Utilizing large volume fat grafting in breast reconstruction after nipple sparing mastectomies

Exosomes from Adipose-Tissue-Derived Stem Cells Induce Proapoptotic Gene Expression in Breast Tumor Cell Line

Lipofilling is an option for breast reconstruction after tumor resection to avoid the complications of an implant-based reconstruction. Although some concerns exist regarding the oncological safety of tissue rich in mesenchymal stem cells with their proangiogenic and proliferation-supportive properties, there are also reports that adipose-tissue-derived stem cells can exhibit antitumoral properties. We isolated primary adipose-tissue-derived stem cells. Both conditioned medium and exosomes were harvested from the cell culture and used to treat the breast cancer cell line MCF-7. Cell viability, cytotoxicity, and gene expression of MCF-7 cells in response to the indirect co-culture were evaluated. MCF-7 cells incubated with exosomes from adipose-tissue-derived stem cells show reduced cell viability in comparison to MCF-7 cells incubated with adipose-tissue-derived stem-cell-conditioned medium. Expression of proapoptotic genes was upregulated, and expression of antiapoptotic genes was downregulated. The debate about the oncological safety of autologous fat grafting after tumor resection continues. Here, we show that exosomes from adipose-tissue-derived stem cells exhibit some antitumoral properties on breast cancer cell line MCF-7.

Postoperative Antibiotics Confer No Protective Association After Fat Grafting for Breast Reconstruction

INTRODUCTION

Autologous fat grafting after breast reconstruction is a commonly used technique to address asymmetry and irregularities in breast contour. While many studies have attempted to optimize patient outcomes after fat grafting, a key postoperative protocol that lacks consensus is the optimal use of perioperative and postoperative antibiotics. Reports suggest that complication rates for fat grafting are low relative to rates after reconstruction and have been shown to not be correlated to antibiotic protocol. Studies have additionally demonstrated that the use of prolonged prophylactic antibiotics do not lower the complication rates, stressing the need for a more conservative, standardized antibiotic protocol. This study aims to identify the optimal use of perioperative and postoperative antibiotics that optimizes patient outcomes.

METHODS

Patients in the Optum Clinformatics Data Mart who underwent all billable forms of breast reconstruction followed by fat grafting were identified via Current Procedural Terminology codes. Patients meeting inclusion criteria had an index reconstructive procedure at least 90 days before fat grafting. Data concerning these patient's demographics, comorbidities, breast reconstructions, perioperative and postoperative antibiotics, and outcomes were collected via querying relevant reports of Current Procedural Terminology; International Classification of Diseases, Ninth Revision; International Classification of Diseases, Tenth Revision; National Drug Code Directory, and Healthcare Common Procedure Coding System codes. Antibiotics were classified by type and temporal delivery: perioperatively or postoperatively. If a patient received postoperative antibiotics, the duration of antibiotic exposure was recorded. Outcomes analysis was limited to the 90-day postoperative period. Multivariable logistic regression was performed to ascertain the effects of age, coexisting conditions, reconstruction type (autologous or implant-based), perioperative antibiotic class, postoperative antibiotic class, and postoperative antibiotic duration on the likelihood of any common postoperative complication occurring. All statistical assumptions made by logistic regression were met successfully. Odds ratios and corresponding 95% confidence intervals were calculated.

RESULTS

From more than 86 million longitudinal patient records between March 2004 and June 2019, our study population included 7456 unique records of reconstruction-fat grafting pairs, with 4661 of those pairs receiving some form of prophylactic antibiotics. Age, prior radiation, and perioperative antibiotic administration were consistent independent predictors of increased all-cause complication likelihood. However, administration of perioperative antibiotics approached a statistically significant protective association against infection likelihood. No postoperative antibiotics of any duration or class conferred a protective association against infections or all-cause complications.

CONCLUSIONS

This study provides national, claims-level support for antibiotic stewardship during and after fat grafting procedures. Postoperative antibiotics did not confer a protective benefit association against infection or all-cause complication likelihood, while administering perioperative antibiotics conferred a statistically significant increase in the likelihood that a patient experienced postoperative complication. However, perioperative antibiotics approach a significant protective association against postoperative infection likelihood, in line with current guidelines for infection prevention. These findings may encourage the adoption of more conservative postoperative prescription practices for clinicians who perform breast reconstruction, followed by fat grafting, reducing the nonindicated use of antibiotics.

Review of Autologous Fat Grafting in Postmastectomy Reconstruction Patients: Nonroutine Diagnostics and Oncologic Safety

Autologous fat grafting (FG) is increasingly used as an adjunctive reconstruction technique to augment volume, achieve symmetry, and improve contour deformities. This study aims to characterize the oncologic and surgical safety of FG in women undergoing autologous breast reconstruction (ABR) or implant-based reconstruction (IBR).

