Oncoplastic versus standard breast-conserving surgery for extensive ductal carcinoma in situ: a retrospective cohort study of lesions 4 cm or larger treated 1995–2018

Introduction

Ductal carcinoma in situ (DCIS) diagnosis increased dramatically as population screening was introduced in the 1980s and 1990s (1-3). Although the rate of increase has stabilised in recent years, DCIS continues to constitute a substantial proportion of screen-detected disease across all age groups (4,5).

Surgical management of DCIS remains challenging, particularly in cases with extensive radiological or pathological spread. Mastectomy is undertaken in a higher proportion of women with screen-detected DCIS, than screen-detected invasive breast cancer, most commonly in the presence of large lesion size, multifocality, or high-grade disease (6) When breast-conserving surgery (BCS) is performed, re-operation due to involved margins is common, and more common than after BCS for invasive disease. Larger DCIS size is a consistent predictor of margin positivity and the need for further surgery, a relationship that has also been demonstrated in long-term series (6). Earlier guidance from the Quality Assurance Guidelines for Surgeons in Breast Cancer Screening recommended mastectomy for patients with extensive DCIS greater than 4 cm in diameter (7). While contemporary practice shows a gradual expansion of eligibility for BCS, the technical complexity of resecting large-volume DCIS while maintaining acceptable cosmetic outcomes persists (8,9).

Standard BCS (S-BCS) aims to achieve oncological clearance while preserving breast tissue, although aesthetic outcomes may be compromised when the excision volume is large relative to breast size. Oncoplastic BCS (O-BCS) combines wide local excision with volume displacement or volume replacement techniques to optimise cosmetic outcomes without compromising oncological safety (8,9). These approaches facilitate breast preservation in patients who might otherwise require mastectomy, often by allowing large percentage resections and wide margins of excision whilst maintaining cosmetic outcomes. However, evidence comparing outcomes between S-BCS and O-BCS specifically in large-volume DCIS remains limited, and the existing literature is characterised by significant methodological heterogeneity. The majority of published series examining oncoplastic techniques in DCIS are either single-arm studies reporting outcomes after O-BCS without a comparator group, or comparative studies in which the oncoplastic approach is benchmarked against mastectomy rather than standard BCS (10,11). This is a critical limitation, as the clinically relevant question for patients who wish to pursue breast conservation is not whether O-BCS is preferable to mastectomy, but whether it outperforms conventional excision in achieving safe margins while preserving the breast. Where direct comparisons between O-BCS and standard BCS have been reported, they have generally included heterogeneous cohorts with mixed lesion sizes and have not restricted analysis to large-volume disease specifically (12). Studies focused on DCIS as a pure population have tended to evaluate oncological safety without a direct surgical comparator (13), limiting conclusions about the relative merits of different breast-conserving approaches (11). Across these studies, a consistent signal emerges that oncoplastic techniques are associated with lower positive-margin rates and reduced conversion to mastectomy, but the evidence base is further constrained by short follow-up periods and the absence of multivariable adjustment for differences in patient and tumour characteristics between surgical groups (10-13). Evidence specifically addressing the surgical and oncological outcomes of O-BCS versus S-BCS in patients with DCIS measuring 4 cm or greater, with adequate follow-up and appropriate statistical adjustment, is therefore lacking.

This study is a retrospective analysis of patients with DCIS greater than 4 cm treated at the Nottingham Breast Institute (NBI) between 1995 and 2018. It compares oncological and surgical outcomes following O-BCS and S-BCS, assessing tumour characteristics, margin status, re-excision rates, local recurrence, and survival. The aim is to determine whether oncoplastic techniques provide safe and effective alternatives to mastectomy for patients with extensive DCIS. We present this article in accordance with the STROBE reporting checklist (available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-73/rc) (14).

Methods

An anonymised database of all DCIS patients in the NBI was generated by linking records from the NBI Clinical Database and the Nottingham University Hospitals NHS Trust Histopathology Database. The cohort included all patients who underwent BCS for DCIS measuring 4 cm or larger between 1995 and 2018. The patient selection process is summarised in Figure 1. Clinical records were reviewed to verify surgical, pathological and follow-up information. Follow-up was updated in January 2024. However, survival data were incomplete for a proportion of patients, particularly in earlier S-BCS cases and more recent O-BCS cases and survival analyses were therefore performed on available cases only. All histopathological specimens were reported by specialist breast histopathologists within the Department of Histopathology at Nottingham University Hospitals NHS Trust. This was a convenience sample comprising all eligible patients treated at our institution during the study period; no a priori sample size calculation was performed.

