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. 2020 Aug 6;107(13):1762–1772. doi: 10.1002/bjs.11838

Rates of re‐excision and conversion to mastectomy after breast‐conserving surgery with or without oncoplastic surgery: a nationwide population‐based study

E Heeg 1,2,✉, M B Jensen 4, L R Hölmich 6, A Bodilsen 7, R A E M Tollenaar 2, A V Lænkholm 10, B V Offersen 8, B Ejlertsen 4,5, M A M Mureau 3, P M Christiansen 9
PMCID: PMC7689836  PMID: 32761931

Abstract

Background

There is no consensus regarding the impact of oncoplastic surgery (OPS) on rates of re‐excision and conversion to mastectomy following breast‐conserving surgery (BCS). Here these two outcomes after BCS and OPS were compared in a nationwide population‐based setting.

Methods

In Denmark, all OPS is registered and categorized into volume displacement, volume reduction or volume replacement. Patients who underwent BCS or OPS between 2012 and 2018 were selected from the Danish Breast Cancer Group database. Multivariable analyses were performed to adjust for confounders, and propensity score matching to limit potential confounding by indication bias.

Results

A total of 13 185 patients (72·5 per cent) underwent BCS and 5003 (27·5 per cent) OPS. Volume displacement was used in 4171 patients (83·4 per cent), volume reduction in 679 (13·6 per cent) and volume replacement in 153 (3·1 per cent). Re‐excision rates were 15·6 and 14·1 per cent after BCS and OPS respectively. After adjusting for confounders, patients were less likely to have a re‐excision following OPS than BCS (odds ratio (OR) 0·80, 95 per cent c.i. 0·72 to 0·88), specifically after volume displacement and reduction. The rate of conversion to mastectomy was similar after OPS and BCS (3·2 versus 3·7 per cent; P = 0·105), but with a lower risk in adjusted analysis (OR 0·69, 0·58 to 0·84), specifically after volume displacement and reduction procedures. Findings were similar after propensity score matching.

Conclusion

A modest decrease in re‐excision rate and less frequent conversion to mastectomy were observed after OPS compared with BCS.

Compared with breast‐conserving surgery, oncoplastic surgery results in a modest decrease in re‐excision rates and less frequent conversion to mastectomy.

graphic file with name BJS-107-1762-g001.jpg

Rates similar to breast‐conserving surgery only

Introduction

Randomized trials 1 , 2 , 3 , 4 , 5 conducted in the 1980s established breast‐conserving surgery (BCS) followed by radiotherapy as the preferred treatment for early‐stage breast cancer. Improved breast cancer survival rates 6 , 7 have led to an increased focus on cosmetic outcomes after treatment 8 . Consequently, a challenging balance has emerged between achieving complete resection of the tumour with appropriate tumour‐free margins and a favourable cosmetic result. Not every patient is eligible for BCS owing to anatomical and tumour characteristics 9 .

Oncoplastic surgery (OPS) improves cosmetic outcomes and is nowadays used in up to 34 per cent of patients with breast cancer undergoing BCS 10 , 11 , 12 , 13 , 14 . Previous studies 15 , 16 have demonstrated that by using OPS breast conservation becomes an alternative to mastectomy in patients with large and multifocal tumours. Compared with BCS, OPS is associated with larger resections 17 , 18 , and good long‐term survival outcomes 11 , 13 , 18 , 19 and quality of life 20 , 21 , 22 . Achieving larger tumour resections with OPS may also reduce the number of re‐excisions owing to insufficient margins. High‐quality evidence regarding the impact of OPS on re‐excisions is, however, sparse 18 , 19 .

Between 2000 and 2009, re‐excision after BCS occurred in about 17 per cent of patients with breast cancer in Denmark 23 , which is within the reported range of 5–35 per cent 22 , 24 , 25 , 26 . Re‐excision requiring mastectomy is commonly defined as conversion to mastectomy. Re‐excision and conversion to mastectomy are associated with more morbidity, complications, poorer aesthetic outcome, greater patient distress and increased healthcare costs 27 , 28 . Furthermore, for patients in whom free margins were not achieved during primary BCS, an increased risk of ipsilateral breast tumour recurrence has been reported 23 .

In Denmark, OPS techniques have been registered prospectively by the Danish Breast Cancer Group (DBCG) for all patients undergoing BCS since July 2010. The primary goal of the present study was to compare re‐excision rates after BCS versus OPS in patients with early‐stage breast cancer, in a population‐based national setting. A further aim was to investigate whether OPS results in a lower conversion to mastectomy rate (CMR) than BCS. As several studies 11 , 12 , 13 , 29 have shown that patients may not have the same likelihood of receiving OPS based on their baseline characteristics, additional propensity score matching was used to limit the potential confounding by indication bias.

Methods

Since 1978, the DBCG has collected clinicopathological and treatment characteristics and follow‐up data prospectively from all patients diagnosed with a primary invasive breast cancer 30 . OPS is categorized into three types: volume displacement, defined as local rearrangement of tissue near the lumpectomy cavity in order to close the defect; volume reduction, defined as the use of a breast reduction technique to remove tumour and improve breast shape at the same time; and volume replacement, defined as tissue transfer from outside the breast into the breast (such as local perforator flaps). A more detailed description of data collection by the DBCG has been published 30 , 31 . The study was approved by the Scientific Committee of Surgery within the DBCG and the Danish Clinical Registries.

Study population

All women with invasive breast cancer without distant metastasis, who underwent primary BCS between January 2012 and December 2018, identified from the DBCG database were included. Patients who received neoadjuvant therapy or surgical biopsy as the only surgical procedure were excluded. Patients were categorized into four groups: BCS (without OPS), OPS with volume displacement, OPS with volume reduction, and OPS with volume replacement.

Outcomes

The primary outcome was re‐excision, defined as a second BCS procedure or mastectomy following the primary BCS within 2 months of the initial operation. This interval was chosen to limit potential re‐excisions owing to breast cancer recurrence. Information about re‐excision, including type, was retrieved from Danish National Patient Registry 32 . Re‐excision rates among patients aged over 50 years might be influenced by use of boost radiation for treatment of insufficient margins, so secondary interventions (re‐excision or boost radiation) were compared in patients aged 50 years or older undergoing BCS or OPS. The secondary outcome, CMR, was defined as the rate of mastectomy following the primary BCS within 2 months of the initial operation.

