A comparative evaluation of ultrasound and frozen section analysis in predicting margin status after breast conservation surgery in patients with ultrasound-detectable breast cancer

Abstract

The primary goal of breast conservation surgery (BCS) is to achieve tumour-free margins. However, it is known that in 20% patients, a tumour-free margin may not be obtained. Positive margins frequently lead to re-operation and are the strongest predictors of local recurrence. We therefore evaluated the performance of ultrasound (US) and frozen section (FS) in predicting the margin status of lumpectomy specimens of ultrasound-detectable breast carcinoma patients undergoing BCS. In our prospective study on 54 patients who underwent lumpectomy, the margins were analyzed by ultrasound and frozen section. Patient-wise and margin-wise diagnostic parameters were calculated for both modalities.

Keywords

Breast carcinoma breast conservation lumpectomy frozen section analysis of lumpectomy specimen ultrasonography of lumpectomy specimen margin evaluation

Introduction

BCS is the standard of care for patients with early breast cancer, and even for some locally advanced breast cancers responding favourably to neoadjuvant chemotherapy (NACT). The primary goal of BCS is to achieve tumour-free margins. However, this may not be obtained on postoperative histopathological evaluation of lumpectomy specimens, which is the current gold standard for predicting the status of margins.¹

Positive margins lead almost inevitably to complications.^2–4 Visual inspection and palpation of the lumpectomy specimen is a universally applied intra-operative method for predicting tumour-free margins. Despite its inaccuracies, this method is a commonly used method of intraoperative margin evaluation.⁵ Besides being inexpensive and rapid, it does not require any specialized machinery or trained personnel other than the surgeon. The absence of a foolproof tool has also allowed many surgeons to continue with this method as the only tool for margin assessment during BCS. The absence, however, of a foolproof tool obliges a search for such a tool.

A host of modalities for intraoperative assessment of margins have been evaluated. These include specimen radiography (SR),⁶ US,^7–9 touch imprint cytology (TIC),¹⁰ FS,^11–13 micro-computerized tomography (micro-CT),¹⁴ ex vivo MRI imaging,^15,18 FDG-PET scan,¹⁶ optical coherence tomography (OCT),¹⁷ radiofrequency spectroscopy by MarginProbe Device,¹⁸ bioimpedance spectroscopy: ClearEdge Device,¹⁹ Raman spectroscopy combined with autofluorescence microscopy,²⁰ ultraviolet-photoacoustic microscopy (UV-PAM) and microscopy with ultraviolet surface excitation (MUSE).²¹

While some of these should be considered investigational or too costly for routine use at present, SR, USG, TIC, and FS have been evaluated by multiple studies and found to be at least moderately accurate in predicting the status of the lumpectomy margins.

TIC and FS analysis have shown promise but are not widely utilized as the requirement of a trained pathologist is obligatory and the increase in operative time is prohibitive. The installation and running costs of a cryostat are problematic in low and medium-income countries (LMICs).

Intraoperative ultrasonography of the lumpectomy specimen has the potential to offset these limitations, especially for breast cancers initially detected on ultrasound. It is widely available, has minimal running costs, is rapid, and can be performed by surgeons in the operating room itself after minimal training.

Materials and methods

Our prospective cross-sectional study included patients with ultrasound-detectable breast carcinoma amenable to BCS either primarily or post-NACT between September 2021 and March 2025. The study was approved by the Institute Ethics Committee (IEC: AIIMS/Pat/PGTh/July 20/24).

Patients were evaluated according to the standard protocol and staged by the 8^th AJCC manual. Patients with breast cancers not detectable on ultrasound (either primarily or after NACT) and patients who had multiple islands of residual tumours following NACT (found on imaging) were not included. All patients underwent wide local excision (WLE) of the tumour using palpation guidance with a > 1 cm margin (except where skin formed the anterior margin). The lumpectomy specimen was oriented with silk sutures [Fig. 1]. The status of the margins was assessed with ultrasonography [Fig. 1(a)] performed by a radiologist and then sent for frozen section analysis. The status of the margin was recorded in predesigned proforma and was mentioned to the surgeon once results of both modalities were available. Any margin < 2 mm on US was recorded as positive on ultrasound, while for FS, positive margins were defined as “ink on tumour”. If a margin was found to be involved using any modality, it was re-excised, and re-excised margins were again evaluated with the modality with which the lumpectomy margin was reported positive. The final margin status on haematoxylin and eosin (H & E) stained sections was considered the gold standard and results of ultrasonography and frozen section were compared against H&E section results. Statistical analysis was done using SPSS software (Version 24.0, Armonk, NY: IBM Corp.). Continuous variables were expressed as mean with standard deviation. Categorical variables were expressed as frequencies or percentages. The χ² test was used to determine an association between the two categorical variables. A p-value < 0.05 was considered statistically significant. We calculated the patient-wise and margin-wise sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for both modalities.