Figure 1 Patient flow diagram showing eligibility, surgical allocation, and outcome pathways for patients with DCIS measuring 4 cm or greater treated at the Nottingham Breast Institute 1995–2018. BCS, breast-conserving surgery; DCIS, ductal carcinoma in situ; O-BCS, oncoplastic breast-conserving surgery; OS, overall survival; RFS, recurrence-free survival; S-BCS, standard breast-conserving surgery.

Surgical technique definitions

S-BCS was defined as a segmental excision or wide local excision without formal oncoplastic reshaping. O-BCS included both volume displacement procedures, specifically therapeutic mammaplasty, reduction mammoplasty and wedge mammoplasty, and volume replacement techniques, specifically lateral intercostal artery perforator (LICAP) flap, lateral thoracic artery perforator (LTAP) flap, chest wall perforator flaps and latissimus dorsi (LD) flap. All O-BCS procedures were performed by surgeons with oncoplastic training (either plastics or breast surgery background).

Outcome definitions

The primary surgical outcome was BCS success, defined as achievement of tumour-free margins without subsequent completion mastectomy within the initial treatment episode. Where specimens contained areas of more than one DCIS grade, the case was classified according to the highest grade component. Tumour localisation was predominantly wire-guided, with a small number of cases using radioisotope occult lesion localisation (ROLL). According to the final histopathology report, margin status was classified as negative if tumour was ≥1 mm from the nearest inked resection margin, close if tumour was <1 mm from but not at the inked resection margin, and positive if tumour was present at the inked resection margin. The minimum margin considered clinically adequate for DCIS evolved over the study period in line with changing institutional and national guidance: prior to 2008, a minimum clearance of 10 mm was required; from 2008 to 2016, this threshold was 5 mm; and from 2016 onwards, 2 mm. Re-excision and conversion-to-mastectomy decisions were made against the era-appropriate threshold in each case. Re-excision was defined as return to theatre for further margin clearance after the initial operation. Conversion to mastectomy was defined as mastectomy performed after failed breast conservation within the same treatment pathway. Local recurrence was defined as ipsilateral DCIS or invasive breast cancer occurring after completion of initial treatment. Recurrence-free survival (RFS) was defined as the interval from the date of primary surgery to the first occurrence of local recurrence, distant recurrence or death from any cause. Overall survival (OS) was measured from the date of surgery to death from any cause.

Statistical analysis

Descriptive statistics summarised demographic, tumour and treatment characteristics. Categorical variables were expressed as frequencies and percentages and compared using Fisher’s exact test. Continuous variables were summarised as means or medians and compared using independent samples t-tests. BCS success, re-excision and conversion rates were compared between groups using Fisher’s exact test. RFS and OS were estimated using Kaplan-Meier methods, with differences assessed using the log-rank test. Patients without events were censored at the date of last follow-up. Two multivariable logistic regression models were fitted. The first modelled BCS success as the outcome with surgical group, age, and tumour size as covariates. The second modelled local recurrence as the outcome with surgical group, age, and radiotherapy status as covariates. P values <0.05 were considered significant. Analyses were conducted using R statistical software. All analyses were conducted using a complete-case approach. Missing survival data were retained in descriptive summaries but omitted from survival modelling.

Subgroup analysis

A predefined subgroup analysis was conducted for patients with DCIS lesions greater than 50 mm in maximum pathological extent. This subgroup was selected to evaluate surgical performance and oncological outcomes in cases where breast conservation is traditionally challenging. Comparative analyses between S-BCS and O-BCS within this subgroup included BCS success, margin status, re-excision, conversion to mastectomy, local recurrence and RFS. Statistical comparisons were performed using Fisher’s exact test for categorical variables and independent samples t-tests for continuous variables, with survival differences assessed using log-rank tests.

Ethical consideration

The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Research Ethics Committee of Nottingham University Hospitals NHS Trust Research and Innovation Department (Oncoplastic audit ID 15-911C, date: 22/03/2016) and individual consent for this retrospective analysis was waived.

