MRI evaluation of post-mastectomy irradiated breast implants: prevalence and analysis of complications

The Effects of Radiotherapy on the Sequence and Eligibility of Breast Reconstruction: Current Evidence and Controversy

Immediate breast reconstruction (IBR) following a mastectomy, combined with radiotherapy, presents a multifaceted approach to breast cancer treatment, balancing oncological safety and aesthetic outcomes. IBR, typically involving the use of implants or autologous tissue, aims to restore breast morphology directly after a mastectomy, minimizing the psychological and physical impacts. However, integrating radiotherapy with IBR is complex due to the potential adverse effects on reconstructed tissues. Radiotherapy, essential for reducing local recurrence, can induce fibrosis, capsular contracture, and compromised aesthetic results. This narrative review covers the current trends in the sequencing of breast reconstruction and radiotherapy. We discuss patient selection, timing of radiotherapy, and reconstructive techniques, with special attention paid to quality-of-life outcomes that are increasingly reported in clinical trials. Emerging evidence supports the feasibility of IBR with careful patient selection and tailored therapeutic approaches, although ongoing research is necessary to refine protocols and enhance outcomes. Overall, IBR in the context of radiotherapy remains a promising but intricate treatment modality, requiring a nuanced balance between cancer control and aesthetic restoration.

Reducing Peri-implant Capsule Thickness in Submuscular Rodent Model of Breast Reconstruction With Delayed Radiotherapy

INTRODUCTION

Capsular contracture remains the most common complication following device-based breast reconstruction, occurring in up to 50% of women who also undergo adjuvant radiotherapy either before or after device-based reconstruction. While certain risk factors for capsular contracture have been identified, there remains no clinically effective method of prevention. The purpose of the present study is to determine the effect of coating the implant with the novel small molecule Met-Z2-Y12, with and without delayed, targeted radiotherapy, on capsule thickness and morphologic change around smooth silicone implants placed under the latissimus dorsi in a rodent model.

METHODS

Twenty-four female Sprague Dawley rats each had 2 mL smooth round silicone breast implants implanted bilaterally under the latissimus dorsi muscle. Twelve received uncoated implants and twelve received implants coated with Met-Z2-Y12. Half of the animals from each group received targeted radiotherapy (20 Gray) on postoperative day ten. At three and 6 months after implantation, the tissue surrounding the implants was harvested for analysis of capsular histology including capsule thickness. Additionally, microCT scans were qualitatively analyzed for morphologic change.

RESULTS

Capsules surrounding Met-Z2-Y12-coated implants were significantly thinner (P = 0.006). The greatest difference in capsule thickness was seen in the irradiated 6-month groups, where mean capsule thickness was 79.1 ± 27.3 μm for uncoated versus 50.9 ± 9.6 μm for Met-Z2-Y12-coated implants (P = 0.038). At the time of explant, there were no capsular morphologic differences between the groups either grossly or per microCT.

CONCLUSIONS

Met-Z2-Y12 coating of smooth silicone breast implants significantly reduces capsule thickness in a rodent model of submuscular breast reconstruction with delayed radiotherapy.

An Antifibrotic Breast Implant Surface Coating Significantly Reduces Periprosthetic Capsule Formation

BACKGROUND

The body responds to prosthetic materials with an inflammatory foreign body response and deposition of a fibrous capsule, which may be deleterious to the function of the device and cause significant discomfort for the patient. Capsular contracture (CC) is the most common complication of aesthetic and reconstructive breast surgery. The source of significant patient morbidity, it can result in pain, suboptimal aesthetic outcomes, implant failure, and increased costs. The underlying mechanism remains unknown. Treatment is limited to reoperation and capsule excision, but recurrence rates remain high. In this study, the authors altered the surface chemistry of silicone implants with a proprietary anti-inflammatory coating to reduce capsule formation.

METHODS

Silicone implants were coated with Met-Z2-Y12, a biocompatible, anti-inflammatory surface modification. Uncoated and Met-Z2-Y12-coated implants were implanted in C57BL/6 mice. After 21, 90, or 180 days, periprosthetic tissue was removed for histologic analysis.

RESULTS

The authors compared mean capsule thickness at three time points. At 21, 90, and 180 days, there was a statistically significant reduction in capsule thickness of Met-Z2-Y12-coated implants compared with uncoated implants ( P < 0.05).