Confounders

Co‐morbidity was classified according to the Charlson Co‐morbidity Index (CCI) 33 . Histological subtypes, such as papillary, medullary and mucinous subtypes, were categorized as ‘other’. In Denmark, grading is applied to invasive ductal and lobular carcinomas, but not to subtypes classified as ‘other’, according to the modified version of the Bloom Richardson scoring system of Elston and Ellis 34 . Breast cancer was classified as oestrogen receptor‐positive when at least 10 per cent of cells stained positive in immunohistochemical analyses. Expression of human epidermal growth factor receptor 2 (HER2) was determined according to standard recommendations 35 . Tumour size and lymph node status were categorized according to the seventh edition of the AJCC cancer staging classification 36 . Any missing characteristics were classified as unknown.

Guidelines

In accordance with Danish guidelines 30 , 31 , re‐excision was advised if invasive carcinoma was identified at the inked margins or ductal carcinoma in situ (DCIS) within 2 mm from the margin. Danish guidelines also recommend boost radiation in all patients younger than 50 years after BCS with or without OPS; and in those with a microscopic free margin of less than 2 mm for invasive breast cancer or DCIS, irrespective of age 37 , 38 .

Statistical analysis

Patient and tumour characteristics were compared between BCS and OPS groups using χ2 test for categorical variables, and Mann–Whitney U test or Kruskal–Wallis test for continuous variables. Unknown characteristics were included in the descriptive statistics. Two‐sided P < 0·050 was considered statistically significant. To adjust for confounders, a multivariable logistic regression model was used to estimate whether patients who underwent OPS were more likely to have a re‐excision than those who had BCS. Results were expressed as odds ratios (ORs) with 95 per cent confidence intervals, and the Wald test was used for analysis of statistical significance. The latter analyses were repeated for the secondary outcome CMR. Patients with unknown variables were included as a separate category in all analyses.

To evaluate whether associations were subject to confounding by indication, meaning that not all patients were equally likely to have received OPS, analyses were repeated in propensity score‐matched cohorts. Patients who underwent BCS were matched with those who had OPS as a whole and by each type of OPS. Patients were matched on the likelihood of undergoing OPS using the following co‐variables: year of operation, age, CCI score, histological finding, differentiation grade, oestrogen receptor positivity, HER2 status, T and N status 39 , 40 . Patients who underwent BCS were matched 1 : 1 with those who had OPS using a caliper width of 0.2 times the standard deviation of the logit of the propensity score 41 . Potential imbalances in characteristics before and after matching were shown using a standardized difference; a value of 10 per cent or more was indicative of an imbalance in characteristics 42 . All analyses were performed using SPSS® version 24 (IBM, Armonk, New York, USA).

Results

A total of 18 188 patients met the inclusion criteria, of whom 13 185 (72·5 per cent) underwent BCS and 5003 (27·5 per cent) OPS. Patients who had BCS were older than those who had OPS (mean(s.d.) 62·1(11·5) versus 59·9(11·5) years; P < 0·001) (Table  1 ). Patients who underwent OPS had a lower co‐morbidity score than those who had BCS (P < 0·001), but poorer prognostic tumour factors, including higher differentiation grade (P < 0·001), larger tumour size (P < 0·001) and more lymph node involvement (P < 0·001). The use of OPS decreased significantly from 30·3 per cent in 2012 to 26·4 per cent in 2018 (P < 0·001).

Table 1.

Baseline characteristics of patients who underwent breast‐conserving surgery or oncoplastic surgery

All patients (n = 18 188) BCS (n = 13 185) OPS (n = 5003) P †
Year of operation < 0·001
2012 2667 (14·7) 1858 (14·1) 809 (16·2)
2013 2733 (15·0) 2052 (15·6) 681 (13·6)
2014 2751 (15·1) 1933 (14·7) 818 (16·4)
2015 2626 (14·4) 1909 (14·5) 717 (14·3)
2016 2533 (13·9) 1852 (14·0) 681 (13·6)
2017 2476 (13·6) 1813 (13·8) 663 (13·3)
2018 2402 (13·2) 1768 (13·4) 634 (12·7)
Age (years) * 61·5(11·5) 62·1(11·5) 59·9(11·5)  < 0·001‡
Charlson Co‐morbidity Index score < 0·001
0 13 987 (76·9) 9942 (75·4) 4045 (80·9)
1 2500 (13·7) 1910 (14·5) 590 (11·8)
2 1118 (6·1) 868 (6·6) 250 (5·0)
≥ 3 583 (3·2) 465 (3·5) 118 (2·4)
Histological finding < 0·001
Ductal 14 777 (81·2) 10 669 (80·9) 4108 (82·1)
Lobular 1888 (10·4) 1339 (10·2) 549 (11·0)
Other 1505 (8·3) 1161 (8·8) 344 (6·9)
Unknown 18 (0·1) 16 (0·1) 2 (0·0)
Differentiation grade < 0·001
I 4809 (26·4) 3683 (27·9) 1126 (22·5)
II 7958 (43·8) 5700 (43·2) 2258 (45·1)
III 3747 (20·6) 2496 (18·9) 1251 (25.0)
Not determined 1505 (8·3) 1161 (8·8) 344 (6·9)
Unknown 169 (0·9) 145 (1·1) 24 (0·5)
Oestrogen receptor (%) < 0·001
< 10 2272 (12·5) 1562 (11·8) 710 (14·2)
≥ 10 15 867 (87·2) 11 583 (87·8) 4284 (85·6)
Unknown 49 (0·3) 40 (0·3) 9 (0·2)
HER2 status < 0·001
Negative 16 086 (88·4) 11 751 (89·1) 4335 (86·6)
Positive 1916 (10·5) 1281 (9·7) 635 (12·7)
Unknown 186 (1·0) 153 (1·2) 33 (0·7)
T category < 0·001
T1 14 302 (78·6) 10 854 (82·3) 3448 (68·9)
T2 3790 (20·8) 2264 (17·2) 1526 (30·5)
T3 85 (0·5) 57 (0·4) 28 (0·6)
Unknown 11 (0·1) 10 (0·1) 1 (0·0)
N category < 0·001
N0 12 649 (69·5) 9397 (71·3) 3252 (65·0)
N1 4220 (23·2) 2818 (21·4) 1402 (28·0)
N2 673 (3·7) 436 (3·3) 237 (4·7)
N3 313 (1·7) 226 (1·7) 87 (1·7)
Unknown 333 (1·8) 308 (2·3) 25 (0·5)
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Values in parentheses are percentages unless indicated otherwise;

*

values are mean(s.d.). BCS, breast‐conserving surgery; OPS, oncoplastic surgery; HER2, human epidermal growth factor receptor 2.