Results

Baseline characteristics

A total of 139 patients with DCIS 4 cm and over who underwent initial BCS at the NBI between 1995 and 2018 were included in the study. The median age at diagnosis was 55 years (range, 36–83 years). Of these, 94 patients (67.6%) underwent S-BCS and 45 patients (32.4%) underwent O-BCS. The mean duration of follow-up was 6 years. Clinicopathological characteristics of the cohort are presented in Table 1.

Patients in the O-BCS group were significantly older on average than those in the S-BCS group (mean 58.9 vs. 55.1 years; P=0.04). Tumour size categories were similar across groups, with mean tumour size of 61.1 mm for S-BCS and 63.7 mm for O-BCS (P=0.50). DCIS grade, classified according to the highest grade component, was predominantly high grade in both groups (S-BCS 52.1%, O-BCS 64.4%) with no significant difference between groups (P=0.07). Margin status varied significantly between groups (P<0.001), the S-BCS group had a significantly higher rate of positive margins compared to the O-BCS group (76.6% vs. 26.7%, P<0.001).

Figure 2 shows the number of S-BCS and O-BCS procedures performed each year. The use of S-BCS procedures declined across the study period, whereas O-BCS procedures increased in later years (mean year of surgery: S-BCS 2006, O-BCS 2014), reflecting growing adoption of oncoplastic techniques within the unit.

Figure 2 Annual number of S-BCS and O-BCS procedures for DCIS measuring 4 cm or greater at the Nottingham Breast Institute from 1995 to 2018. The figure demonstrates increasing adoption of oncoplastic techniques over time. DCIS, ductal carcinoma in situ; O-BCS, oncoplastic breast-conserving surgery; S-BCS, standard breast-conserving surgery.

Surgical outcomes

The O-BCS cohort demonstrated significantly superior surgical outcomes across all measures. Breast conservation was successfully achieved in 37 of 45 O-BCS patients (82.2%) compared with 26 of 94 S-BCS patients (27.7%) [odds ratio (OR) 11.84, 95% confidence interval (CI): 4.67–33.51, P<0.001]. Conversion to mastectomy was significantly higher in the S-BCS group, occurring in 68 patients (72.3%) compared with 8 (17.8%) in the O-BCS group (P<0.001). These outcomes are summarised in Figure 3A. Among patients who achieved breast conservation (S-BCS n=26, O-BCS n=37), re-excision to clear margins was required significantly more often in the S-BCS group [17 of 26 patients (65.4%) vs. 3 of 37 O-BCS patients (8.1%), P<0.001]. Of these, adjuvant radiotherapy was received by 12 of 26 S-BCS patients (46.2%) and 34 of 37 breast-conserved O-BCS patients (91.9%) (P<0.001). No patient in either group received a radiotherapy boost. Three O-BCS patients did not receive radiotherapy: one declined and one was managed without radiotherapy following a clinical decision in the context of low-grade DCIS with margins exceeding 10 mm. Re-excision and adjuvant radiotherapy rates among breast-conserved patients are shown in Figure 3B.

Figure 3 Comparison of BCS success, re-excision, and conversion to mastectomy between S-BCS and O-BCS for DCIS measuring 4 cm or greater. (A) BCS success and conversion to mastectomy rates in the full cohort (S-BCS n=94, O-BCS n=45). (B) Re-excision to clear margins and adjuvant radiotherapy rates among patients who achieved breast conservation (S-BCS n=26, O-BCS n=37). Bars represent percentages within each surgical group; absolute numbers are shown above each bar. BCS, breast-conserving surgery; DCIS, ductal carcinoma in situ; O-BCS, oncoplastic breast-conserving surgery; S-BCS, standard breast-conserving surgery.

To assess whether the higher rate of breast conservation in the O-BCS group was independent of potential confounders, a multivariable logistic regression model was fitted with BCS success as the outcome and surgical group, age, and tumour size as covariates. O-BCS remained a strong and independent predictor of successful breast conservation after adjustment (OR 12.40, 95% CI: 5.18–33.19, P<0.001). Neither age (OR 1.02, 95% CI: 0.98–1.06, P=0.30) nor tumour size (OR 0.99, 95% CI: 0.97–1.01, P=0.21) reached statistical significance, suggesting that the surgical advantage of O-BCS is not explained by differences in these variables between groups.

