Fat Graft Safety after Oncologic Surgery: Addressing the Contradiction between In Vitro and Clinical Studies

Oncological Safety of Autologous Fat Grafting for Breast Reconstruction

BACKGROUND

Autologous fat grafting has become a vital component of breast reconstruction. However, concerns remain regarding the safety of fat grafting after oncological resection and breast reconstruction. The purpose of the study was to evaluate the association of fat grafting after breast reconstruction with metastasis and death in breast cancer patients.

METHODS

A retrospective, population-based cohort study was conducted using deidentified claims data from 2001 to 2018 and included privately insured patients with breast cancer who underwent breast reconstruction after surgical resection. Breast reconstruction patients who underwent fat grafting were compared with those not undergoing fat grafting, evaluating metastasis and death up to 15 years after reconstruction. One-to-one propensity score matching was used to account for selection bias on patient risk factors comparing those with and without fat grafting.

RESULTS

A total of 4709 patients were identified who underwent breast reconstruction after lumpectomy or mastectomy, of which 368 subsequently underwent fat grafting. In the propensity score-matched patients, fat grafting was not associated with an increased risk of lymph node metastasis (9.7% fat-grafted vs 11.4% in non-fat-grafted, P = 0.47) or distant metastasis (9.1% fat-grafted vs 10.5% in non-fat-grafted, P = 0.53). There was no increased risk of all-cause mortality after fat grafting for breast reconstruction (3.9% fat-grafted vs 6.6% non-fat-grafted, P = 0.10).

CONCLUSIONS

Among breast cancer patients who subsequently underwent fat grafting, compared with no fat grafting, no significant increase was observed in distant metastasis or all-cause mortality. These findings suggest that autologous fat grafting after oncologic resection and reconstruction was not associated with an increased risk of future metastasis or death.

Meta-Analysis of the Oncological Safety of Autologous Fat Grafting After Breast Cancer on Basic Science and Clinical Studies

BACKGROUND

The purpose of the present study was to comprehensively evaluate the oncological safety of autologous fat grafting after breast cancer by combining experimental and clinical studies.

METHODS

All studies published before August 2021 were collected by searching PubMed, Cochrane, Embase, Web of Science, SINOMED, and China National Knowledge Infrastructure. After screening the research and extracting the data, RevMan was used to perform the meta-analysis.

RESULTS

Five basic science studies and 26 clinical studies, involving a total of 10,125 patients, were eventually included. In the basic science studies, adipose-derived stem cells promoted breast cancer growth, but fat grafting and adipose-derived stem cells plus fat grafting were not associated with breast cancer growth. An overall analysis of clinical studies showed that autologous fat grafting does not increase the risk of breast cancer recurrence. Subgroup analyses indicated that autologous fat grafting did not increase the risk of breast cancer recurrence in Asian or Caucasian patients, in patients undergoing breast-conserving surgery or modified radical mastectomy, in patients with in situ carcinomas or invasive carcinomas, or in patients undergoing postoperative radiotherapy.

CONCLUSION

This study combined experimental and clinical studies to conclude that autologous fat grafting does not increase the risk of breast cancer recurrence. However, the experimental results suggest that adipose-derived stem cells should be used with caution after breast cancer surgery.

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 .

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 .

Oncologic safety of breast reconstruction with autologous fat grafting: A systematic review and meta-analysis

BACKGROUND

Autologous fat grating has become increasingly popular as a breast reconstructive procedure. Nevertheless, preclinical studies show that fat transfer to a previous breast cancer site could activate latent cancer cells, creating a favourable environment for disease recurrence. A systematic review and meta-analysis was performed to investigate whether fat grafting increases the risk of locoregional recurrence in patients formerly treated for breast cancer.

METHODS

Based on PRISMA guidelines, a systematic review searching for randomised clinical trials and matched cohorts on the topic was performed in the electronic databases Pubmed, Embase, Web of Science, and Cochrane. The date of the last search was July 20, 2021. The meta-analysis assessed the comparison of locoregional recurrence between groups.

RESULTS

From a total of 558 publications, data from nine matched cohorts (1.6%) reporting on 4247 subjects (1590 and 2657 subjects, respectively, in lipofilling and control groups) were suitable for inclusion in the meta-analysis. Neither of the outcomes had a statistically significant difference for disease recurrence. For the primary outcome, comparing locoregional recurrence rates between groups, the incidence rate ratio was 0.92 (95% CI: 0.68-1.26; P = 0.620).

CONCLUSION

The present meta-analysis, which comprises the outcomes of the individual studies with the best current evidence on the topic so far, strengthens the evidence favouring the oncologic safety of lipofilling for breast reconstruction.