†

χ2 test, except

‡

Mann–Whitney U test.

OPS was performed with volume displacement in 4171 patients (83·4 per cent), volume reduction in 679 (13·6 per cent) and volume replacement in 153 (3·1 per cent). Patients who underwent OPS with volume reduction or replacement had lower co‐morbidity scores (P = 0·020), larger tumours (P < 0·001) and more lymph node involvement (P < 0·001) than those who had volume displacement (Table  2 ). Baseline characteristics of patients who underwent the three types of OPS are provided in Table  2 .

Table 2.

Baseline characteristics according to type of oncoplastic surgery

Volume displacement (n = 4171) Volume reduction (n = 679) Volume replacement (n = 153) P †
Year of operation
2012 658 (15·8) 113 (16·6) 38 (24·8) < 0·001
2013 536 (12·9) 119 (17·5) 26 (17·0)
2014 680 (16·3) 111 (16·3) 27 (17·6)
2015 609 (14·6) 88 (13·0) 20 (13·1)
2016 561 (13·5) 97 (14·3) 23 (15·0)
2017 583 (14·0) 72 (10·6) 8 (5·2)
2018 544 (13·0) 79 (11·6) 11 (7·2)
Age (years) * 60·1(11·5) 58·9(11·2) 57·4(10·3) < 0·001‡
Charlson Co‐morbidity Index score  0·020
0 3355 (80·4) 557 (82.0) 133 (86·9)
1 515 (12·3) 63 (9·3) 12 (7·8)
2 198 (4·7) 44 (6·5) 8 (5·2)
≥ 3 103 (2·5) 15 (2·2) 0 (0)
Histological finding  0·909
Ductal 3418 (81·9) 563 (82·9) 127 (83·0)
Lobular 456 (10·9) 75 (11·0) 18 (11·8)
Other 295 (7·1) 41 (6·0) 8 (5·2)
Unknown 2 (0.0) 0 (0) 0 (0)
Differentiation grade  0·071
I 963 (23·1) 131 (19·3) 32 (20·9)
II 1884 (45·2) 299 (44·0) 75 (49·0)
III 1010 (24·2) 204 (30·0) 37 (24·2)
Not determined 295 (7·1) 41 (6·0) 8 (5·2)
Unknown 19 (0·5) 4 (0·6) 1 (0·7)
Oestrogen receptor (%)  0·752
< 10 592 (14·2) 95 (14·0) 23 (15·0)
≥ 10 3570 (85·6) 584 (86·0) 130 (85·0)
Unknown 9 (0·2) 0 (0) 0 (0)
HER2 status  0·721
Negative 3620 (86·8) 581 (85·6) 134 (87·6)
Positive 522 (12·5) 94 (13·8) 19 (12·4)
Unknown 29 (0·7) 4 (0·6) 0 (0)
T category < 0·001
T1 3000 (71·9) 370 (54·5) 78 (51·0)
T2 1152 (27·6) 300 (44·2) 74 (48·4)
T3 18 (0·4) 9 (1·3) 1 (0·7)
Unknown 1 (0.0) 0 (0) 0 (0)
N category  0·006
N0 2749 (65·9) 417 (61·4) 86 (56·2)
N1 1134 (27·2) 215 (31·7) 53 (34·6)
N2 190 (4·6) 39 (5·7) 8 (5·2)
N3 74 (1·8) 7 (1·0) 6 (3·9)
Unknown 24 (0·6) 1 (0·1) 0 (0)
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Values in parentheses are percentages unless indicated otherwise;

*

values are mean(s.d.). HER2, human epidermal growth factor receptor 2.

†

χ2 test, except

‡

Kruskal–Wallis test.

In total, 2763 patients (15·2 per cent) underwent re‐excision, in whom the final surgical treatment was BCS in 2108 patients (76·3 per cent) and mastectomy in 655 (23·7 per cent). The re‐excision rate was 15·6 per cent for patients who underwent BCS and 14·1 per cent among those who had OPS (P = 0·012). Re‐excision rates varied according to OPS technique: 14·5 per cent for volume displacement, 10·3 per cent for volume reduction and 20·9 per cent for volume replacement (Table  3 ). The unadjusted re‐excision rate did not change significantly over time (P = 0·438).

Table 3.

Univariable and multivariable logistic regression analyses of characteristics predictive of re‐excision