METHODS

A retrospective chart review was performed for all patients undergoing FG at a multi-site single health system between 2015 to 2018. A total of 228 eligible breasts from 155 patients were identified using Current Procedural Terminology codes. Patients were divided by reconstructive technique. Bivariate analyses compared baseline characteristics and post-FG outcomes.

RESULTS

Mean age for patients undergoing ABR (129 breasts) was 52.8 years compared to 48.6 years for those undergoing IBR (99 breasts; P = 0.002). A heavier volume of fat was grafted per ABR breast (143.8mL) than per IBR breast (102.2mL; P = 0.002). Forty-seven (20.6%) breasts required FG revision, more frequently in ABR breasts (31.0%) than IBR breasts (7.1%; P < 0.001). Following FG, 17.5% of patients experienced a palpable mass, and 18.9% of breasts underwent nonroutine diagnostics or procedures, with no difference between ABR and IBR groups. Most biopsies noted benign findings such as fat necrosis (2.2%) or a benign mass (0.9%), with recurrence only noted in two patients (0.9%). Mean follow-up was 20.4 months.

CONCLUSION

FG is a safe, surgically simple procedure more commonly performed in ABR breasts. FG use in ABR and IBR breasts is oncologically safe, with no impairment in breast surveillance and low rates of locoregional recurrence, but possibly increased incidence of nonroutine imaging and biopsies.

Oncological Safety of Autologous Fat Grafting in Breast Reconstruction: A Meta-analysis Based on Matched Cohort Studies

BACKGROUND

Autologous fat grafting has become a commonly used procedure for breast reconstruction after breast cancer surgical treatment. Nevertheless, oncological considerations remain concerning autologous fat grafting after breast cancer surgery.

OBJECTIVE

This meta-analysis aimed to summarize the current matched cohort studies and provide high-quality evidence-based conclusions on the oncological safety of fat grafting in breast reconstruction.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines were followed. A literature search was performed on August 1, 2021, using PubMed. All relevant matched cohort studies of patients undergoing autologous fat grafting after breast cancer surgery were included. After independently screening the studies and extracting the data, pooled estimates for local and regional recurrence as well as distant metastases were conducted using Review Manager software (RevMan, version 5.3). Outcomes were expressed as odds ratios and 95% confidence intervals.

RESULTS

Seventeen studies involving 7494 patients were included. The observed outcomes indicated that no significant differences existed in the risks of local and regional recurrence or distant metastases between autologous fat grafting and control groups. Also, there was no significant heterogeneity among the studies.

CONCLUSION

This study provided evidence-based conclusions that support the use of autologous fat grafting in breast reconstruction.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Breast Reconstruction- Developing a Volumetric Outcome Algorithm

Postoperative loss of breast volume represents a significant parameter for outcome evaluation of breast reconstruction. Breast volume broadly varies- depending of reconstruction method as well as surgical differences. A structural pattern of breast volume loss provides an essential parameter for preoperative design, helps to reduce postoperative breast asymmetry rate and thereby the need for reoperation. Therefore we hereby compare volume change of the three main reconstruction techniques: autologous flap-based, prosthesis-based and autologous fat transplantation breast reconstruction. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Palpable Nodules After Autologous Fat Grafting in Breast Cancer Patients: Incidence and Impact on Follow-up

INTRODUCTION

Autologous fat grafting (AFG) is a promising breast reconstruction technique, following surgery. However, fat necrosis after AFG can cause palpable nodules, inducing anxiety and prompting additional investigations. We aimed to determine the occurrence rate and to identify the risk factors of palpable nodules in breast cancer patients prompting complementary explorations.

MATERIALS AND METHODS

We retrospectively reviewed the computerized files of consecutive breast cancer patients who underwent AFG after mastectomy or breast conservative treatment (BCT) at our center from January 2013 to December 2016. We collected data regarding palpable nodule incidences and suspicious breast imaging findings that led to additional explorations.

RESULTS

Of the 252 patients reviewed, 222 (88%) underwent AFG for breast reconstruction, while 30 (12%) underwent AFG for correction of defects after BCT. The follow-up period ranged from 0 to 74 months (median: 27 months), and 201 patients had follow-ups beyond 1 year. Of the 252 patients, 66 (26.2%) underwent at least one control imaging and 24 (10%) underwent a biopsy, including 6 (2.4%) locoregional recurrence. Sixty patients (24%) were diagnosed with nodules during follow-ups. Among them, 52 (87%) patients had additional imaging, and 17 patients (28%) had a biopsy, including 82% benign histology. Patients with BCT had significantly more palpable nodules at 1 year than patients who underwent total mastectomy (odds ratio = 2.50, 95% confidence interval: 1.04. 6.03, p = 0.04).

