Early outcomes of volume replacement using paste-type micronized acellular dermal matrix in oncoplastic breast-conserving surgery
Youn Jung Cha
, Eun Hwa Park
Contributions: (I) Conception and design: Both authors; (II) Administrative support: EH Park; (III) Provision of study materials or patients: Both authors; (IV) Collection and assembly of data: Both authors; (V) Data analysis and interpretation: Both authors; (VI) Manuscript writing: Both authors; (VII) Final approval of manuscript: Both authors.
Background: Surgical approaches in breast cancer have evolved to balance oncologic safety with cosmetic outcomes. Oncoplastic breast-conserving surgery (BCS) was developed to overcome the cosmetic limitations of conventional BCS and has been widely adopted in breast cancer treatment. Although the concept of oncoplastic BCS has been established for decades, breast and plastic surgeons continue to refine surgical techniques to achieve oncologic outcomes that are not inferior while improving aesthetic results. Therefore, this study aimed to evaluate the early postoperative outcomes and safety of oncoplastic BCS using paste-type micronized acellular dermal matrix (ADM) for volume replacement.
Methods: This retrospective chart review included 167 female patients who underwent BCS at a single institution between February 2021 and May 2023. Patients were divided into two groups: BCS only (n=94) and BCS with volume replacement using paste-type micronized ADM (n=73). The decision to use ADM was made intraoperatively based on anticipated contour deformity after tumor excision, considering tumor location, defect size, and tissue characteristics, as well as patient preference. To adjust for baseline differences between groups, inverse probability of treatment weighting (IPTW) analysis was performed. Clinicopathologic characteristics, operative variables, and postoperative outcomes were analyzed.
Results: Baseline clinicopathologic characteristics were initially imbalanced between the groups; however, after IPTW adjustment, variables including age and tumor characteristics were well balanced between the two groups. The mean operative time did not differ significantly between the BCS-only group and the ADM group (83.0 vs. 83.6 minutes). Minor postoperative complications were infrequent and included seroma and hematoma, all of which were managed conservatively or with minimal intervention. One patient in the ADM group developed wound dehiscence with associated postoperative infection and subsequently required ADM removal. No cases of red breast syndrome were observed. Cosmetic outcomes were generally acceptable in both groups during early follow-up. Postoperative imaging demonstrated no suspicious findings suggestive of recurrence during early follow-up.
Conclusions: Oncoplastic BCS with volume replacement using paste-type micronized ADM appears to be a safe and technically feasible option with comparable early postoperative outcomes. Given the retrospective design and limited follow-up, further prospective studies with standardized cosmetic assessment and longer follow-up are required to clarify long-term outcomes.
Keywords: Breast-conserving surgery (BCS); oncoplastic surgery; acellular dermal matrix (ADM); volume replacement; cosmetic outcome
Submitted Jan 06, 2026. Accepted for publication Mar 20, 2026. Published online Apr 26, 2026.
doi: 10.21037/gs-2026-1-0002
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Key findings
• Volume replacement using paste-type micronized acellular dermal matrix (ADM) in oncoplastic breast-conserving surgery (BCS) was technically simple and did not significantly prolong operative time.
• Early postoperative complications were infrequent, and favorable early cosmetic outcomes were observed in patients who underwent ADM-assisted reconstruction.
• Postoperative imaging demonstrated minimal radiologic ambiguity at the ADM-inserted site, facilitating follow-up surveillance.
What is known and what is new?
• Oncoplastic BCS aims to achieve oncologic safety while preserving breast aesthetics.
• ADM has been widely used in implant-based breast reconstruction, primarily as a supportive material rather than for direct volume replacement.
• The role of ADM for volume replacement in BCS remains limited and controversial.
What is the implication, and what should change now?
• Paste-type micronized ADM may be considered a useful adjunct for volume replacement in selected patients undergoing oncoplastic BCS, particularly when aesthetic preservation is a priority.