Re‐excision Odds ratio†
No (n = 15 425) Yes (n = 2763) Univariable analysis (n = 18 188) Multivariable analysis (n = 18 188) P ‡
Type of surgery < 0·001
BCS 11 128 (84·4) 2057 (15·6) 1·00 (reference) 1·00 (reference)
Volume displacement 3567 (85·5) 604 (14·5) 0·92 (0·83, 1·01) 0·83 (0·75, 0·92)
Volume reduction 609 (89·7) 70 (10·3) 0·62 (0·48, 0·80) 0·50 (0·39, 0·65)
Volume replacement 121 (79·1) 32 (20·9) 1·43 (0·97, 2·12) 1·16 (0·78, 1·73)
Year of operation   0·202
2012 2295 (86·1) 372 (13·9) 1·00 (reference) 1·00 (reference)
2013 2332 (85·3) 401 (14·7) 1·06 (0·91, 1·24) 1·07 (0·92, 1·25)
2014 2330 (84·7) 421 (15·3) 1·12 (0·96, 1·30) 1·12 (0·96, 1·31)
2015 2208 (84·1) 418 (15·9) 1·17 (1·00, 1·36) 1·19 (1·02, 1·39)
2016 2144 (84·6) 389 (15·4) 1·12 (0·96, 1·31) 1·13 (0·97, 1·33)
2017 2083 (84·1) 393 (15·9) 1·16 (1·00, 1·36) 1·21 (1·04, 1·42)
2018 2033 (84·6) 369 (15·4) 1·12 (0·96, 1·31) 1·19 (1·01, 1·39)
Age (years) * 61·8(11·6) 59·9(11·2) 0·99 (0·98, 0·99) 0·99 (0·98, 0·99) < 0·001
Charlson Co‐morbidity Index score   0·061
0 11 790 (84·3) 2197 (15·7) 1·00 (reference) 1·00 (reference)
1 2148 (85·9) 352 (14·1) 0·88 (0·78, 0·99) 0·94 (0·83, 1·07)
2 962 (86·0) 156 (14·0) 0·87 (0·73, 1·04) 0·96 (0·81, 1·15)
≥ 3 525 (90·1) 58 (9·9) 0·59 (0·45, 0·78) 0·69 (0·52, 0·91)
Histological finding < 0·001
Ductal 12 614 (85·4) 2163 (14·6) 1·00 (reference) 1·00 (reference)
Lobular 1527 (80·9) 361 (19·1) 1·38 (1·22, 1·56) 1·40 (1·23, 1·59)
Other 1269 (84·3) 236 (15·7) 1·09 (0·94, 1·26) 1·45 (1·22, 1·71)
Unknown 15 (83·3) 3 (16·7) 1·17 (0·34, 4·03) 0·18 (0·04, 0·78)
Differentiation grade < 0·001
I 4246 (88·3) 563 (11·7) 1·00 (reference) 1·00 (reference)
II 6658 (83·7) 1300 (16·3) 1·35 (1·23, 1·48) 1·32 (1·19, 1·47)
III 3141 (83·8) 606 (16·2) 1·33 (1·19, 1·49) 1·18 (1·03, 1·36)
Not determined 1269 (84·3) 236 (15·7) – –
Unknown 111 (65·7) 58 (34·3) 3·61 (2·60, 5·00) 3·69 (2·57, 5·30)
Oestrogen receptor (%)   0·005
< 10 1902 (83·7) 370 (16·3) 1·10 (0·98, 1·24) 0·97 (0·85, 1·12)
≥ 10 13 490 (85·0) 2377 (15·0) 1·00 (reference) 1·00 (reference)
Unknown 33 (67·3) 16 (32·7) 2·75 (1·51, 5·01) 3·69 (1·66, 8·21)
HER2 status < 0·001
Negative 13 775 (85·6) 2311 (14·4) 1·00 (reference) 1·00 (reference)
Positive 1496 (78·1) 420 (21·9) 1·67 (1·49, 1·88) 1·60 (1·42, 1·81)
Unknown 154 (82·8) 32 (17·2) 1·24 (0·84, 1·82) 0·85 (0·52, 1·38)
T category < 0·001
T1 12 284 (85·9) 2018 (14·1) 1·00 (reference) 1·00 (reference)
T2 3097 (81·7) 693 (18·3) 1·36 (1·24, 1·50) 1·33 (1·20, 1·48)
T3 37 (43·5) 48 (56·5) 7·90 (5·13, 12·16) 7·16 (4·58, 11·18)
Unknown 7 (63·6) 4 (36·4) 3·48 (1·02, 11·89) 2·58 (0·64, 10·37)
N category < 0·001
N0 10 865 (85·9) 1784 (14·1) 1·00 (reference) 1·00 (reference)
N1 3501 (83·0) 719 (17·0) 1·25 (1·14, 1·38) 1·20 (1·09, 1·33)
N2 521 (77·4) 152 (22·6) 1·78 (1·47, 2·14) 1·51 (1·24, 1·84)
N3 243 (77·6) 70 (22·4) 1·75 (1·34, 2·30) 1·39 (1·05, 1·84)
Unknown 295 (88·6) 38 (11·4) 0·79 (0·59, 1·10) 0·75 (0·52, 1·09)
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Values in parentheses are percentages unless indicated otherwise;

*

values are mean(s.d.) and

†

values in parentheses are 95 per cent confidence intervals. BCS, breast‐conserving surgery; HER2, human epidermal growth factor receptor 2. †Adjusted for type of surgery, year of operation, age, histological finding, differentiation grade, oestrogen receptor, HER2 status, T and N category.

‡

Wald test.

Multivariable analysis showed that patients who underwent OPS were less likely to undergo re‐excision than those who had BCS (adjusted OR 0·80, 95 per cent c.i. 0·72 to 0·88). Subsequent analyses showed that patients who underwent OPS with volume displacement (OR 0·83, 0·75 to 0·92) or volume reduction (OR 0·50, 0·39 to 0·65) were less likely to undergo re‐excision than those who had BCS (Table  3 ). Patients who underwent OPS with volume replacement had the same likelihood of re‐excision as the BCS group (OR 1·16, 0·78 to 1·73).

Other characteristics associated with re‐excision were lobular or other histological subtype, higher differentiation grade, unknown oestrogen receptor status, positive HER2 status, larger tumour size and lymph node involvement (Table  3 ). Re‐excisions were less likely with increasing age. Year of surgery and co‐morbidity were not associated with re‐excision.

A shift from an imbalance in characteristics before propensity score matching to a balance after matching was observed when the BCS group was matched with the OPS group as a whole, and by type of OPS (Tables  S1 –S4, supporting information). In the matched cohort with OPS as a whole, re‐excision was less likely after OPS than BCS (OR 0·79, 0·71 to 0·88), similar to the results of multivariable analysis of the unmatched study population. Matched patients who underwent OPS with volume displacement (OR 0·80, 0·71 to 0·90) or volume reduction (0·46, 0·34 to 0·63) were less likely to undergo re‐excision than the BCS group, whereas patients who underwent OPS with volume replacement had the same likelihood of re‐excision as patients who had BCS (OR 1·13, 0·65 to 1·98).

Further analyses showed similar use of secondary interventions in patients older than 50 years undergoing BCS or OPS (16·4 versus 15·9 per cent; P = 0·430). However, among patients who had secondary interventions, boost radiation was used less often in patients who underwent BCS compared with those who had OPS (14·7 versus 21·2 per cent; P < 0·001).

In total, conversion to mastectomy was performed in 655 patients (3·6 per cent). The CMR was 3·7 and 3·2 per cent after BCS and OPS respectively (P = 0·105). Different CMRs were observed among the OPS techniques: 3·2 per cent for volume displacement, 2·9 per cent for volume reduction and 5·9 per cent for volume replacement. Over time, the unadjusted CMR decreased significantly from 4·3 to 2·7 per cent (P = 0·003) (Table S5, supporting information).

Multivariable analysis showed that patients who underwent OPS were less likely to undergo conversion to mastectomy than those who had BCS (OR 0·69, 0·58 to 0·84). Similar results were found for subgroups who had OPS with volume displacement (OR 0·71, 0·58 to 0·87) or volume reduction (OR 0·53, 0·33 to 0·84) (Table S5, supporting information). There was no difference in CMR between OPS with volume replacement and BCS (OR 1·07, 0·53 to 2·13). Conversion to mastectomy was more likely in patients with poor prognostic characteristics, including lobular histology (P < 0.001), larger tumour (P < 0·001) and more lymph node involvement (P < 0·001). In the matched cohorts (Tables  S1 –S4, supporting information), results of multivariable analyses were similar to those for the unmatched groups, in comparisons of OPS as a whole versus BCS (OR 0·70, 0·57 to 0·86), and OPS with volume displacement (OR 0·67, 0·54 to 0·84), volume reduction (OR 0·51, 0·30 to 0·89) or volume replacement (OR 1·13, 0·43 to 3·02) versus BCS.

