Naoum George E, Ababneh Hazim S, Niemierko Andrzej, Salama Laura, Ioannidou Myrsini, Smith Barbara L, Colwell Amy, Taghian Alphonse G
Departments of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Int J Radiat Oncol Biol Phys. 2025 Apr 1;121(5):1156-1167. doi: 10.1016/j.ijrobp.2024.11.079. Epub 2024 Nov 30.
For patients with breast cancer receiving mastectomy with direct-to-implant (DTI) immediate breast reconstruction, placing the implant in the prepectoral or subpectoral plane remains debatable, especially in settings of postmastectomy radiation therapy (PMRT).
We reviewed 3039 patients who underwent mastectomy and reconstruction at our institution between 2005 and 2020. Patients receiving DTI with and without PMRT were included. PMRT was delivered either with a photon (3-dimensional-conformal or volumetric arc therapy) or proton therapy, mainly with pencil-beam-scanning. All patients received conventional fractionation (50-50.4 Gy in 25-28 fractions). Primary endpoints were reconstruction complications defined as infection/necrosis requiring debridement; capsular contracture requiring capsulotomy; absolute reconstruction failure entailing permanent removal of the implant without replacement (ie, no salvage reconstruction); and overall reconstruction failure (removal of the implant for any complication with and without salvage reconstruction). Different subgroup analyses were done.
A total of 815 patients met inclusion criteria, with an overall median follow-up of 6.2 years. We found that there is no significant difference between prepectoral versus subpectoral for infection/necrosis (odds ratio [OR], 1.5; P = .3); capsular contracture (OR, 0.97; P = .9); absolute reconstruction failure (OR, 1.9; P = .12); and overall reconstruction failure (OR, 1.2; P = .5). Findings were confirmed using both logistic regression, time-to-event analysis, and multivariable analyses for the entire cohort and subgroups with and without PMRT. There was no significant difference between protons and photons in terms of infection/necrosis (OR, 1.6; P = .4) and absolute reconstruction failure (OR, 1.2; P = .7), but there were significantly higher risks for capsular contracture with protons (OR, 4.4; P < .001) and overall reconstruction failure compared with photons (OR, 2.0; P = .05). We did not find a significant correlation pattern between different dosimetry factors (the average dose, the maximum dose, and volume in cubic centimeter) in either the reconstructed chest wall target or the skin structure, about reconstruction complications, whether for proton or photon patients.
For patients receiving single-stage DTI reconstruction with and without PMRT, prepectoral implant placement had similar rates of complications and reconstruction failure compared with subpectoral reconstruction. Protons compared with photons did not increase the risk of infection/necrosis but significantly increased capsular contracture risks.
对于接受乳房切除术并直接植入式（DTI）即刻乳房重建的乳腺癌患者，将植入物置于胸大肌前或胸大肌下平面仍存在争议，尤其是在乳房切除术后放疗（PMRT）的情况下。
我们回顾了2005年至2020年在本机构接受乳房切除术和重建的3039例患者。纳入接受或未接受PMRT的DTI患者。PMRT采用光子（三维适形或容积弧形放疗）或质子治疗，主要采用笔形束扫描。所有患者均接受常规分割放疗（25 - 28次分割，总剂量50 - 50.4 Gy）。主要终点为重建并发症，定义为需要清创的感染/坏死；需要进行包膜切开术的包膜挛缩；绝对重建失败，即需要永久取出植入物且不进行更换（即无挽救性重建）；以及总体重建失败（因任何并发症取出植入物，无论有无挽救性重建）。进行了不同的亚组分析。
共有815例患者符合纳入标准，总体中位随访时间为6.2年。我们发现，在感染/坏死方面，胸大肌前与胸大肌下之间无显著差异（优势比[OR]，1.5；P = 0.3）；包膜挛缩方面（OR，0.97；P = 0.9）；绝对重建失败方面（OR，1.9；P = 0.12）；以及总体重建失败方面（OR，1.2；P = 0.5）。通过逻辑回归、事件发生时间分析以及对整个队列和有无PMRT的亚组进行多变量分析，证实了这些结果。在感染/坏死（OR，1.6；P = 0.4）和绝对重建失败（OR，1.2；P = 0.7）方面，质子治疗与光子治疗之间无显著差异，但与光子治疗相比，质子治疗导致包膜挛缩的风险显著更高（OR，4.4；P < 0.001），总体重建失败的风险也更高（OR，2.0；P = 0.05）。对于质子治疗或光子治疗的患者，我们未发现重建胸壁靶区或皮肤结构中不同剂量学因素（平均剂量、最大剂量和立方厘米体积）与重建并发症之间存在显著的相关模式。
对于接受单阶段DTI重建且有无PMRT的患者，与胸大肌下重建相比，胸大肌前置入植入物具有相似的并发症发生率和重建失败率。与光子治疗相比，质子治疗不会增加感染/坏死的风险，但会显著增加包膜挛缩的风险。