• The injectable nature of micronized ADM allows flexible intraoperative contour correction and may offer advantages in postoperative imaging follow-up.
Introduction
Background
Surgical approaches in breast cancer have evolved to balance oncologic safety with cosmetic outcomes. Oncoplastic breast-conserving surgery (BCS) was developed to overcome the cosmetic limitations of conventional BCS and has been widely adopted in breast cancer treatment. Although the concept of oncoplastic BCS has been established for decades, breast and plastic surgeons continue to refine surgical techniques to achieve oncologic outcomes that are not inferior while improving aesthetic results (1-4).
Oncoplastic BCS can be broadly categorized into volume displacement and volume replacement techniques (5). In Asian women, smaller breast volume combined with relatively larger tumor size often makes volume displacement using autologous tissue insufficient to achieve satisfactory cosmetic outcomes. In patients with small- to medium-sized breasts, volume replacement techniques have been reported to yield superior aesthetic results (6-8). However, in cases with relatively large defects or tumors located in cosmetically sensitive areas, parenchymal rearrangement alone may be insufficient to prevent contour deformity.
Volume replacement can be achieved using either autologous tissue or biomaterials. Acellular dermal matrix (ADM) is available in several forms, including sheet-type, diced-type, and micronized-type. In breast cancer surgery, sheet-type ADM has been predominantly used, mainly as structural support for implants in post-mastectomy reconstruction rather than for direct volume replacement (9). ADM is a biologic collagen matrix that has been used in various reconstructive procedures due to its favorable integration with host tissue (10,11).
Several studies have reported the use of sheet-type or diced-type ADM for volume replacement in oncoplastic BCS (12-14). However, clinical evidence regarding the use of paste-type micronized ADM for volume replacement in oncoplastic BCS remains limited, particularly in terms of early postoperative outcomes and safety. Therefore, this study aimed to evaluate the early postoperative outcomes and safety of oncoplastic BCS using paste-type micronized ADM for volume replacement. We present this article in accordance with the STROBE reporting checklist (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0002/rc).
Methods
Patients
From February 2021 to May 2023, a total of 167 female patients with breast cancer who underwent BCS at a single institution were retrospectively reviewed through chart analysis. Patients were divided into two groups: 94 patients who underwent BCS alone and 73 patients who underwent BCS with volume replacement using paste-type micronized ADM.
To minimize selection bias, consecutive patients undergoing BCS during the study period were included. The decision to use paste-type micronized ADM was made intraoperatively based on the anticipated contour deformity after tumor excision and parenchymal rearrangement, considering factors such as tumor location, defect size, and tissue characteristics. Patient preference was also considered, and ADM was not used when patients declined its use.
Demographic characteristics, tumor stage, tumor type and location, pathological tumor size, resection volume, operative time, and postoperative outcomes were collected from medical records. Some patients received neoadjuvant chemotherapy prior to surgical treatment.
To adjust for baseline differences between the two groups, inverse probability of treatment weighting (IPTW) analysis was performed. No missing data were identified for the variables analyzed.
This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of Dong-A University Hospital (IRB No. DAUHIRB-23-219), and the requirement for informed consent was waived due to the retrospective nature of the study.
Surgical technique
BCS was performed through a 3–5 cm skin incision. Partial breast tissue including the tumor was excised, and resection margins were confirmed intraoperatively using frozen-section biopsy. After confirmation of negative margins, the surgeon determined whether volume replacement with ADM was necessary based on the anticipated postoperative breast contour, considering tumor location, defect size, and tissue characteristics. Patient preference was also considered, and ADM was not used when patients declined its use.
Initial reconstruction was performed by rearranging the breast parenchyma to correct volume loss. Glandular flaps were approximated using 3-0 Vicryl® sutures (Ethicon Inc., Somerville, NJ, USA).
When parenchymal rearrangement alone was anticipated to be insufficient to prevent contour deformity, a standardized volume (5 cc) of micronized ADM was used for volume replacement.