Discussion

In this population‐based cohort study, re‐excision or conversion to mastectomy was less likely among patients who underwent OPS than BCS, although differences were modest. The re‐excision rate and CMR were lower among patients who underwent OPS using volume displacement and reduction techniques, but both rates were similar after BCS and OPS with volume replacement, although numbers in the latter group were small. This large population‐based study adjusted for confounders, and limited confounding by indication bias by means of propensity score matching.

Although no long‐term differences in recurrence rates and survival between BCS and OPS have been reported 13 , 19 , 22 , 43 , 44 , 45 , current evidence regarding the impact of OPS on the re‐excision rate is limited because the data are from single‐centre studies with relatively few patients undergoing OPS (ranging from 31 to 1177), and in most studies the methodology was weak 11 , 13 , 44 , 46 , 47 , 48 . The present results are in line with a meta‐analysis 19 from 2018 that found a significantly lower risk of re‐excision in patients who underwent OPS compared with those who had BCS (relative risk 0·66, 95 per cent c.i. 0·48 to 0·90). However, more recently, comparable re‐excision rates after BCS and OPS were reported in two studies from Finland 13 and Iceland 11 . In contrast to the present study, only relatively small numbers of patients were included, without extensive adjustment for confounders.

Since 2011, Danish guidelines 31 have stated that OPS should be considered when, for example, tumour size and location do not allow a satisfactory cosmetic result with BCS. In the present study, use of OPS among patients who underwent BCS decreased between 2012 and 2018 (from 30·3 to 26·4 per cent), specifically in volume reduction and replacement techniques. A large multicentre study 10 from the USA showed a significant rise in the OPS rate from 4·3 to 9·0 per cent between 2005 and 2016. Among those who underwent OPS, the percentage who had volume displacement was similar to that in the present study (85.2 and 83·4 per cent respectively). Nonetheless, the overall use of OPS here was still substantially higher than in most previous studies 18 , 19 .

Boost radiation is associated with serious side‐effects such as fibrosis, radiation heart disease and second non‐breast cancers 49 , 50 , and so re‐excision may have been preferred over boost radiation, specifically in patients with a tumour bed in front of the heart 51 . Nonetheless, in the present study, the rate of secondary interventions among patients older than 50 years was similar in those undergoing BCS and OPS, although boost radiation was preferred to re‐excision in the event of insufficient margins for those who underwent OPS. This was slightly surprising, as radiotherapy planning is challenging after OPS, because identification of the tumour bed can be difficult 52 . These findings highlight the challenge in balancing morbidity from re‐excision with that of boost radiation, and the importance of close collaboration between surgeons and radiation oncologists. Any decision regarding re‐excision or boost radiation should be made at a multidisciplinary team meeting.

Heterogeneous definitions of insufficient margins, ranging from ‘tumour within 10 mm from the ink margin’ to ‘tumour on ink’, may partly explain the difference between the findings here and those of other studies 18 , 19 . The present overall re‐excision rate of 15·2 per cent is within the range (0–15·7 per cent) reported in other studies 13 , 53 , 54 , 55 that used the same definition of ‘tumour on ink’. The associations between poor prognostic factors, such as larger tumour or lymph node involvement, and re‐excision and conversion to mastectomy are in line with previous findings 18 , 53 , 55 . Future guidelines may highlight the additional risk when considering OPS in these patients.

The overall CMR of 3·6 per cent in this analysis is well below the mean of 6·2 per cent and within the range of 0–34·2 per cent reported in previous studies, and a systematic review 18 of 55 studies. However, it is not in line with the results of a meta‐analysis 17 from 2014, which found a higher CMR for OPS with volume reduction and volume replacement compared with BCS. This may be explained partly by the fact that most included studies did not adjust for confounders and did not exclude patients diagnosed with in situ disease alone, because such patients are less likely to have a re‐excision rate similar to that for invasive breast cancer 56 .

The differing rates of re‐excision between OPS techniques might be explained by the small absolute numbers, and consequently wide confidence intervals. Another explanation could be differences in patient or tumour factors used for surgical procedure selection. Breast and tumour size, tumour location and glandular density are, among other factors, used in selection of the preferred OPS technique 16 , 57 , but also affect the likelihood of having a secondary mastectomy. For instance, patients with smaller breasts who require OPS with volume replacement may be less eligible for a secondary BCS, and may therefore undergo a secondary mastectomy when indicated.

The present data support the theory that OPS is associated with fewer re‐excisions, although other explanations are possible. Patients and surgeons might be less willing to accept re‐excisions following OPS because of the primary focus on the cosmetic result. Unfortunately, tumour margin data for the primary procedure are incomplete in the DBCG database for the early years of the present study and could therefore not be included.

Future studies should evaluate whether the effect of OPS on re‐excision is similar in patients treated with and without neoadjuvant therapy, as patients who are considered candidates for neoadjuvant therapy, such as those with locally advanced tumours 58 , are also candidates for OPS16. Neoadjuvant chemotherapy can be used for tumour downstaging, making more patients eligible for BCS without OPS. It could therefore be argued that there might be less need for OPS in the future as use of neoadjuvant chemotherapy in most high‐income countries has been increasing in recent years 8 , 57 . Neoadjuvant chemotherapy has only been used for breast cancer downstaging in Denmark more recently 59 , 60 , and patients receiving such treatment were not included in the present study. The increasing use of neoadjuvant chemotherapy might, however, explain the slight decrease in OPS in more recent years in this study.

That changing paradigm from primary BCS to more mastectomy seen in, for instance, the USA could also have influenced the present findings 61 . Earlier reports from the DBCG database, however, showed that the proportion of patients undergoing primary mastectomy remained stable at around 25 per cent in Denmark during the inclusion period of the present study 59 , 60 .

This study has several limitations. Several factors, such as breast size 22 , smoking status11 and surgeons' preference 62 , are known to affect both the choice of surgery and outcomes. Likewise, local resources (such as operating times) and level of experience among staff members can affect both the use of OPS and re‐excision rates. Unfortunately, information on these potential confounders was not available. Moreover, the rationale behind the choice of a specific surgical technique (such as racket mammoplasty or reduction with superior pedicle flap) is not registered by the DBCG. Residual confounding by indication could have been present as the matched analyses could only include available variables.