Local recurrence

Local recurrence occurred in 9 of 94 S-BCS patients (9.6%) and 1 of 45 O-BCS patients (2.2%). This difference did not reach statistical significance (P=0.17), and the study was underpowered to detect a difference in recurrence rates given the small number of events (n=10 total). Of the nine recurrences in the S-BCS group, seven were invasive and two were DCIS. The single recurrence in the O-BCS group was invasive. Among patients who achieved breast conservation, radiotherapy status was significantly associated with recurrence. Recurrence occurred in 8 of 17 patients (47.1%) who did not receive radiotherapy compared with 2 of 46 (4.3%) who did (P<0.001). Within the S-BCS group, recurrence occurred in 7 of 14 patients (50.0%) who did not receive radiotherapy and 2 of 12 (16.7%) who did. No recurrence was observed among the 34 O-BCS patients who received radiotherapy. The recurrence rate among the 3 O-BCS patients who did not receive radiotherapy was 1 of 3 (33.3%), though this subgroup is too small to draw meaningful conclusions.

A multivariable logistic regression model including surgical group, age, and radiotherapy status did not identify any significant independent predictor of local recurrence: O-BCS group (OR 0.24, 95% CI: 0.01–1.94, P=0.25), age (OR 0.94, 95% CI: 0.87–1.01, P=0.13), and radiotherapy (OR 1.12, 95% CI: 0.13–6.03, P=0.91). This model should be interpreted with caution given that only 10 recurrence events were available, rendering it severely underpowered for multivariable analysis.

RFS

RFS data were available for all 94 S-BCS patients and 26 of 45 O-BCS patients, with RFS data unavailable for 19 O-BCS patients, predominantly those treated in more recent years with insufficient follow-up duration. RFS was comparable between groups, with no statistically significant difference on log-rank analysis (Chi-squared 0.006, P=0.94). Median RFS was not reached in either group. Kaplan-Meier curves are shown in Figure 4.

Figure 4 Recurrence-free survival following S-BCS and O-BCS for DCIS measuring 4 cm or greater. Survival estimates generated using the Kaplan-Meier method. P value derived from the log-rank test. DCIS, ductal carcinoma in situ; O-BCS, oncoplastic breast-conserving surgery; S-BCS, standard breast-conserving surgery.

OS

OS data were available for 25 of 94 S-BCS patients and 42 of 45 O-BCS patients. The 69 S-BCS patients with missing survival data were treated significantly earlier (mean year 2002.9 vs. 2011.3), reflecting incomplete data capture in the earlier phase of the study period. Given this imbalance, OS findings should be interpreted with caution and are included for descriptive purposes only. No significant difference in OS was detected between groups (χ²=0.023, P=0.88), and median OS was not reached in either group. Kaplan-Meier curves are shown in Figure 5.

Figure 5 Overall survival following S-BCS and O-BCS for DCIS ≥4 cm with numbers at risk. DCIS, ductal carcinoma in situ; O-BCS, oncoplastic breast-conserving surgery; S-BCS, standard breast-conserving surgery.

O-BCS subgroup analysis

Among the 45 patients who underwent O-BCS, volume displacement by therapeutic mammoplasty was the predominant technique (n=36, 80.0%). Volume replacement was performed in 9 patients (20.0%) using chest wall perforator flaps (n=8; LICAP n=3, LTAP n=3, not further specified n=2) and LD flap (n=1). Given the small numbers in individual technique subgroups, no statistical comparisons of outcomes between techniques were undertaken.

Comparative outcomes for DCIS lesions larger than 5 cm

A total of 73 patients had DCIS lesions greater than 5 cm, comprising 46 from the S-BCS cohort and 27 from the O-BCS cohort. Breast conservation was successfully achieved in 23 of 27 O-BCS patients (85.2%) compared with 7 of 46 S-BCS patients (15.2%), representing a significantly higher rate of breast conservation in the O-BCS group (OR 29.74, 95% CI: 7.38–157.47, P<0.001). Conversion to mastectomy occurred in 39 of 46 S-BCS patients (84.8%) compared with 4 of 27 O-BCS patients (14.8%) (OR 0.03, 95% CI: 0.01–0.14, P<0.001).