Paste-type micronized ADM products included Megafill® 5 cc (L&C BIO, Seoul, Korea) and CG Realloputty® 5 cc (CGBio Corp., Seongnam, Korea). After parenchymal repositioning, micronized ADM was injected into the residual cavity to fill dead space and was carefully covered with surrounding subcutaneous tissue to avoid direct contact with the undersurface of the skin. In the BCS-only group, reconstruction was performed using parenchymal repositioning without ADM. Subcuticular dermal sutures were placed using 3-0 Vicryl®, followed by skin closure with Maxon sutures (Covidien, Dublin, Ireland) (Figure 1). For invasive breast cancer, sentinel lymph node biopsy was performed through a separate axillary incision. A drain was placed in the axilla when sentinel lymph node biopsy was performed, while no drain was placed at the breast surgical site. Detailed descriptions of the surgical technique are provided in Appendix 1.
Red breast syndrome (RBS) was defined as localized erythema of the breast without associated clinical signs of infection, such as fever, pain, or elevated inflammatory markers. Patients presenting with erythema were evaluated clinically to differentiate RBS from postoperative infection (15). Postoperative surveillance followed the institutional breast cancer follow-up protocol, including regular clinical examination, annual mammography and ultrasonography. Patients were routinely followed at 6-month intervals after surgery. Postoperative photographs used for cosmetic assessment were obtained after completion of adjuvant radiotherapy, when breast contour had stabilized. In addition, breast MRI was performed approximately every 1–2 years as part of routine surveillance in many patients under the Korean national health insurance system, where imaging costs are substantially reduced for breast cancer patients.
Statistical analysis
To adjust for baseline differences between the BCS-only and ADM groups, IPTW based on propensity scores was performed. Propensity scores were estimated using a logistic regression model including clinically relevant covariates such as age, tumor stage, tumor type, tumor location, and resection volume.
After applying IPTW, balance between groups was assessed using standardized mean differences. Weighted analyses were then performed to compare operative and postoperative outcomes between the two groups. A two-sided P value of <0.05 was considered statistically significant. All statistical analyses were performed using SPSS software (IBM Corp., Armonk, NY, USA).
Results
All eligible patients during the study period were included, and no patients were excluded after eligibility confirmation. All included patients were followed for at least 1 month postoperatively for complication assessment. A total of 167 patients were included in this retrospective study, including 94 patients in the BCS-only group and 73 patients in the ADM group. Baseline clinicopathologic characteristics before and after IPTW adjustment are summarized in Table 1. Although baseline differences were observed between the groups, these differences were well balanced after IPTW adjustment. The mean patient age was 57.3 years (range, 21–84 years) in the BCS-only group and 51.8 years (range, 33–72 years) in the ADM group. The mean operative time was 83.0 minutes (range, 33–137 minutes) in the BCS-only group and 83.6 minutes (range, 42–145 minutes) in the ADM group. The mean resected breast volumes were 25.44±16.48 and 25.14±12.83 cm3, respectively, with no statistically significant difference between the two groups. Pathological T stage, N stage, histologic subtype, and tumor location did not differ significantly between the two groups. Postoperative complications within 1 month after surgery are summarized in Table 2 after IPTW adjustment. Postoperative complications were infrequent. Seroma occurred in three patients and hematoma occurred in one patient. The seroma that occurred in both groups were resolved with a single aspiration. In the BCS only group, a hematoma developed postoperatively, requiring an evacuation procedure. One patient in the ADM group developed wound dehiscence with associated postoperative infection and subsequently required ADM removal. No cases of RBS were observed. The patient only had redness on the skin around the operation site without accompanying symptoms such as fever or pain. Cosmetic outcomes were generally acceptable in both groups during early follow-up. Details of the subjective cosmetic outcome assessment are described in Appendix 2. To evaluate the esthetic outcomes, photographs of the breast were taken before and after surgery. Figure 2 shows preoperative and postoperative photographs of a case in which glandular tissue was mobilized and repositioned following BCS. The breast cancer was located in the upper inner quadrant of the breast. The patient in this case declined the use of ADM, necessitating oncoplastic surgery using only the patient’s own tissue. To minimize breast contour deformity during the tissue repositioning, the lower breast tissue was advanced to reposition the glandular tissue, which resulted in a postoperative depression in the inner lower quadrant.