The present findings do not support the use of OPS in all patients undergoing BCS, but rather highlight the safety of OPS for those in whom a satisfactory cosmetic result could not be achieved with BCS alone. This study does not encourage the use of OPS in every patient, but emphasizes its appropriate use in selected patients who otherwise would not be eligible for breast conservation.

Supporting information

Table S1 Baseline characteristics of patients who underwent BCS and oncoplastic surgery before and after matching.

Table S2 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume displacement before and after matching.

Table S3 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume reduction before and after matching.

Table S4 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume replacement before and after matching.

Table S5 Univariable and multivariable analyses of characteristics predictive of conversion to mastectomy.

Click here for additional data file. (317.5KB, doc)

Acknowledgements

Study data can be made available upon reasonable request to the Scientific Committee of Surgery within the DBCG, and the Danish Clinical Registries. This study was supported by funding from the Stichting Professor Michaël‐van Vloten Foundation, Nijbakker‐Morra Foundation and the Leids University Foundation/Van Trigt Foundation.

Disclosure: The authors declare no conflict of interest.

References

  • 1. Blichert‐Toft M, Nielsen M, Düring M, Møller S, Rank F, Overgaard M et al Long‐term results of breast conserving surgery vs. mastectomy for early stage invasive breast cancer: 20‐year follow‐up of the Danish randomized DBCG‐82TM protocol. Acta Oncol 2008; 47: 672–681. [DOI] [PubMed] [Google Scholar]
  • 2. Litière S, Werutsky G, Fentiman IS, Rutgers E, Christiaens MR, Van Limbergen E et al Breast conserving therapy versus mastectomy for stage I–II breast cancer: 20 year follow‐up of the EORTC 10801 phase 3 randomised trial. Lancet Oncol 2012; 13: 412–419. [DOI] [PubMed] [Google Scholar]
  • 3. Veronesi U, Cascinelli N, Mariani L, Greco M, Saccozzi R, Luini A et al Twenty‐year follow‐up of a randomized study comparing breast‐conserving surgery with radical mastectomy for early breast cancer. N Engl J Med 2002; 347: 1227–1232. [DOI] [PubMed] [Google Scholar]
  • 4. Fisher B, Bauer M, Margolese R, Poisson R, Pilch Y, Redmond C et al Five‐year results of a randomized clinical trial comparing total mastectomy and segmental mastectomy with or without radiation in the treatment of breast cancer. N Engl J Med 1985; 312: 665–673. [DOI] [PubMed] [Google Scholar]
  • 5. Veronesi U, Saccozzi R, Del Vecchio M, Banfi A, Clemente C, De Lena M et al Comparing radical mastectomy with quadrantectomy, axillary dissection, and radiotherapy in patients with small cancers of the breast. N Engl J Med 1981; 305: 6–11. [DOI] [PubMed] [Google Scholar]
  • 6. Jensen MB, Ejlertsen B, Mouridsen HT, Christiansen P; Danish Breast Cancer Cooperative Group. Improvements in breast cancer survival between 1995 and 2012 in Denmark: the importance of earlier diagnosis and adjuvant treatment. Acta Oncol 2016; 55(Suppl 2): 24–35. [DOI] [PubMed] [Google Scholar]
  • 7.Integraal Kankercentrum Nedlerland (IKNL). Cijfers over kanker, overleving borstkanker 2017; 2017. https://www.cijfersoverkanker.nl/selecties/overleving_borst/img5acb2df1b4cee [accessed 1 December 2019].
  • 8. van Bommel A, Spronk P, Mureau M, Siesling S, Smorenburg C, Tollenaar R et al Breast‐contour‐preserving procedure as a multidisciplinary parameter of esthetic outcome in breast cancer treatment in The Netherlands. Ann Surg Oncol 2019; 26: 1704–1711. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9. Clough KB, Benyahi D, Nos C, Charles C, Sarfati I. Oncoplastic surgery: pushing the limits of breast‐conserving surgery. Breast J 2015; 21: 140–146. [DOI] [PubMed] [Google Scholar]
  • 10. Jonczyk MM, Jean J, Graham R, Chatterjee A. Surgical trends in breast cancer: a rise in novel operative treatment options over a 12 year analysis. Breast Cancer Res Treat 2019; 173: 267–274. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11. Palsdottir EP, Lund SHL, Asgeirsson KSA. Oncoplastic breast‐conserving surgery in Iceland: a population‐based study. Scand J Surg 2018; 107: 224–229. [DOI] [PubMed] [Google Scholar]
  • 12. Morrow ES, Stallard S, Doughty J, Malyon A, Barber M, Dixon JM et al Oncoplastic breast conservation occupies a niche between standard breast conservation and mastectomy – a population‐based prospective audit in Scotland. Eur J Surg Oncol 2019; 45: 1806–1811. [DOI] [PubMed] [Google Scholar]
  • 13. Niinikoski L, Leidenius MHK, Vaara P, Voynov A, Heikkilä P, Mattson J et al Resection margins and local recurrences in breast cancer: comparison between conventional and oncoplastic breast conserving surgery. Eur J Surg Oncol 2019; 45: 976–982. [DOI] [PubMed] [Google Scholar]
  • 14. Isaacs AJ, Gemignani ML, Pusic A, Sedrakyan A. Association of breast conservation surgery for cancer with 90‐day reoperation rates in New York state. JAMA Surg 2016; 151: 648–655. [DOI] [PubMed] [Google Scholar]
  • 15. Clough KB, van la Parra RFD, Thygesen HH, Levy E, Russ E, Halabi NM et al Long‐term results after oncoplastic surgery for breast cancer: a 10‐year follow‐up. Ann Surg 2018; 268: 165–171. [DOI] [PubMed] [Google Scholar]
  • 16. Clough KB, Kaufman GJ, Nos C, Buccimazza I, Sarfati IM. Improving breast cancer surgery: a classification and quadrant per quadrant atlas for oncoplastic surgery. Ann Surg Oncol 2010; 17: 1375–1391. [DOI] [PubMed] [Google Scholar]
  • 17. Losken A, Dugal CS, Styblo TM, Carlson GW. A meta‐analysis comparing breast conservation therapy alone to the oncoplastic technique. Ann Plast Surg 2014; 72: 145–149. [DOI] [PubMed] [Google Scholar]