Positive margins were significantly more frequent in the S-BCS group, occurring in 38 of 46 patients (82.6%) compared with 8 of 27 O-BCS patients (29.6%) (OR 0.09, 95% CI: 0.02–0.31, P<0.001). Among patients who achieved breast conservation in this subgroup (S-BCS n=7, O-BCS n=23), re-excision to clear margins was required in 5 of 7 S-BCS patients (71.4%) compared with 2 of 23 O-BCS patients (8.7%) (OR 0.05, 95% CI: 0.00–0.48, P=0.003).

Local recurrence within this subgroup was infrequent and did not differ significantly between groups, occurring in 3 of 46 S-BCS patients (6.5%) and 1 of 27 O-BCS patients (3.7%) (OR 0.56, 95% CI: 0.01–7.34, P>0.99). These findings are consistent with the overall cohort results, suggesting that the surgical advantages of O-BCS are maintained even for particularly extensive DCIS lesions.

Discussion

Key findings

In this cohort of patients with DCIS measuring 4 cm or greater, O-BCS achieved substantially higher BCS success than S-BCS. O-BCS resulted in significantly fewer positive margins, a markedly lower conversion-to-mastectomy rate, and no observed increase in local recurrence or survival disadvantage. Although recurrence appeared numerically lower in the O-BCS cohort, the study was not powered to detect a statistically significant difference because of the small number of events. These results were consistent in the subgroup of patients with lesions larger than 5 cm, indicating that oncoplastic techniques maintain their advantage even in very large-volume disease.

The marked difference in margin status is clinically important. Standard BCS was associated with substantially higher positive-margin rates, whereas O-BCS achieved negative margins more reliably, consistent with findings reported in large UK and European oncoplastic series (8,9,15).

Strengths and limitations

A major strength of this study is the relatively long follow-up period, with a mean duration of 6.2 years, which allows reliable assessment of recurrence and survival outcomes beyond the immediate post-operative period. Nevertheless, longer follow-up of 10 to 15 years would provide a more robust basis for interpretation, particularly given evidence that the cumulative recurrence rate for DCIS at 15 years is approximately twice that reported at 5 years (16). The dataset originates from a high-volume specialist breast unit with consistent surgical documentation, supporting internal validity. Detailed operative and margin data enabled clear comparison between standard and oncoplastic techniques.

However, several limitations must be acknowledged. This is a retrospective non-randomised study and the choice between S-BCS and O-BCS was surgeon-led, likely influenced by anatomical factors, DCIS location, degree of ptosis, anticipated cosmesis, patient acceptance of alterations in breast shape and size, and the evolving availability of oncoplastic expertise within the unit. As shown in Figure 2, O-BCS was increasingly adopted in later years, during which parallel improvements in imaging, localisation methods, margin assessment, and adjuvant treatment pathways may have independently influenced margin status, re-excision rates, and recurrence risk. S-BCS cases are overrepresented in the earlier years of the study, and these temporal changes may therefore confound the observed association between O-BCS and improved surgical outcomes.

Adjuvant radiotherapy is well established as a key determinant of local recurrence risk following BCS for DCIS. Randomised trial data demonstrate that radiotherapy approximately halves the risk of ipsilateral recurrence following breast conservation, with benefit maintained at 15-year follow-up regardless of grade, age, or margin status (17,18). Radiotherapy rates differed substantially between groups in this study, with 91.9% of breast-conserved O-BCS patients receiving adjuvant radiotherapy compared with 46.2% of breast-conserved S-BCS patients. No patient in either group received a boost, consistent with standard practice for DCIS at our institution during the study period. The difference in radiotherapy rates is itself a consequence of the higher mastectomy conversion rate in the S-BCS group, but it nonetheless represents a significant confounder for recurrence outcomes and limits direct comparison of recurrence rates between groups.

Recurrence analysis is based on a small number of events (n=10), and the study is underpowered to detect differences in recurrence between groups. The findings regarding recurrence should therefore be regarded as descriptive and hypothesis-generating rather than definitive. Incomplete survival data, particularly in the S-BCS group, reduced the number of patients evaluable for OS analysis. The small number of chest wall perforator flap procedures limits any comparison between O-BCS subtypes. As a single-centre study, generalisability may be limited, although the findings align with contemporary practice across multiple breast units.