Results

A total of 54 consecutive patients with ultrasound-detectable breast carcinoma were included. Of these, 20 (37.0%) had received neoadjuvant chemotherapy to facilitate BCS. The clinico-pathologic profile of patients is presented in Table 1. The mean margin width reported on H&E sections (excluding the anterior margin) was 1.4 ± 0.9 cm.

Table 1.

Clinicopathological profile.

Parameters (n = 54)	Values (Percentage)
Age in years (mean ± SD)	45.6 ± 12.7
Menstrual status
Premenopausal	31 (57.4)
Postmenopausal	23 (42.5)
Clinical tumour size in cm (mean ± SD)	3.9 ± 2.0
Tumour stage (clinical)
cT1	05 (09.3)
cT2	30 (55.5)
cT3	14 (25.9)
cT4b	05 (09.3)
Neoadjuvant chemotherapy
No	34 (63.0)
Yes	20 (37.0)
Post-NACT clinical tumour size in cm (mean ± SD) (n = 11)	2.2 ± 2.1
^#Pathological tumor size in cm (mean ± SD)	2.6 ± 1.5
^@Tumour stage (Pathological)
pT1/ypT1	20 (37.0)
pT2/ypT2	34 (63.0)
^$Nodal stage (pathological)
pN0/ypN0	38 (70.4)
pN1/ypN1	16 (29.6)
Histology
Invasive ductal carcinoma- No specific subtype	50 (92.6)
Metaplastic carcinoma	04 (07.4)
*Mean margin width on HPE in cm (270 margins in 54 patients)	1.4 ± 0.9
IHC subtype
ER and/or PR positive, HER-2 negative	26 (48.1)
HER-2 positive	18 (33.3)
Triple-negative	10 (18.5)
Grade
I	18 (33.3)
II	30 (55.6)
III	06 (11.1)
Lymphovascular invasion
Yes	12 (22.2)
No	42 (77.8)

For patients receiving NACT, post-NACT pathological tumor size was taken.

For patients receiving NACT, post-NACT pathological tumor stage was taken.

For patients receiving NACT, post-NACT pathological nodal size was taken.

*Anterior margin width not included.

Patient-wise diagnostic parameters (Table 2) were calculated for all 54 patients for US, but it could only be done for 53 for FS because one margin in a patient turned out to be false positive and the other false negative. We also calculated the margin-wise diagnostic parameters. We did not include the results of anterior margins for these calculations; five margins for each of the 54 patients were analyzed (Table 3).

Table 2.

Patient-wise diagnostic parameters.

	US (n = 54)	FS (n = 53^#)
Sensitivity	75.0	100
Specificity	73.1	84.6
PPV	30.0	42.9
NPV	95.0	100
Accuracy	73.3	86.2

^# In one patient, one margin was false positive while the other was false negative on the frozen section, hence it was not analyzed to calculate patient-wise values.

Definitions: True positive- Positive margin detected with US or FS and same margin confirmed as positive on H & E section; True Negative- Negative margin detected with US or FS and same margin confirmed as negative on H & E section; False Positive- Positive margin detected with US or FS and same margin reported as negative on H & E section; False negative- Negative margin detected with US or FS and same margin reported as positive on H & E section.

Table 3.

Margin-wise diagnostic parameters (n = 270).

	US (n = 270)	FS (n = 270)
Sensitivity	85.6	87.5
Specificity	95.1	96.5
PPV	46.2	58.3
NPV	99.3	99.3
Accuracy	94.7	96.0

Definitions: True positive- Positive margin detected with USG or FS and same margin confirmed as positive on H & E section; True Negative- Negative margin detected with USG or FS and same margin confirmed as negative on H & E section; False Positive- Positive margin detected with USG or FS and same margin reported as negative on H & E section; False negative- Negative margin detected with USG or FS and same margin reported as positive on H & E section.

Discussion

FS had excellent patient-wise sensitivity of 100%, NPV of 100%, and a very acceptable specificity of 85%, because there were no false negatives. The margin-wise sensitivity (87.5%), specificity (96.5%), and NPV (99.3%) were also more than acceptable.

In comparison, the patient-wise sensitivity, NPV, and specificity of ultrasound were 75%, 95%, and 73.1%, while the margin-wise sensitivity, NPV, and specificity were 85.6%, 99.3%, and 95.1% respectively.

The most important concern while performing a BCS is to avoid positive margins during lumpectomy. Positive margins create anxiety in the patients, and confidence in the surgeon is often then lost. Furthermore, reoperation puts an extra burden on an already stressed healthcare delivery system and may also impact the cosmetic outcome.