Table 1
| Characteristics | IPTW | P value | |
|---|---|---|---|
| BCS only (n=94) | BCS with ADM (n=73) | ||
| Age, years | 54.74±12.23 | 53.19±9.16 | 0.35 |
| T stage | 0.84 | ||
| Tis | 17 (18.3) | 16 (21.8) | |
| T1 | 61 (65.1) | 45 (62.1) | |
| T2 | 16 (16.6) | 12 (16.1) | |
| N stage | 0.84 | ||
| N0 | 60 (63.8) | 49 (66.7) | |
| N1 | 15 (16.0) | 12 (16.3) | |
| N2 | 1 (0.6) | 0 (0.0) | |
| N3 | 1 (1.2) | 0 (0.0) | |
| Nx | 17 (17.6) | 12 (17.0) | |
| Histologic subtype | 0.93 | ||
| DCIS | 17 (18.2) | 16 (21.8) | |
| IDC | 70 (74.6) | 52 (71.2) | |
| ILC | 2 (1.8) | 1 (1.2) | |
| Others (mucinous, metaplastic) | 5 (5.4) | 4 (5.8) | |
| Histologic tumor size (cm) | 1.32±0.85 | 1.31±0.95 | 0.95 |
| Resected breast volume (cm3) | 25.44±16.48 | 25.14±12.83 | 0.89 |
| Location | >0.99 | ||
| Upper inner | 23 (24.6) | 19 (26.1) | |
| Upper outer | 43 (45.7) | 32 (44.3) | |
| Lower inner | 8 (8.7) | 6 (8.6) | |
| Lower outer | 13 (13.4) | 10 (13.9) | |
| Central | 7 (7.6) | 6 (8.1) | |
| Total operation time (minutes) | 83.00±26.38 | 83.58±22.92 | 0.87 |
Values are presented as mean ± standard deviation or number (%). Propensity scores were estimated using a logistic regression model including age, tumor stage, tumor type, tumor location, and resection volume. Weighted values represent IPTW-adjusted estimates to balance baseline characteristics between groups. Nx indicates nodal status not assessed/pathologic nodal status not available. ADM, acellular dermal matrix; BCS, breast-conserving surgery; DCIS, ductal carcinoma in situ; IDC, invasive ductal carcinoma; ILC, invasive lobular carcinoma; IPTW, inverse probability of treatment weighting; N, node; T, tumor.
Table 2
| Complications | IPTW | |
|---|---|---|
| BCS only (n=94) | BCS with ADM (n=73) | |
| Seroma | 3 (3.2) | 1 (1.4) |
| Red breast syndrome | 0 | 0 |
| Infection | 0 | 1 (1.4)† |
| Hematoma | 1 (1.1) | 0 |
| Total | 4 (4.3) | 2 (2.8) |
Values are presented as number (%). †, one patient required reoperation and ADM removal. Complications were assessed within 1 month after surgery. Weighted analyses were performed using IPTW-adjusted data. ADM, acellular dermal matrix; BCS, breast-conserving surgery; IPTW, inverse probability of treatment weighting.
Figure 3 presents preoperative and postoperative photographs of a case in which, after breast conserving surgery, glandular tissue was mobilized and repositioned, with paste-type ADM used to fill the resulting dead space. The breast cancer was located in the lower inner quadrant of the left breast. The surgical incision was approximately 3 cm around the areola. Postoperative assessment demonstrated preservation of breast contour without obvious deformity.