CONCLUSIONS

Coating the surface of silicone implants with Met-Z2-Y12 significantly reduced acute and chronic capsule formation in a mouse model for implant-based breast augmentation and reconstruction. As capsule formation obligatorily precedes CC, these results suggest contracture itself may be significantly attenuated. Furthermore, as periprosthetic capsule formation is a complication without anatomical boundaries, this chemistry may have additional applications beyond breast implants, to a myriad of other implantable medical devices.

CLINICAL RELEVANCE STATEMENT

Coating of the silicone implant surface with Met-Z2-Y12 alters the periprosthetic capsule architecture and significantly reduces capsule thickness for at least 6 months postoperatively in a murine model. This is a promising step forward in the development of a therapy to prevent capsular contracture.

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.

Clinical and MRI Evaluation of Silicone Gel Implants with RFID-M Traceability System: A Prospective Controlled Cohort Study Related to Safety and Image Quality in MRI Follow-Up

BACKGROUND

SmoothSilk implants (SSI) are the first generation of implants to incorporate a radio-frequency identification device (RFID-M), a non-invasive traceability system. Although the RFID-M is considered compatible with magnetic resonance imaging (MRI), the size of the artifact and its influence on breast tissue vary. This prospective study assessed safety and MRI issues in a cohort of breast reconstruction patients.

METHODS

Forty-four SSI were used for breast reconstruction in patients undergoing treatment for breast cancer. All patients were evaluated for magnetic field interactions, MRI-related heating and artifacts in a 1.5-T MRI unit using standard T1/T2-weighted sequences utilized in clinical assessment of breast tissue/implants.

RESULTS

Mean patient age was 41.5 years (27-53ys) and body mass index was 28+-6.44 kg/m². In 18/22 patients (81.8%), mastectomies were unilateral. No patients reported local heat/discomfort. All implants showed RFID-M-related artifacts with an estimated mean volume in T1 of 42.9cm³ (26.2-63.6cm³; SD±8.6 and 95% CI, 40.37-45.45) and in T2 of 60.5cm³ (35.4-97.2cm³; SD±14.7 and 95% CI, 56.29-65.01). Artifact volume was smaller in T1 than in T2, to a statistically significant degree (p <0.001). There were no statistically significant differences in artifact volume according to surgical indication, breast side or implant volume. There were 4/44 (9%) cases of minor rotation (<45°). In all cases, adequate analysis of the breast tissue was performed.

CONCLUSIONS

The results demonstrate that SSI with RFID-M technology presented an artifact volume of 42.9cm³ and 60.5cm³ in T1 and T2 images, respectively. Our findings provide detailed information on the quality and location of MRI artifacts in a reconstructed cohort which can help guide clinical decision-making for patients. To our knowledge, this is the first time RFID-M breast implants have been prospectively evaluated for clinical and MRI issues in a cohort of reconstructive patients.

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 .

Periprosthetic Capsule Formation and Contracture in a Rodent Model of Implant-Based Breast Reconstruction With Delayed Radiotherapy

INTRODUCTION

Capsular contracture (CC) is the most common complication of breast implantation, with an incidence of nearly 50% in patients undergoing breast reconstruction with subsequent radiotherapy. Although the move toward submuscular (SM) device placement led to a decreased incidence of CC, subcutaneous (SQ) implantation has seen a resurgence. The purpose of this study was to use a rodent model of breast reconstruction with smooth silicone implants and delayed radiotherapy to assess the occurrence of CC in SQ versus SM implantation.

METHODS

Custom 2 mL smooth round silicone implants were placed bilaterally into 12 female Sprague Dawley rats that were randomized into 4 groups of 3, with each group differing by implantation plane (SQ vs SM) and irradiation status (irradiated vs nonirradiated). Rats from the SQ group received implants bilaterally underlying the skin on the flank. Rats in the SM groups received implants bilaterally under the latissimus dorsi muscle. Irradiated rats received 20 Gy localized to each implant on postoperative day 10. One rat from each group was imaged with a micro-computed tomography scanner at baseline and at explant 3 months later, whereupon capsules from all rats were examined histologically.

RESULTS

Rats in the SQ group showed evidence of contracture on gross examination and greater evidence of morphologic disruption per micro-computed tomography scan. There was no evidence of contracture or morphologic disruption in either SM group. Mean ± SD capsule thickness was 39.0 ± 9.0 μm in the SQ versus 37.6 ± 9.8 μm in the SM nonirradiated groups and 43.9 ± 14.9 μm in the SQ versus 34.3 ± 8.3 μm in the SM irradiated groups (all P > 0.05).