  • 18. De La Cruz L, Blankenship SA, Chatterjee A, Geha R, Nocera N, Czerniecki BJ et al Outcomes after oncoplastic breast‐conserving surgery in breast cancer patients: a systematic literature review. Ann Surg Oncol 2016; 23: 3247–3258. [DOI] [PubMed] [Google Scholar]
  • 19. Chen JY, Huang YJ, Zhang LL, Yang CQ, Wang K. Comparison of oncoplastic breast‐conserving surgery and breast‐conserving surgery alone: a meta‐analysis. J Breast Cancer 2018; 21: 321–329. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20. Santos G, Urban C, Edelweiss MI, Zucca‐Matthes G, de Oliveira VM, Arana GH et al Long‐term comparison of aesthetical outcomes after oncoplastic surgery and lumpectomy in breast cancer patients. Ann Surg Oncol 2015; 22: 2500–2508. [DOI] [PubMed] [Google Scholar]
  • 21. Kelsall JE, McCulley SJ, Brock L, Akerlund MTE, Macmillan RD. Comparing oncoplastic breast conserving surgery with mastectomy and immediate breast reconstruction: case‐matched patient reported outcomes. J Plast Reconstr Aesthet Surg 2017; 70: 1377–1385. [DOI] [PubMed] [Google Scholar]
  • 22. Kelemen P, Pukancsik D, Újhelyi M, Sávolt Á, Kovács E, Ivády G et al Comparison of clinicopathologic, cosmetic and quality of life outcomes in 700 oncoplastic and conventional breast‐conserving surgery cases: a single‐centre retrospective study. Eur J Surg Oncol 2019; 45: 118–124. [DOI] [PubMed] [Google Scholar]
  • 23. Bodilsen A, Bjerre K, Offersen BV, Vahl P, Ejlertsen B, Overgaard J et al The influence of repeat surgery and residual disease on recurrence after breast‐conserving surgery: a Danish Breast Cancer Cooperative Group Study. Ann Surg Oncol 2015; 22(Suppl 3): S476–S485. [DOI] [PubMed] [Google Scholar]
  • 24. Jeevan R, Cromwell DA, Trivella M, Lawrence G, Kearins O, Pereira J et al Reoperation rates after breast conserving surgery for breast cancer among women in England: retrospective study of Hospital Episode Statistics. BMJ 2012; 345: e4505. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Dutch Institute for Clinical Auditing (DICA). Jaarrapportage 2017; 2018. http://dica.nl/jaarrapportage‐2017 [accessed 1 December 2019].
  • 26. Wanis ML, Wong JA, Rodriguez S, Wong JM, Jabo B, Ashok A et al Rate of re‐excision after breast‐conserving surgery for invasive lobular carcinoma. Am Surg 2013; 79: 1119–1122. [PubMed] [Google Scholar]
  • 27. Grant Y, Al‐Khudairi R, St John E, Barschkett M, Cunningham D, Al‐Mufti R et al Patient‐level costs in margin re‐excision for breast‐conserving surgery. Br J Surg 2019; 106: 384–394. [DOI] [PubMed] [Google Scholar]
  • 28. Dahlbäck C, Manjer J, Rehn M, Ringberg A. Determinants for patient satisfaction regarding aesthetic outcome and skin sensitivity after breast‐conserving surgery. World J Surg Oncol 2016; 14: 303. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29. Klit A, Tvedskov TF, Kroman N, Elberg JJ, Ejlertsen B, Henriksen TF. Oncoplastic breast surgery does not delay the onset of adjuvant chemotherapy: a population‐based study. Acta Oncol 2017; 56: 719–723. [DOI] [PubMed] [Google Scholar]
  • 30. Jensen MB, Laenkholm AV, Offersen BV, Christiansen P, Kroman N, Mouridsen HT et al The clinical database and implementation of treatment guidelines by the Danish Breast Cancer Cooperative Group in 2007–2016. Acta Oncol 2018; 57: 13–18. [DOI] [PubMed] [Google Scholar]
  • 31. Danish Breast Cancer Cooperative Group (DBCG). DBCG retningslinjer 2011; 2012. http://dbcg.dk/PDF%20Filer/Kap_4_Kirurgisk_behandling_03.04.13.pdf [accessed 1 December 2019].
  • 32. Schmidt M, Schmidt SA, Sandegaard JL, Ehrenstein V, Pedersen L, Sørensen HT. The Danish National Patient Registry: a review of content, data quality, and research potential. Clin Epidemiol 2015; 7: 449–490. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 33. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987; 40: 373–383. [DOI] [PubMed] [Google Scholar]
  • 34. Elston CW, Ellis IO. Pathological prognostic factors in breast cancer. I. The value of histological grade in breast cancer: experience from a large study with long‐term follow‐up. Histopathology 1991; 19: 403–410. [DOI] [PubMed] [Google Scholar]
  • 35. Wolff AC, Hammond ME, Hicks DG, Dowsett M, McShane LM, Allison KH et al; American Society of Clinical Oncology; College of American Pathologists. Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update. J Clin Oncol 2013; 31: 3997–4013. [DOI] [PubMed] [Google Scholar]
  • 36. Edge S, Byrd DR, Compton CC, Fritz AG, Greene F, Trotti A. AJCC Cancer Staging Handbook (7th edn), vol. XIX. Springer: New York, 2010. [Google Scholar]
  • 37. Danish Breast Cancer Cooperative Group (DBCG). Retningslinier Postoperativ strålebehandling 2016; 2016; http://dbcg.dk/PDF%20Filer/Kap%205%20Postoperativ%20straalebehandling%20‐%2022.06.2016.pdf [accessed 1 December 2019]. [Google Scholar]
  • 38. Bodilsen A, Bjerre K, Offersen BV, Vahl P, Amby N, Dixon JM et al Importance of margin width in breast‐conserving treatment of early breast cancer. J Surg Oncol 2016; 113: 609–615. [DOI] [PubMed] [Google Scholar]
  • 39. Austin PC. An introduction to propensity score methods for reducing the effects of confounding in observational studies. Multivariate Behav Res 2011; 46: 399–424. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40. Groenwold RH. [Propensity scores in observational research.] Ned Tijdschr Geneeskd 2013; 157: A6179. [PubMed] [Google Scholar]