CONCLUSION

This study underlines the importance of preoperative patient information. This intervention and its follow-up should be reserved for experienced teams to limit unnecessary additional explorations.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evaluation of the ex vivo Effects of Tamoxifen on Adipose-Derived Stem Cells: A Pilot Study

Autologous fat grafting (AFG) is a safe and minimally invasive procedure to correct soft tissue defects. The benefit of AFG is attributed to adipose-derived stem cells (ASCs) in fat tissue graft. This technique is useful also in patients undergoing reconstructive surgery following quadrantectomy for breast cancer. However, these patients are frequently treated with tamoxifen. We evaluated the ex vivo effects of tamoxifen on ASCs to understand if cellular functions of ASCs are affected. We selected 24 female patients; 10 of which were breast cancer patients treated with quadrantectomy and tamoxifen. As control group, we selected 14 healthy female subjects (9 premenopausal and 5 menopausal). We found that tamoxifen has no effect on cellular proliferation, VEGF secretion or apoptosis of ASCs. The gene expression assessment demonstrated no impairment in differentiation capacity of ASCs. Our results showed that tamoxifen has no effect on cellular functions of ASCs for the first time in an ex vivo single-center study.

microRNA Sequencing of CD34+ Sorted Adipose Stem Cells Undergoing Endotheliogenesis

While several microRNAs (miRNAs) that regulate the endotheliogenesis and further promote angiogenesis have been identified in various cancers, the identification of miRNAs that can drive the differentiation of adipose derived stromal/stem cells (ASCs) into the endothelial lineage has been largely unexplored. In this study, CD34+ ASCs sorted using magnetic bead separation were induced to differentiate along the endothelial pathway. miRNA sequencing of ASCs at day 3, 9, and 14 of endothelial differentiation was performed on Ion Proton sequencing system. The data obtained by this high-throughput method were aligned to the human genome HG38, and the differentially expressed miRNAs during endothelial differentiation at various time points (day 3, 9, and 14) were identified. The gene targets of the identified miRNAs were obtained through miRWalk database. The network-pathway analysis of miRNAs and their targets was performed using the Database for Annotation, Visualization and Integrated Discovery (DAVID) bioinformatic tools to determine the potential candidate miRNAs that promote endothelial differentiation. Based on these analyses, six upregulated miRNAs (miR-181a-5p, miR-330-5p, miR-335-3p, miR-15b-5p, miR-99a-5p, and miR-199a-5p) and six downregulated miRNAs (miR-145-5p, miR-155-5p, miR-193a-3p, miR-125a-5p, miR-221-5p, and miR-222-3p) were chosen for further studies. In vitro evaluation of these miRNAs to induce endothelial differentiation when transfected into CD34+ sorted ASCs was studied using Von Willebrand Factor (VWF) staining and quantitative real time-polymerase chain reaction (qRT-PCR). Our results suggest that miRNAs: 335-5p, 330-5p, 181a-5p and anti-miRNAs: 125a-5p, 145-5p can likely induce endothelial differentiation in CD34+ sorted ASCs. Further studies are clearly required to elucidate the specific mechanisms on how miRNAs or anti-miRNAs identified through bioinformatics approach can induce the endotheliogenesis in ASCs.

Oncologic Safety of Autologous Fat Grafting in Breast Reconstruction

Autologous fat grafting is a useful adjunct to breast reconstruction to address contour changes, volume loss, and deformity. More recent benefits observed include mitigation of pain and inflammation. Although there is no clinical evidence to suggest an increased risk in recurrence or new cancer development in fat grafting for breast reconstruction, the oncologic safety of grafting has come into question. Adipose tissue grafts contain progenitor cells and immunomodulatory cytokines, which may induce vasculogenesis or tumor progression or recurrence at the site. Although these are all theoretical concerns, there is a discrepancy between basic science research and clinical outcomes studies. In this review, the authors summarize available literature regarding three important controversies in fat grafting for oncologic breast reconstruction: the interaction of graft component cells, such as adipose-derived stem cells, with cancer cells; the concern of fat grafting interference with breast cancer screening and detection; and clinical evidence regarding the oncologic safety of fat grafting following breast cancer treatment.

Fat Grafting in Breast Reconstruction

The past two decades have witnessed a growing application of autologous fat grafting in the setting of breast reconstruction after surgical treatment of breast cancer. While traditionally used to correct contour deformities during secondary revisions, fat grafting has since evolved to achieve desired breast shape and size both as a complementary adjunct to established reconstructive techniques as well as a standalone technique for whole breast reconstruction. In this article, we will review fat grafting as an adjunct to autologous and implant-breast based reconstruction, an option for primary breast reconstruction, and a treatment of postmastectomy pain.