CONCLUSIONS

In a rodent model of smooth silicone breast implantation and delayed radiotherapy, although there did not appear to be differences in capsule thickness regardless of device placement plane, SQ implants demonstrated gross evidence of CC. These data indicate that capsule thickness is only part of a larger pathogenetic picture, which should take into consideration the contribution from all peri-implant tissue.

Breast Reconstruction and Radiation Therapy

Purpose:

The optimal approach to the integration of postmastectomy reconstruction and radiation therapy is not well-established. This review will summarize current literature pertaining to the most common types of reconstruction in the setting of postmastectomy radiation therapy (PMRT).

Data Sources:

Literature from PubMed was reviewed from 2000 to 2016.

Study Selection:

Studies were selected with relevance to “postmastectomy breast reconstruction,” “breast reconstruction,” and “breast reconstructive methods and PMRT.” Surgical outcomes, patient satisfaction, and cost-effectiveness were examined.

Data Extraction:

Data from publications was extracted, summarized, and converted to a table.

Results of Data Synthesis:

Implant-based techniques are on the rise, in the setting of PMRT. Implant-based methods are more affordable in the short term and result in immediate breast-mound formation compared to autologous methods. When compared to implant-based reconstruction with PMRT, autologous reconstruction with PMRT results in better quality of life (QoL) and sensory recovery as well as fewer complications and failures. Among autologous flaps, deep inferior epigastric perforator flaps are considered superior to transverse rectus abdominal muscle (TRAM) pedicled flaps and may be more suitable for PMRT. Latissimus dorsi and muscle-sparing free TRAM flaps are also viable options. In delayed autologous, which may be advantageous for high-risk patients, the optimal timing to delay surgery after radiation therapy is unknown. Reconstruction with a 2-stage tissue expander-implant technique offers good to excellent cosmetic outcomes in the setting of PMRT, although there may be complications in this 2-stage process.

Conclusion:

Surgical, cosmetic, quality of life, and life expectancy must be taken into account when selecting the way to integrate breast reconstruction and PMRT.

Morphologic Features of Magnetic Resonance Imaging as a Surrogate of Capsular Contracture in Breast Cancer Patients With Implant-based Reconstructions

PURPOSE

Capsular contracture (CC) is a serious complication in patients receiving implant-based reconstruction for breast cancer. Currently, no objective methods are available for assessing CC. The goal of the present study was to identify image-based surrogates of CC using magnetic resonance imaging (MRI).

METHODS AND MATERIALS

We analyzed a retrospective data set of 50 patients who had undergone both a diagnostic MRI scan and a plastic surgeon's evaluation of the CC score (Baker's score) within a 6-month period after mastectomy and reconstructive surgery. The MRI scans were assessed for morphologic shape features of the implant and histogram features of the pectoralis muscle. The shape features, such as roundness, eccentricity, solidity, extent, and ratio length for the implant, were compared with the Baker score. For the pectoralis muscle, the muscle width and median, skewness, and kurtosis of the intensity were compared with the Baker score. Univariate analysis (UVA) using a Wilcoxon rank-sum test and multivariate analysis with the least absolute shrinkage and selection operator logistic regression was performed to determine significant differences in these features between the patient groups categorized according to their Baker's scores.

RESULTS

UVA showed statistically significant differences between grade 1 and grade ≥2 for morphologic shape features and histogram features, except for volume and skewness. Only eccentricity, ratio length, and volume were borderline significant in differentiating grade ≤2 and grade ≥3. Features with P<.1 on UVA were used in the multivariate least absolute shrinkage and selection operator logistic regression analysis. Multivariate analysis showed a good level of predictive power for grade 1 versus grade ≥2 CC (area under the receiver operating characteristic curve 0.78, sensitivity 0.78, and specificity 0.82) and for grade ≤2 versus grade ≥3 CC (area under the receiver operating characteristic curve 0.75, sensitivity 0.75, and specificity 0.79).

CONCLUSIONS

The morphologic shape features described on MR images were associated with the severity of CC. MRI has the potential to further improve the diagnostic ability of the Baker score in breast cancer patients who undergo implant reconstruction.