Hence, the most important diagnostic parameter in our study was the NPV of US and FS. Having a high value of NPV means that there are fewer false negatives.²² US had a patient-wise NPV of 95% and a margin-wise NPV was 99.3% which was comparable to the values of FS (patient-wise NPV of 100% and a margin-wise NPV was 99.3%). The PPVs, both patient-wise and margin-wise, were low for both USG and FS, meaning that false positive rates would be higher using both these techniques.

A meta-analysis of the diagnostic accuracy of intraoperative techniques for margin assessment in breast conservation surgery including 35 studies found frozen section to be more accurate than ultrasound (pooled sensitivity, specificity, and area under the receiver operating characteristic curve of 86%, 96%, and 0.96 for frozen section versus 59%, 81%, and 0.78 for intraoperative ultrasound).²³ An older systematic review found frozen section to be an accurate modality, but consumed 20–30 min of extra time, while at a margin width of 2 mm, US had a 99.6% accuracy, with only a 4% second operation rate.²⁴

There is considerable evidence demonstrating the viability, dependability, safety, and cost-efficacy of the FS in margin assessment, although it is still not the standard of care. We routinely use FS at our institute and have little doubt about its accuracy. The only problem that we face is the prolonged waiting time for the FS results, which adds to the operative time and cost. Specimen ultrasound requires five minutes, is widely available, and has minimal operating cost. Although all US examinations were performed by a single experienced radiologist in the radiology department, US of specimens can be done in the operating room by surgeons with minimal training.^25,26

Various authors have employed different US margin widths to predict negative margins. Two recent studies reported excellent accuracy of US in predicting a negative margin when the margin width was ≥10 mm, one of those even reported a better accuracy of US than FS.^27,28 Other studies have used a margin of 2–5 mm to evaluate the accuracy of US in predicting margin status.^29–31 To the best of our knowledge, there are no published studies that have considered a margin narrower than 2 mm as a negative margin.

Conclusions

We conclude that US can be successfully used as a tool for margin assessment in patients undergoing BCS for US-detectable breast carcinomas.

Footnotes

Author contributions

Study concept and design: CKJ, SSP, JA, PPB

Acquisition of data: JA, SB, US

Analysis of data and interpretation: JA, SSP, CKJ

Drafting of the manuscript: CKJ, JA, SSP

Critical revision of the manuscript: PPB, SSP, US

Consent for publication

Written informed consent was obtained from all included patients for the publication of any potentially identifiable images or data included in this article.

Consent to participate

Written informed consent was obtained from all included patients.

Data availability

The datasets generated and analysed during the current study are available from the corresponding author upon reasonable request.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Ethical considerations

The study was conducted in accordance with the Declaration of Helsinki and was approved by the Ethics Committee of All India Institute of Medical Sciences, Patna (AIIMS/Pat/IEC/PGTh/July20/24) on September 09, 2021.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Prior presentation

A part of this study was presented as an abstract at the Sri Lanka Surgical Congress 2024.

ORCID iD

Chandan Kumar Jha

References

Lepomäki

Karhunen-Enckell

Tuominen

, et al. Tumor margins that lead to reoperation in breast cancer: a retrospective register study of 4,489 patients. J Surg Oncol 2022; 125: 577–588.

Veronesi

Cascinelli

Mariani

, 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.

Lichter

Lippman

Danforth

, et al. Mastectomy versus breast-conserving therapy in the treatment of stage I and II carcinoma of the breast: a randomized trial at the national cancer institute. J Clin Oncol 1992; 10: 976–983.

Litière

Werutsky

Fentiman

, 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.

Balch

Mithani

Simpson

, et al. Accuracy of intraoperative gross examination of surgical margin status in women undergoing partial mastectomy for breast malignancy. Am Surg 2005; 71: 22–27.

Jin

Kim

, et al. Intraoperative specimen mammography for margin assessment in breast-conserving surgery. J Breast Cancer 2019; 22: 635–640.

Krekel

NMA

Haloua

Lopes Cardozo

AMF

, et al. Intraoperative ultrasound guidance for palpable breast cancer excision (COBALT trial): a multicentre, randomised controlled trial. Lancet Oncol 2013; 14: 48–54.

Davis

Hsu

Bouton

, et al. Intraoperative ultrasound can decrease the re-excision lumpectomy rate in patients with palpable breast cancers. Am Surg 2011; 77: 720–725.

Doyle

Factor

Ellefson

, et al. High-frequency ultrasound for intraoperative margin assessments in breast conservation surgery: a feasibility study. BMC Cancer 2011; 11: 444.

10.

D’Halluin

Tas

Rouquette

, et al. Intra-operative touch preparation cytology following lumpectomy for breast cancer: a series of 400 procedures. Breast Edinb Scotl 2009; 18: 248–253.