Treating Anisomastia and Tuberous Breast with Fat Grafting: Technique and Evaluation of Outcomes Using BREAST-Q Surveys

BACKGROUND

In the surgical correction of tuberous breast deformity, implants and regional flaps play a prominent role. Lately, fat grafting has been used as an alternative, but there is evidence that patient satisfaction is higher after correction with implants compared with lipofilling.

METHODS

We report a tuberous breasts correction series of ten cases, enrolled between 2015 and 2018. Percutaneous fasciotomies and fat grafting were performed by the Body-Jet technique. Analysis of outcomes was undertaken with BREAST-Q surveys.

RESULTS

The breast satisfaction scores increased from 0 to 75 (p < 0.01), the psychological well-being scores from 20 to 70 (p < 0.01) and the sexual well-being scores from 18.5 to 58 (p = 0.02), while the physical well-being scores remained stable (from 68 to 63, p = 0.2). The median outcome satisfaction score was 86.

CONCLUSION

Scores of patient-reported outcomes after lipofilling can reach and even exceed those of patients corrected with implants, at the cost of more interventions. Fat grafting is beginning to establish itself as a true alternative in the treatment of tuberous breast deformity in patients with the appropriate fat deposits.

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 Table of Contents or online Instructions to Authors www.springer.com/00266 .

Autologous Fat Grafting Does Not Increase Risk of Oncologic Recurrence in the Reconstructed Breast

INTRODUCTION

Autologous fat grafting (AFG) is a popular and effective method of breast reconstruction after mastectomy; however, the oncological safety of AFG remains in question. The aim of this study was to determine whether AFG increases the risk of cancer recurrence in the reconstructed breast.

METHODS

A matched, case-control study was conducted from 2000 to 2017 at the senior author's institution. Inclusion was limited to female patients who underwent mastectomy and breast reconstruction with or without AFG. Data were further subdivided at the breast level. χ analyses were used to test the association between AFG status and oncologic recurrence. A Cox proportional-hazards model was constructed to assess for possible differences in time to oncologic recurrence. The probability of recurrence was determined by Kaplan-Meier analyses and confirmed with log-rank testing.

RESULTS

Overall, 428 breasts met study criteria. Of those, 116 breasts (27.1%) received AFG, whereas 312 (72.9%) did not. No differences in the rates of oncologic recurrence were found between the groups (8.2% vs 9.0%, P < 1.000). Unadjusted (hazard ratio = 1.03, confidence interval = 0.41-2.60, P < 0.957) and adjusted hazard models showed no statistically significant increase in time to oncologic recurrence when comparing AFG to non-AFG. In addition, no statistical differences in disease-free survival were found (P = 0.96 by log rank test).

CONCLUSION

Autologous fat grafting for breast reconstruction is oncologically safe and does not increase the likelihood of oncologic recurrence. Larger studies (eg, meta analyses) with longer follow-up are needed to further elucidate the long-term safety of AFG as a reconstructive adjunct.

Phenotypic and Cellular Characteristics of a Stromal Vascular Fraction/Extracellular Matrix Gel Prepared Using Mechanical Shear Force on Human Fat

The retention of fat-derived grafts remains a challenge for regenerative medicine. Fat aspirates from patients undergoing liposuction were prepared into standard Coleman fat grafts or further isolated using mechanical shear force to prepare a stromal vascular fraction (SVF)/extracellular matrix (ECM) gel. The retention rate of the SVF/ECM gel was significantly higher than that of the Coleman fat at 3, 14, 28, and 60 days following transplantation on the backs of nude mice. The viscosity of the fat was directly proportional to the shearing force. Although the mechanical isolation did not affect the total number of cells, it significantly decreased the number of living cells. Flow cytometry showed a greater number of mesenchymal stem cells, supra-adventitial (SA)-adipose stromal cells (ASCs), and adipose-derived stem cells but a lower number of endothelial progenitor cells in the SVF/ECM gel than in the Coleman fat. Thus, mechanical isolation of fat can increase the pluripotency of adipocytes, which can improve graft retention in cell therapy.

Microenvironmental Changes in the Surviving Fat 1 Year After Autologous Fat Transplantation for Breast Augmentation

BACKGROUND

Autologous fat is currently one of the most commonly used soft tissue materials in plastic surgery, but the changes that occur in fat after transplantation are unclear. Existing studies on the changes in surviving fat mostly involve animal experiments.

OBJECTIVES

The aim of this study was to obtain surviving fat 1 year after clinical autologous fat transplantation for breast augmentation, to explain the microenvironmental changes after fat transplantation from a clinical perspective, and to verify previous research conclusions, thus providing new insight into fat survival.

