Role of Mitomycin C in Preventing Capsular Contracture in Implant-Based Reconstructive Breast Surgery: A Randomized Controlled Trial

A systematic review of randomised controlled trials in breast reconstruction

BACKGROUND

For preference sensitive treatments, such as breast reconstructions, there are barriers to conducting randomised controlled trials (RCTs). The primary aims of this systematic review were to investigate what type of research questions are explored by RCTs in breast reconstruction, where have they been performed and where have they been published, and to thematise the research questions and thus create an overview of the state of the research field.

METHODS

Randomised controlled trials investigating any aspect of breast reconstructions were included. The PubMed database was searched with a pre-defined search string. Inclusion and data abstraction was performed in a pre-defined standardised fashion. For the purpose of this study, we defined key issues as comparison of categories of breast reconstruction and comparison of immediate and delayed breast reconstruction, when the thematisation was done.

RESULTS

A total of 419 abstracts were retrieved from the search. Of the 419, 310 were excluded as they were not RCTs concerning some aspect of breast reconstruction, which left us with 110 abstracts to be included in the study. The research questions of the included studies could more or less be divided into seven different themes inclusive of 2 key issues: Other issues - comparison of different categories of breast reconstruction, comparison of immediate and delayed breast reconstruction, surgical details within a category of breast reconstruction, surgical details valid for several categories of breast reconstruction, donor site management, anaesthetics, and non-surgical details. Only five studies compared key issues, and they all illustrate the challenges with RCTs in breast reconstruction.

CONCLUSIONS

A total of 110 publications based on RCTs in breast reconstruction have been published. Seven themes of research questions could be identified. Only five studies have explored the key issues. Better scientific evidence is needed for the key issues in breast reconstruction, for example by implementing a new study design in the field.

"Spin" in Plastic Surgery Randomized Controlled Trials with Statistically Nonsignificant Primary Outcomes: A Systematic Review

BACKGROUND

"Spin" refers to a manipulation of language that implies benefit for an intervention when none may exist. Randomized controlled trials (RCTs) in other fields have been demonstrated to employ spin, which can mislead clinicians to use ineffective or unsafe interventions. This study's objective was to determine the strategies, severity, and extent of spin in plastic surgery RCTs with nonsignificant primary outcomes.

METHODS

A literature search of the top 15 plastic surgery journals using MEDLINE was performed (2000 through 2020). Parallel 1:1 RCTs with a clearly identified primary outcome showing statistically nonsignificant results ( P > 0.05) were included. Screening, data extraction, and spin analysis were performed by two independent reviewers. The spin analysis was then independently assessed in duplicate by two plastic surgery residents with graduate-level training in clinical epidemiology.

RESULTS

From 3497 studies identified, 92 RCTs were included in this study. Spin strategies were identified in 78 RCTs (85%), including 64 abstracts (70%) and 77 main texts (84%). Severity of spin was rated moderate or high in 43 abstract conclusions (47%) and 42 main text conclusions (46%). The most identified spin strategy in the abstract was claiming equivalence for statistically nonsignificant results (26%); in the main text, focusing on another objective (24%).

CONCLUSIONS

This study suggests that 85% of statistically nonsignificant RCTs in plastic surgery employ spin. Readers of plastic surgery research should be aware of strategies, whether intentional or unintentional, used to manipulate language in reports of statistically nonsignificant RCTs when applying research findings to clinical practice.

Comparison of nine methods of immediate breast reconstruction after resection of localized breast cancer: A cost-effectiveness Markov decision analysis of prospective studies

BACKGROUND

Women undergoing immediate breast reconstruction without radiation therapy have reconstruction methods available with uncertain long-term costs associated with complications requiring surgery and revisions. We evaluated cost-effectiveness of nine methods of immediate breast reconstruction for women with localized breast cancer.

METHODS

Markov modeling was performed over 10-years for unilateral/bilateral breast reconstructions from healthcare/societal perspectives. PubMed, Embase, Cochrane, Scopus, and CINAHL were searched to derive data from 13,744 patients in 79 prospective studies. Complications requiring surgery (mastectomy necrosis, total/partial flap necrosis, seroma, hematoma, infection, wound dehiscence, abdominal hernia, implant removal/explantation) and revisions (fat necrosis, capsular contracture, asymmetry, scars/redundant tissue, implant rupture/removal, fat grafting) were evaluated over yearly cycles. Reconstructions included: direct-to-implant (DTI), tissue expander-to-implant (TEI), latissimus dorsi flap-to-implant (LDI), latissimus dorsi (LD), pedicled transverse rectus abdominis myocutaneous (TRAM), free TRAM, deep inferior epigastric perforator/superficial inferior epigastric artery (DIEP/SIEA), thigh-based, or gluteal based flaps. Outcomes were incremental cost-effectiveness ratios (ICER) and net monetary benefits (NMB). Willingness-to-pay thresholds were $50,000 and $100,000.

RESULTS

From a healthcare perspective for unilateral reconstruction, compared to LD, the ICER for DTI was -$42,109.35/quality-adjusted life-years (QALY), LDI was -$25,300.83/QALY, TEI was -$22,036.02/QALY, DIEP/SIEA was $8307.65/QALY, free TRAM was $8677.26/QALY, pedicled TRAM was $13,021.44/QALY, gluteal-based was $17,698.99/QALY, and thigh-based was $23,447.82/QALY. NMB of DIEP/SIEA was $404,523.47, free TRAM was $403,821.40, gluteal-based was $392,478.64, thigh-based was $387,691.70, pedicled TRAM was $376,901.83, LD was $370,646.93, DTI was $339,668.77, LDI was $334,350.30, and TEI was $329,265.84.