11.

Olson

Harter

Muñoz

, et al. Frozen section analysis for intraoperative margin assessment during breast-conserving surgery results in low rates of re-excision and local recurrence. Ann Surg Oncol 2007; 14: 2953–2960.

12.

Rusby

Paramanathan

Laws

SAM

, et al. Immediate latissimus dorsi miniflap volume replacement for partial mastectomy: use of intra-operative frozen sections to confirm negative margins. Am J Surg 2008; 196: 512–518.

13.

Fukamachi

Ishida

Usami

, et al. Total-circumference intraoperative frozen section analysis reduces margin-positive rate in breast-conservation surgery. Jpn J Clin Oncol 2010; 40: 513–520.

14.

Janssen

NNY

van Seijen

Loo

, et al. Feasibility of micro-computed tomography imaging for direct assessment of surgical resection margins during breast-conserving surgery. J Surg Res 2019; 241: 160–169.

15.

Agresti

Trecate

Ferraris

, et al. Ex vivo MRI evaluation of breast tumors: a novel tool for verifying resection of nonpalpable only MRI detected lesions. Breast J 2013; 19: 659–663.

16.

Göker

Marcinkowski

Van Bockstal

, et al. 18F-FDG micro-PET/CT for intra-operative margin assessment during breast-conserving surgery. Acta Chir Belg 2020; 120: 366–374.

17.

Friedlander

Hibshoosh

, et al. Optical coherence tomography: a novel imaging method for post-lumpectomy breast margin assessment-A multi-reader study. Acad Radiol 2018; 25: 279–287.

18.

Schnabel

Boolbol

Gittleman

, et al. A randomized prospective study of lumpectomy margin assessment with use of MarginProbe in patients with nonpalpable breast malignancies. Ann Surg Oncol 2014; 21: 1589–1595.

19.

Dixon

Renshaw

Young

, et al. Intra-operative assessment of excised breast tumour margins using ClearEdge imaging device. Eur J Surg Oncol J Eur Soc Surg Oncol Br Assoc Surg Oncol 2016; 42: 1834–1840.

20.

Thomas

Nguyen

Pence

, et al. Evaluating feasibility of an automated 3-dimensional scanner using Raman spectroscopy for intraoperative breast margin assessment. Sci Rep 2017; 7: 13548.

21.

Wong

TTW

Zhang

Hai

, et al. Fast label-free multilayered histology-like imaging of human breast cancer by photoacoustic microscopy. Sci Adv 2017; 3: e1602168.

22.

Trevethan

. Sensitivity, specificity, and predictive values: foundations, pliabilities, and pitfalls in research and practice. Front Public Health 2017; 5: 307.

23.

St John

Al-Khudairi

Ashrafian

, et al. Diagnostic accuracy of intraoperative techniques for margin assessment in breast cancer surgery: a meta-analysis. Ann Surg 2017; 265: 300–310.

24.

Butler-Henderson

Lee

Price

, et al. Intraoperative assessment of margins in breast conserving therapy: a systematic review. Breast Edinb Scotl 2014; 23: 112–119.

25.

Barellini

Marcasciano

Lo Torto

, et al. Intraoperative ultrasound and oncoplastic combined approach: an additional tool for the oncoplastic surgeon to obtain tumor-free margins in breast conservative surgery-A 2-year single-center prospective study. Clin Breast Cancer 2020; 20: e290–e294.

26.

Chakedis

Tang

Kuehner

, et al. Implementation of intraoperative ultrasound localization for breast-conserving surgery in a large, integrated health care system is feasible and effective. Ann Surg Oncol 2021; 28: 5648–5656.

27.

Perera

Bourke

. The technique and accuracy of breast specimen ultrasound in achieving clear margins in breast conserving surgery. J Med Imaging Radiat Oncol 2020; 64: 747–755.

28.

Kumar

Tandon

Chintamani

. Intraoperative specimen ultrasonography: is it a reliable tool for margin assessment following breast conservation surgery for breast carcinoma? Cureus 2021; 13: e15806.

29.

Olsha

Shemesh

Carmon

, et al. Resection margins in ultrasound-guided breast-conserving surgery. Ann Surg Oncol 2011; 18: 447–452.

30.

Ramos

Díaz

Ramos

, et al. Ultrasound-guided excision combined with intraoperative assessment of gross macroscopic margins decreases the rate of reoperations for non-palpable invasive breast cancer. Breast Edinb Scotl 2013; 22: 520–524.

31.

Ramos

Díez

Ramos

, et al. Intraoperative ultrasound in conservative surgery for non-palpable breast cancer after neoadjuvant chemotherapy. Int J Surg Lond Engl 2014; 12: 572–577.