Mammographic Changes After Stem Cell Supplemented Fat Transfer to the Breast Compared With Changes After Breast Reduction: A Blinded Study
Devin Coon O'Brien, M.D.1, Margarita Zuley, M.D.2, Jonathan Toy, M.D.2, Yuko Asano, M.D.3, Kotaro Yoshimura, M.D.3, J. Peter Rubin, M.D.2.
1Johns Hopkins Medical Institutions, Baltimore, MD, USA, 2University of Pittsburgh Medical Center, Pittsburgh, PA, USA, 3University of Tokyo, Tokyo, Japan.
Background: With autologous fat displaying many of the properties of an ideal filler, there has been a recent surge of interest in fat grafting for soft tissue defects. However, lipotransfer has continued to present challenges including unpredictability and high rates of adipocyte loss. One technique to reduce these problems is cell assisted lipotransfer (CAL), a novel method of improving fat grafting by enriching the quantity of adipose-derived stem cells present.
Regardless of fat grafting technique, the greatest barrier to acceptance of autologous fat transfer for augmenting breast volume remains safety concerns. The key question of whether lipoaugmentation-induced changes in breast architecture could impede detection of breast cancer has persisted. However, commonly performed surgeries of the breast, most notably reduction mammaplasty, are known to produce radiographic abnormalities without significantly impeding cancer screening.
The goals of this study were therefore to assess whether mammographic changes following breast augmentation with stem cell-supplemented fat grafting are similar to those seen after reduction mammaplasty and whether lipoaugmentation leads to a greater number of suspicious mammographic findings.
Methods: Twenty seven Japanese women who had normal pre-operative mammograms before aesthetic lipoaugmentation underwent repeat mammograms twelve months after surgery. As a control group, one year post-surgical mammograms from twenty three American patients of similar age undergoing breast reduction at the University of Pittsburgh Medical Center were compared.
Eight attending radiologists reviewed each post-surgical mammogram in a blinded fashion. Analysis of the differences in outcomes accounting for both the repeated readings and individual radiologist tendencies was performed using a generalized estimating equation linked to a logistic function.
Results: The average volume of fat injected per patient was 526.5cc. Fifty mammograms (27 lipotransfer, 23 breast reduction) were reviewed by eight radiologists (400 assessments). Differences between individual radiologists were relevant (p<0.10) for each type of finding. When accounting for this and the repeated readings, the differences in abnormality rates were non-significant for oil cysts (p=0.15), benign calcifications (p=0.1), and calcifications warranting biopsy (p=0.1). Scarring (p<0.001) and masses requiring biopsy (p<0.001) were significantly more common in the breast reduction cohort.
BIRADS scores were significantly worse after breast reduction (p<0.001). Rates of immediate biopsy recommendation versus followup study recommendation were non-significantly greater in the breast reduction group (p=0.12). Differences in the recommended followup time were seen, favoring the lipoaugmentation cohort (p<0.01).
Conclusions: Structural fat grafting represents an area of plastic surgery receiving rapidly increasing interest. Technological advances including technique refinements and adipose-derived stem cell enhanced grafts have the potential to broaden the role of fat transfer in clinical plastic surgery. However, lipoaugmentation of the breast has been controversial due to concerns regarding interference with mammography and cancer surveillance. We have demonstrated that when compared to a widely accepted procedure, reduction mammaplasty, lipoaugmentation with the addition of stem cells produces lower rates of radiographic abnormalities and a more favorable BIRADS score.
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