Abstract 42: The Influence Of Fat Grafting On Breast Imaging After Post-mastectomy Reconstruction: A Matched Cohort Analysis

Abstract

Purpose: Fat grafting is a common adjunct procedure in breast reconstruction. While shown to have a safe oncologic profile, it may result in the development of palpable masses on physical exam, prompting further investigation with imaging and biopsy. The aim of this study was to assess the influence of fat grafting on the incidences of palpable masses, imaging, and biopsies after post-mastectomy breast reconstruction. Methods: Patients who underwent autologous or implant-based reconstruction following mastectomy from 2010-2018 were identified. Those receiving fat grafting as part of their reconstructive course were propensity matched in a 1:1 ratio to those that did not undergo a fat grafting procedure with BMI, reconstruction timing, and reconstruction type as covariates in a multivariable logistic regression model. Results: A total of 186 patients were identified, yielding 93 propensity-matched pairs. Patients that underwent fat grafting had higher incidences of palpable masses (38.0% vs. 18.3%; p=0.003) and post-reconstruction imaging (47.3% vs. 29.0%; p=0.01). However, there was no significant difference in the number of biopsies performed between patients who did and did not receive fat grafting (11.8% vs. 7.5%; p=0.32). When looking at imaging characteristics amongst the fat grafted cohort, imaging was predominately interpreted as normal (BIRADS 1, 27.9%) or benign (BIRADS 2, 48.8%), with fat necrosis being the most common finding (n=20, 45.5%). No demographic, oncologic, reconstructive, or fat grafting-specific variables were independently predictive of receiving post-reconstruction imaging in multivariate analysis when controlling for follow-up time. On Kaplan-Meier analysis, fat grafting was not associated with decreased 5-year overall survival or locoregional recurrence-free survival. Conclusions: Fat grafting to the reconstructed breast is associated with increased incidences of palpable masses and subsequent post-reconstruction imaging. However, fat grafted patients do not undergo more biopsies, owing to the successful identification of fat-related changes on imaging. Thus, patients should be counseled in the preoperative period that they may be more likely to detect a palpable mass following fat grafting, and may be subject to more diagnostic imaging. Patients should be reassured, however, that fat grafting has a safe oncologic profile and does not affect overall or locoregional recurrence-free survival.