Mammographic Changes After Stem Cell Supplemented Fat Transfer to the Breast Compared with Changes After Breast Reduction: A Blinded Study

Background:  With autologous fat displaying many properties of an ideal filler, there has been a recent surge of interest in fat grafting for soft tissue defects. One novel method of improving graft survival is cell-assisted lipotransfer (CAL), involving enrichment of the graft with existing adipose-derived stem cells.

However, the key question of whether lipoaugmentation-induced changes in breast architecture impede detection of breast cancer has persisted. Common breast surgeries, including reduction mammaplasty, are known to produce radiographic abnormalities without impeding cancer screening. The goals of this study were therefore to assess whether mammographic changes following fat grafting to the breast 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 with 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 were compared.

Eight attending radiologists reviewed each mammogram in a blinded fashion.  Analysis of differences in outcomes accounting for both 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 were reviewed by eight radiologists. Differences between radiologists were relevant (p<0.10) for each type of finding. When accounting for this and 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.

Rates of immediate biopsy versus followup study recommendation were non-significantly greater in the breast reduction group (p=0.12). Differences in suggested followup time favored the lipoaugmentation cohort (p<0.01). BIRADS scores were worse after breast reduction (p<0.001).

Conclusions: Structural fat grafting represents an area of plastic surgery receiving increasing interest. Technological advances have the potential to broaden the role of fat transfer in clinical plastic surgery. However, breast lipoaugmentation 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 stem cell enrichment produces lower rates of radiographic abnormalities and a more favorable BIRADS score.