Comparison with similar research

Our findings are consistent with existing evidence that oncoplastic approaches enable wider excisions without compromising oncological outcomes, and that O-BCS reduces positive-margin rates and decreases the need for completion mastectomy in large or unfavourably positioned lesions (8,9,19). Published comparative series have tended to benchmark oncoplastic surgery against mastectomy rather than standard BCS, which addresses the question of oncological safety but leaves the relative surgical performance of the two breast-conserving approaches poorly characterised (10). Where O-BCS has been compared directly with standard BCS, studies have generally included heterogeneous cohorts across a broad range of lesion sizes, limiting the applicability of their findings to the large-volume DCIS population specifically (13). Single-arm series reporting outcomes after O-BCS for large DCIS without a comparator group provide useful safety data but cannot quantify the surgical advantage over conventional excision (11). Studies focused exclusively on DCIS as a population have similarly been constrained by the absence of a direct surgical comparator and by follow-up periods insufficient to characterise long-term recurrence risk (10). The present study addresses these gaps by providing a direct comparison between S-BCS and O-BCS in a cohort restricted exclusively to DCIS ≥4 cm, with long-term follow-up and multivariable adjustment for key confounders. Regarding oncological outcomes, recurrence in this cohort was low in both groups, and the absence of a statistically significant difference between groups is consistent with the broader literature, which generally demonstrates that when negative margins are obtained, O-BCS does not increase the risk of local recurrence (13,20). The numerically lower recurrence rate observed in the O-BCS group is consistent with findings from other oncoplastic series and likely reflects the wider excision volumes achievable with oncoplastic techniques, though few studies reach statistical significance for this outcome given the low absolute event rates and long latency periods characteristic of DCIS recurrence (20).

Explanations of findings

The improved margin status and higher breast-conserving success observed with O-BCS are likely due to oncoplastic approaches enabling wider resections while preserving breast contour, facilitating complete excision even in large-volume or anatomically challenging DCIS.

The higher positive-margin rate in the S-BCS cohort probably reflects the constraints of standard excision and the intolerance of such surgery to achieve clear margins if the pathological size of DCIS exceeds the radiological size, which is common.

The lower absolute number of recurrences in the O-BCS cohort is consistent with wider excision, although this difference should be interpreted cautiously given the small number of events. Prior studies also highlight the difficulty of detecting recurrence differences in DCIS due to low event rates and long latency (20,21).

Implications and actions needed

These findings support the routine consideration of oncoplastic techniques for patients with large-volume DCIS who wish to pursue breast conservation. Wider availability of oncoplastic expertise may reduce unnecessary mastectomies and improve both oncological and aesthetic outcomes.

The significantly lower positive-margin rate associated with O-BCS reinforces the importance of offering these techniques for large or complex lesions. Margin status is a key determinant of re-excision and conversion to mastectomy, and improving initial margin clearance has meaningful implications for surgical efficiency, patient experience, and treatment burden.

Although recurrence appeared numerically lower following O-BCS, larger multicentre datasets are needed to explore whether differences in recurrence are clinically meaningful to a wider population. Prospective studies incorporating patient-reported aesthetic and quality-of-life outcomes are essential to evaluate the broader impact of oncoplastic surgery. Expanding training and oncoplastic capacity within breast units may be necessary to ensure equitable access to these procedures.

Conclusions

O-BCS demonstrated clear advantages over S-BCS for patients with DCIS measuring 4 cm or greater. O-BCS achieved significantly higher negative-margin rates and a markedly lower conversion-to-mastectomy rate, indicating that volume displacement and replacement techniques can improve operative success in large-volume disease. Local recurrence and survival outcomes did not differ significantly; however, the number of events was small, and these analyses are descriptive only. Overall, these findings suggest that oncoplastic techniques may expand the feasibility of breast conservation in selected patients with extensive DCIS. Larger prospective studies incorporating long-term follow-up and patient-reported outcomes are needed to determine oncological outcomes more reliably and fully to better evaluate aesthetic benefit.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-73/rc

Data Sharing Statement: Available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-73/dss

Peer Review File: Available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-73/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://abs.amegroups.com/article/view/10.21037/abs-2025-1-73/coif). E.W. serves as an unpaid editorial board member of Annals of Breast Surgery from September 2025 to December 2027. The other authors have 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. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Research Ethics Committee of Nottingham University Hospitals NHS Trust Research and Innovation Department (Oncoplastic audit ID 15-911C, date: 22/03/2016) and individual consent for this retrospective analysis was waived.

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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