METHODS

Samples of surviving fat were obtained from 5 patients 1 year after they had undergone autologous fat transplantation for breast augmentation, and normal fat samples were obtained from 5 patients who had not undergone this procedure. The differences between CD68 and CD31 were analyzed immunohistochemically, and between CD34 and Ki67 by immunofluorescence. We also tested whether UCP-1 is expressed in surviving fat.

RESULTS

The relative CD68, CD34, and Ki67 expression levels in the surviving fat tissue were significantly higher than those in the normal fat tissue (PCD68 = 0.04, PCD34 = 0.03, PKi67 = 0.02). The relative CD31 expression was not significantly different between the two groups (P = 0.52). No UCP-1 expression was observed in any surviving fat tissue.

CONCLUSIONS

Chronic inflammatory reactions mediated by macrophages were detectable 1 year after autologous fat transplantation for breast augmentation. The mesenchymal stem cell content in surviving fat was higher than that in normal fat, but the number of blood vessels was close to that in normal breast fat tissue. No genesis of brown fat was found.

LEVEL OF EVIDENCE: 5

Analysis of oncological safety of autologous fat grafting after immediate breast reconstruction

Background

Fat grafting is now a common procedure for breast reconstruction. Many clinical studies have reported its aesthetic efficacy and oncological safety, but some experimental studies raise about the recurrence risk because of its regenerating property. This study aims to investigate the possibility of cancer recurrence associated with fat grafting.

Methods

In this retrospective cohort study, we analyzed a total of 339 patients who had undergone immediate reconstructive surgery after nipple-sparing mastectomy (NSM) or skin-sparing mastectomy (SSM) in our institution between February 28, 2009 and March 23, 2019. Patients who had undergone breast conserving surgery, radical mastectomy, or delayed reconstruction were excluded. We used univariate and multivariate Cox proportional hazards regression models to evaluate the association between fat grafting and cancer recurrence.

Results

Among the 339 patients during a median follow-up of 52 months, 27 patients (8.0%) were confirmed to have recurrent cancer. Of 67 patients who had undergone fat grafting, 10 patients were confirmed to have cancer recurrence. In multivariate analyses, fat grafting [hazard ratio (HR), 2.52; 95% CI, 1.005-6.317; P=0.0488] was independently associated with cancer recurrence.

Conclusions

In population of breast cancer patient who underwent immediate reconstruction in our institution, fat grafting showed significant higher risk of cancer recurrence. Although these results are at odds with many existing studies, it suggests that more careful follow-up may be necessary for patients who had undergone fat grafting after reconstructive surgery.

The Impact of Human Lipoaspirate and Adipose Tissue-Derived Stem Cells Contact Culture on Breast Cancer Cells: Implications in Breast Reconstruction

BACKGROUND

Autologous fat transfer in the form of lipoaspirates for the reconstruction of the breast after breast cancer surgery is a commonly used procedure in plastic surgery. However, concerns regarding the oncologic risk of nutrient-rich fat tissue are widely debated. Previous studies have primarily focused on studying the interaction between adipose-derived stem cells (ASCs) and breast cancer cells.

METHODS

In this study, we performed a comprehensive analysis of the paracrine- and contact-based interactions between lipoaspirates, ASCs and breast cancer cell lines. An inverted flask culture method was used to study the contact-based interaction between lipoaspirates and breast cancer cells, while GFP-expressing breast cancer cell lines were generated to study the cell-cell contact interaction with ASCs. Three different human breast cancer cell lines, MCF-7, MDA-MB-231 and BT-474, were studied. We analyzed the impact of these interactions on the proliferation, cell cycle and epithelial-to-mesenchymal (EMT) transition of the breast cancer cells.

RESULTS

Our results revealed that both lipoaspirates and ASCs do not increase the proliferation rate of the breast cancer cells either through paracrine- or contact-dependent interactions. We observed that lipoaspirates selectively inhibit the proliferation of MCF-7 cells in contact co-culture, driven by the retinoblastoma (Rb) protein activity mediating cell cycle arrest. Additionally, ASCs inhibited MDA-MB-231 breast cancer cell proliferation in cell-cell contact-dependent interactions. Quantitative real-time PCR revealed no significant increase in the EMT-related genes in breast cancer cells upon co-culture with ASCs.

CONCLUSION

In conclusion, this study provides evidence of the non-oncogenic character of lipoaspirates and supports the safety of clinical fat grafting in breast reconstruction after oncological surgical procedures. In vivo studies in appropriate animal models and long-term post-operative clinical data from patients are essential to reach the final safety recommendations.