CONCLUSIONS

All nine methods of immediate breast reconstruction were considered cost-effective from healthcare/societal perspectives. LD provided the lowest costs, while DIEP/SIEA provided the greatest effectiveness and NMB.

Capsular Contracture in Breast Implant Surgery: Where Are We Now and Where Are We Going?

Capsular contracture is the leading complication after surgery with breast implants. A lot of progress has been made investigating this complication over the years, and knowledge has been gained on this complication. Currently, the exact cause for capsular contracture is still unclear. It has been hypothesized that immunobiological factors (i.e., immunological and bacterial factors) and several risk factors play a central role in its development. In this paper, we give an overview of the known immunological factors that have been investigated in contracted and non-contracted capsules, as well as the role of bacterial formation around breast implants. We also report on risk factors that might increase the risk of capsular development. Lastly, it provides the latest research on this matter and discusses future perspectives as follow-up research is needed to unravel the pathogenic process leading to capsular contracture. This knowledge is of interest to establish medical therapies in order to prevent such side effects. Overall, capsular contracture seems to be a multifactorial condition consisting of several risk factors. 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 .

Pro-Fibrotic CD26-Positive Fibroblasts Are Present in Greater Abundance in Breast Capsule Tissue of Irradiated Breasts

BACKGROUND

Breast capsular contracture is a major problem following implant-based breast reconstruction, particularly in the setting of radiation therapy. Recent work has identified a fibrogenic fibroblast subpopulation characterized by CD26 surface marker expression.

OBJECTIVES

This work aimed to investigate the role of CD26-positive fibroblasts in the formation of breast implant capsules following radiation therapy.

METHODS

Breast capsule specimens were obtained from irradiated and nonirradiated breasts of 10 patients following bilateral mastectomy and unilateral irradiation at the time of expander-implant exchange, under institutional review board approval. Specimens were processed for hematoxylin and eosin staining as well as for immunohistochemistry and fluorescence activated cell sorting for CD26-positive fibroblasts. Expression of fibrotic genes and production of collagen were compared between CD26-positive, CD26-negative, and unsorted fibroblasts.

RESULTS

Capsule specimens from irradiated breast tissue were thicker and had greater CD26-postive cells on immunofluorescence imaging and on fluorescence activated cell sorting analysis than did capsule specimens from the nonirradiated breast. Compared with CD26-negative fibroblasts, CD26-positive fibroblasts produced more collagen and had increased expression of the profibrotic genes IL8, TGF-β1, COL1A1, and TIMP4.

CONCLUSIONS

CD26-positive fibroblasts were found in a significantly greater abundance in capsules of irradiated compared with nonirradiated breasts and demonstrated greater fibrotic potential. This fibrogenic fibroblast subpopulation may play an important role in the development of capsular contracture following irradiation, and its targeted depletion or moderation may represent a potential therapeutic option.

LEVEL OF EVIDENCE: 2

Intra-articular injection of mitomycin C prevents progression of immobilization-induced arthrogenic contracture in the remobilized rat knee

This study tested whether cell cycle inhibitor mitomycin C (MMC) prevents arthrogenic contracture progression during remobilization by inhibiting fibroblast proliferation and fibrosis in the joint capsule. Rat knees were immobilized in a flexed position to generate flexion contracture. After three weeks, the fixation device was removed and rat knees were allowed to freely move for one week. Immediately after and three days after fixator removal, rats received intra-articular injections of MMC or saline. The passive extension range of motion (ROM) was measured before and after myotomy of the knee flexors to distinguish myogenic and arthrogenic contractures. In addition, both cellularity and fibrosis in the posterior joint capsule were assessed histologically. Joint immobilization significantly decreased ROMs both before and after myotomy compared with untreated controls. In saline-injected knees, remobilization increased ROM before myotomy, but further decreased that after myotomy compared with that of knees immediately after three weeks of immobilization. Histological analysis revealed that hypercellularity, mainly due to fibroblast proliferation, and fibrosis characterized by increases in collagen density and joint capsule thickness occurred after remobilization in saline-injected knees. Conversely, MMC injections were able to prevent the remobilization-enhanced reduction of ROM after myotomy by inhibiting both hypercellularity and joint capsule fibrosis. Our results suggest that joint capsule fibrosis accompanied by fibroblast proliferation is a potential cause of arthrogenic contracture progression during remobilization, and that inhibiting fibroblast proliferation may constitute an effective remedy.

Current Approaches Including Novel Nano/Microtechniques to Reduce Silicone Implant-Induced Contracture with Adverse Immune Responses

Capsular contracture, which is the pathologic development of fibrous capsules around implants, is a major complication of reconstructive and aesthetic breast surgeries. Capsular contracture can cause implant failure with breast hardening, deformity, and severe pain. The exact mechanisms underlying this complication remain unclear. In addition, anaplastic large cell lymphoma is now widely recognized as a very rare disease associated with breast implants. Foreign body reactions are an inevitable common denominator of capsular contracture. A number of studies have focused on the associated immune responses and their regulation. The present article provides an overview of the currently available techniques, including novel nano/microtechniques, to reduce silicone implant-induced contracture and associated foreign body responses.