence free survival (LRFS) were estimated using the Kaplan-Meier method. Results: 101 (81%) were initially planned for IR (8 [8%] single-stage and 93 [92%] 2-stage TE to implant) and 24 (19%) as AR (4 [17%] single-stage and 20 [83%] 2-stage). Patients in the planned IR vs. AR group had similar baseline characteristics of age (mean 46 years vs. 48 years), cT3/4 stage (32% vs 29%), cN3/4 (15% vs 13%), close/positive margins (25% vs 21%), and neoadjuvant chemotherapy (49% vs 42%). 87 (70%) received RT to the TE (RT-TE), of which 77% were in the planned IR group and 23% in the planned AR group. 35 (28%) underwent RT to the final implant (RT-I) and 3 (2%) to the autologous flap (RT-A). Median RT dose was 50 Gy (range 40.5 – 50.4); 98% received 3D conformal RT, 3% chest wall boost, 16% boost to nodal areas and 15% bolus. Rate of necrosis was 8% with RT-E, 0% RT-I and 0% RT-A. Rate of dehiscence was 5% with RT-E, 3% with RT-I and 0% with RT-A. Rate of capsular contracture was 36% with RT-E, 46% with RT-I and 0% with RT-A. RF occurred in 17% with RT-E, 11% with RT-I and 0% with RT-A. Median time to RF after RT was 15 months (95% CI 9 - 51). In the planned IR group, 17 (17%) ultimately did not receive IR, of which 59% had capsular contracture, 6% dehiscence and 47% RF of the TE. 12 (71%) underwent final AR instead and 5 (30%) had no final reconstruction. In the planned AR group, 5 (21%) did not receive AR, of which 20% had capsular contracture, 0% dehiscence and 0% RF of the TE. 2 (40%) underwent final IR instead and 3 (60%) had no final reconstruction. Median follow-up was 60 months (IQR: 50 – 73). 5-year LRFS was 97%, DFS was 90% and OS was 93%. There was 4 LRs (2 regional node [RN], 1 chest wall and 1 cutaneous + RN) all associated with distant failure at time of recurrence. Conclusion: Most pts underwent planned 2-stage IR with a majority receiving RT to the TE. 17% of the planned IR group did not receive intended reconstruction, many of whom had capsular contracture after RT to the TE and underwent AR instead. Rates of RF and complications were highest in the group who received RT to the TE followed by the implant group. Lowest risk of complications was in the AR group.