  • 41. Austin PC. Comparing paired vs non‐paired statistical methods of analyses when making inferences about absolute risk reductions in propensity‐score matched samples. Stat Med 2011; 30: 1292–1301. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 42. Austin PC. Balance diagnostics for comparing the distribution of baseline covariates between treatment groups in propensity‐score matched samples. Stat Med 2009; 28: 3083–3107. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43. Mansell J, Weiler‐Mithoff E, Stallard S, Doughty JC, Mallon E, Romics L. Oncoplastic breast conservation surgery is oncologically safe when compared to wide local excision and mastectomy. Breast 2017; 32: 179–185. [DOI] [PubMed] [Google Scholar]
  • 44. Mazouni C, Naveau A, Kane A, Dunant A, Garbay JR, Leymarie N et al The role of oncoplastic breast surgery in the management of breast cancer treated with primary chemotherapy. Breast 2013; 22: 1189–1193. [DOI] [PubMed] [Google Scholar]
  • 45. Borm KJ, Schönknecht C, Nestler A, Oechsner M, Waschulzik B, Combs SE et al Outcomes of immediate oncoplastic surgery and adjuvant radiotherapy in breast cancer patients. BMC Cancer 2019; 19: 907. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 46. Chakravorty A, Shrestha AK, Sanmugalingam N, Rapisarda F, Roche N, Querci Della Rovere G et al How safe is oncoplastic breast conservation? Comparative analysis with standard breast conserving surgery. Eur J Surg Oncol 2012; 38: 395–398. [DOI] [PubMed] [Google Scholar]
  • 47. Carter SA, Lyons GR, Kuerer HM, Bassett RL Jr, Oates S, Thompson A et al Operative and oncologic outcomes in 9861 patients with operable breast cancer: single‐institution analysis of breast conservation with oncoplastic reconstruction. Ann Surg Oncol 2016; 23: 3190–3198. [DOI] [PubMed] [Google Scholar]
  • 48. Mukhtar RA, Wong J, Piper M, Zhu Z, Fahrner‐Scott K, Mamounas M et al Breast conservation and negative margins in invasive lobular carcinoma: the impact of oncoplastic surgery and shave margins in 358 patients. Ann Surg Oncol 2018; 25: 3165–3170. [DOI] [PubMed] [Google Scholar]
  • 49. Bartelink H, Maingon P, Poortmans P, Weltens C, Fourquet A, Jager J et al; European Organisation for Research and Treatment of Cancer Radiation Oncology and Breast Cancer Groups. Whole‐breast irradiation with or without a boost for patients treated with breast‐conserving surgery for early breast cancer: 20‐year follow‐up of a randomised phase 3 trial. Lancet Oncol 2015; 16: 47–56. [DOI] [PubMed] [Google Scholar]
  • 50. Grantzau T, Overgaard J. Risk of second non‐breast cancer after radiotherapy for breast cancer: a systematic review and meta‐analysis of 762 468 patients. Radiother Oncol 2015; 114: 56–65. [DOI] [PubMed] [Google Scholar]
  • 51. Taylor CW, Nisbet A, McGale P, Darby SC. Cardiac exposures in breast cancer radiotherapy: 1950s–1990s. Int J Radiat Oncol Biol Phys 2007; 69: 1484–1495. [DOI] [PubMed] [Google Scholar]
  • 52. Offersen BV, Boersma LJ, Kirkove C, Hol S, Aznar MC, Biete Sola A et al ESTRO consensus guideline on target volume delineation for elective radiation therapy of early stage breast cancer. Radiother Oncol 2015; 114: 3–10. [DOI] [PubMed] [Google Scholar]
  • 53. Clough KB, Gouveia PF, Benyahi D, Massey EJ, Russ E, Sarfati I et al Positive margins after oncoplastic surgery for breast cancer. Ann Surg Oncol 2015; 22: 4247–4253. [DOI] [PubMed] [Google Scholar]
  • 54. De Lorenzi F, Hubner G, Rotmensz N, Bagnardi V, Loschi P, Maisonneuve P et al Oncological results of oncoplastic breast‐conserving surgery: long term follow‐up of a large series at a single institution: a matched‐cohort analysis. Eur J Surg Oncol 2016; 42: 71–77. [DOI] [PubMed] [Google Scholar]
  • 55. Semprini G, Cattin F, Vaienti L, Brizzolari M, Cedolini C, Parodi PC. Oncoplastic surgery and cancer relapses: cosmetic and oncological results in 489 patients. Breast 2013; 22: 946–951. [DOI] [PubMed] [Google Scholar]
  • 56. Langhans L, Jensen MB, Talman MM, Vejborg I, Kroman N, Tvedskov TF. Reoperation rates in ductal carcinoma in situ vs invasive breast cancer after wire‐guided breast‐conserving surgery. JAMA Surg 2017; 152: 378–384. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 57. Rezai M, Knispel S, Kellersmann S, Lax H, Kimmig R, Kern P. Systematization of oncoplastic surgery: selection of surgical techniques and patient‐reported outcome in a cohort of 1035 patients. Ann Surg Oncol 2015; 22: 3730–3737. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 58. Holmes D, Colfry A, Czerniecki B, Dickson‐Witmer D, Francisco Espinel C, Feldman E et al Performance and practice guideline for the use of neoadjuvant systemic therapy in the management of breast cancer. Ann Surg Oncol 2015; 22: 3184–3190. [DOI] [PubMed] [Google Scholar]
  • 59.Danish Breast Cancer Cooperative Group (DBCG). Kvalitetsindikatorrapport for Brystkræft 2017; DBCG: Copenhagen, 2018.
  • 60.Danish Breast Cancer Cooperative Group (DBCG). Kvalitetsindikatorrapport for Brystkræft 2015 DBCG: Copenhagen, 2016.
  • 61. Lucas DJ, Sabino J, Shriver CD, Pawlik TM, Singh DP, Vertrees AE. Doing more: trends in breast cancer surgery, 2005 to 2011. Am Surg 2015; 81: 74–80. [PubMed] [Google Scholar]
  • 62. Carstensen L, Rose M, Bentzon N, Kroman NT. Knowledge and opinions on oncoplastic surgery among breast and plastic surgeons. Dan Med J 2015; 62: A5030. [PubMed] [Google Scholar]

Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Table S1 Baseline characteristics of patients who underwent BCS and oncoplastic surgery before and after matching.

Table S2 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume displacement before and after matching.

Table S3 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume reduction before and after matching.

Table S4 Baseline characteristics of patients who underwent BCS and oncoplastic surgery with volume replacement before and after matching.

Table S5 Univariable and multivariable analyses of characteristics predictive of conversion to mastectomy.

Click here for additional data file. (317.5KB, doc)

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