The safety and efficacy of autologous fat grafting during second stage breast reconstruction

BACKGROUND

Patients often pursue revisions following implant-based breast reconstruction (IBR) to achieve their desired result. Fat grafting is a popular choice for patients and can be performed at second stage reconstruction or at a future date as a revisionary surgery. We investigate the best time to fat graft in IBR by comparing the outcomes of patients who received fat grafting during implant placement with those who pursued fat grafting during a tertiary procedure.

METHODS

We retrospectively reviewed the charts of 157 patients (270 breasts) who underwent immediate two-stage IBR and fat grafting over a five-year period (2012-2016) at our institution. Two cohorts were created based on timing of first fat grafting procedure: immediate (IFG) and delayed (DFG). Charts were reviewed for postoperative complications or revisions.

RESULTS

Complication rates were lower when fat grafting was performed during the second stage (p = 0.0331). Patients in the DFG cohort required more than one additional revision (p < 0.001) until the completion of reconstruction. Patients in the IFG cohort completed their reconstruction and revisions more than one year earlier than the DFG cohort (p < 0.001). Multivariable regressions showed IFG to be associated with decreased revisions (p < 0.001) and total fat grafting procedures (p = 0.008).

CONCLUSIONS

These results indicate that fat grafting at the second stage does not increase overall complication rates, require fewer additional surgeries, and enables patients to reach their desired aesthetic appearance in a shorter time frame. Fewer total surgeries translate not only to a more economical option but also obviate the risk of complications that come with additional surgeries.

Fat grafts enriched with adipose-derived stem cells

Autologous fat grafts are widely used in soft-tissue augmentation and reconstruction. To reduce the unpredictability of fat grafts and to improve their long-term survival, cell-assisted lipotransfer (CAL) was introduced. In this alternative method, autologous fat is mixed and grafted with stromal vascular fraction cells or adipose-derived stem/stromal cells (ASCs). In regenerative medicine, ASCs exhibit excellent therapeutic potential and are also simple to harvest. Although the efficacy of CAL has been demonstrated in experimental and clinical research, studies on its safety in terms of oncologic risk have reported inconclusive results. In order to establish CAL as a viable stem cell therapeutic approach, it will be necessary to demonstrate its oncologic safety in basic and clinical studies. Doing so could transform the paradigm of clinical strategy and practice for the treatment of a wide variety of diseases.

Tissue engineering in female pelvic floor reconstruction

Pelvic organ prolapse is a common and frequently occurring disease in middle-aged and elderly women. Mesh implantation is an ideal surgical treatment. The polypropylene mesh commonly used in clinical practice has good mechanical properties, but there are long-term complications. The application of tissue engineering technology in the treatment of pelvic organ prolapse disease can not only meet the mechanical requirements of pelvic floor support, but also be more biocompatible than traditional polypropylene mesh, and can promote tissue repair to a certain extent. In this paper, the progress of tissue engineering was summarized to understand the application of tissue engineering in the treatment of pelvic organ prolapse disease and will help in research.

Safety and Regulation of Fat Grafting

Today, fat grafting has wide applicability across plastic surgery disciplines, including both aesthetic and reconstructive procedures. However, much controversy has surrounded adipose tissue transfer throughout the 20th century, necessitating extensive research to improve the fat grafting process and to better understand its associated complications and benefits. Initial concerns included the technical difficulties of properly handling and processing adipose to ensure adequate outcomes. As these issues were addressed, more modern concerns were raised by the U.S Food and Drug Administration and the general scientific community regarding the oncological potential of adipose tissue and its potential interference with breast cancer screenings. Today, many formalized clinical studies have evidenced the safety of fat grafting, allowing the procedure to gain widespread popularity and opening avenues for future applications.

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.

The use of autologous fat grafts in breast surgery: A literature review

Autologous fat injection was first described roughly a century ago and has been used in surgery ever since. In addition to its use in many surgical fields, it is also frequently used for both aesthetic and reconstructive purposes in breast surgery. Since the application of fat grafting in breast surgery has steadily increased, studies investigating its reliability have simultaneously become increasingly common. Previous studies have reported that the use of fat grafting in breast surgery is reliable, but some pending questions remain about its routine use. In order to use fat grafts successfully in breast surgery, it is necessary to be familiar with the structure and content of adipose tissue, the efficacy of adipose stem cell-enriched fat grafts, the oncological safety of fat grafts, and the problems that may occur in the radiological follow-up of patients who undergo fat grafting procedures. In this literature review, we aim to discuss the use of fat grafts in breast surgery by investigating these common problems.