Discussion
ADM has been widely used in implant-based breast reconstruction, particularly in immediate tissue expander reconstruction following mastectomy (9-11). With the recent development of various ADM forms, its application has expanded to volume replacement in oncoplastic BCS. Among the available types, paste-type micronized ADM offers practical advantages due to its injectability and ability to conform to three-dimensional soft tissue defects (12-14). In this study, volume replacement using paste-type micronized ADM was technically simple and did not significantly prolong operative time compared with conventional oncoplastic BCS. Early postoperative complications were infrequent and manageable, with a low incidence of complications, including one case of wound dehiscence with associated infection requiring ADM removal, and no cases of RBS (15,16). These findings suggest that the use of micronized ADM is a feasible and safe adjunct for volume replacement in selected patients undergoing BCS.
Cosmetic outcomes appeared acceptable in both groups during early follow-up. Although cosmetic outcomes were not assessed using validated quantitative tools, representative cases demonstrated preservation of breast contour, suggesting a potential role of micronized ADM in selected cases where parenchymal rearrangement alone may be insufficient.
When introducing new reconstructive materials is their impact on postoperative imaging surveillance. Previous studies have reported that sheet-type or pellet-type ADM may mimic malignant lesions on follow-up imaging, potentially complicating cancer surveillance (17,18). In contrast, micronized ADM demonstrated relatively minimal radiologic changes in this study. On ultrasonography and magnetic resonance imaging, the ADM-inserted site showed imaging characteristics similar to those of surrounding normal tissue, with minimal or no contrast enhancement. These findings suggest that micronized ADM may have potential advantages in postoperative imaging follow-up compared with other ADM types (Figure 4). Additional details regarding postoperative imaging characteristics of micronized ADM are provided in Appendix 3. Despite these favorable early outcomes, this study has several limitations.
First, the retrospective design and single-institution setting introduce the possibility of selection bias, particularly due to surgeon-driven intraoperative decision-making regarding ADM use.
Second, cosmetic outcomes were evaluated subjectively without the use of validated patient-reported outcome measures. Third, the follow-up period was relatively short, precluding assessment of long-term cosmetic durability, oncologic outcomes, and ADM-related complications. Therefore, the results should be interpreted with caution.
These findings suggest that paste-type micronized ADM may be a useful adjunct for volume replacement in oncoplastic BCS, offering technical feasibility and acceptable early safety outcomes. Further prospective studies with standardized cosmetic assessments and longer follow-up are warranted to better define the role of micronized ADM in BCS.
Conclusions
ADM has been widely used in implant-based reconstruction following total mastectomy, whereas its direct use for structural volume replacement in BCS has been reported only in limited studies (12-14,18). In this study, oncoplastic BCS with volume replacement using paste-type micronized ADM demonstrated acceptable early safety outcomes.
The injectable nature of micronized ADM allows convenient intraoperative handling and may assist in volume replacement when parenchymal rearrangement alone is insufficient. In addition, the favorable postoperative imaging characteristics observed in this study may have potential implications for postoperative imaging evaluation.
Nevertheless, this study has several limitations, including its retrospective design, single-institution setting, relatively small sample size, and short follow-up period. As a result, definitive conclusions regarding long-term oncologic safety and cosmetic outcomes cannot be established. Further prospective studies with larger cohorts, standardized cosmetic assessment tools, and longer follow-up are warranted to clarify the role of micronized ADM in oncoplastic BCS.
Acknowledgments
The authors thank the clinical staff of Dong-A University Hospital for their assistance with patient care and data collection. This study was previously presented in part as a poster at the European Breast Cancer Conference (EBCC) in 2023.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0002/rc
Data Sharing Statement: Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0002/dss
Peer Review File: Available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0002/prf
Funding: This study was supported by a research grant from
Conflicts of Interest: Both authors have completed the ICMJE uniform disclosure form (available at https://gs.amegroups.com/article/view/10.21037/gs-2026-1-0002/coif). Both authors report that this study was supported by a research grant from Dong-A University College of Medicine. The authors have other no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Institutional Review Board of Dong-A University Hospital (IRB No. DAUHIRB-23-219), and the requirement for informed consent was waived due to the retrospective nature of the study.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
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