Intraoperative margin assessment in breast-conserving surgery. Preliminary analysis of cost-effectiveness and organisational benefits

Introduction

Breast cancer is a complex disease with a range of etiological factors [1, 2]. According to data from the National Cancer Registry, breast cancer was the most common malignant neoplasm among women in Poland in 2021. Published data on morbidity and mortality indicate a continuation of long-term increasing trends [3]. Given these epidemiological findings, the early detection of cancer is of paramount importance, as this can significantly improve patient prognosis [4, 5]. Breast-conserving surgery (BCS) is therefore the standard surgical procedure for treating early breast cancer, as it allows a satisfactory aesthetic outcome to be achieved while maintaining comparable oncological effectiveness to mastectomy [6–9]. A key aspect of the effectiveness of BCS is achieving surgical radicality, which is defined as the absence of cancer cells in the excision margins. Non-radical tumour removal is associated with an increased risk of local recurrence, which can be up to twice as high as in cases where negative margins were initially achieved [10]. Furthermore, numerous studies have shown that breast-conserving treatment results in a longer overall survival rate than mastectomy, particularly in women with early-stage breast cancer [11–13].

Intraoperative assessment of surgical margins in BCS is crucial to minimising reoperation rates. Over the past two decades, a number of methods have been implemented, encompassing classic histopathological techniques and innovative approaches utilising optical and spectroscopic imaging. Although this topic has been widely researched globally, relatively few publications have addressed this issue in Polish scientific literature [14, 15].

In the United States and Western Europe, the analysis of the postoperative specimens by intraoperative frozen section is commonly used and is characterised by high specificity (97%) and moderate sensitivity (65–78%) [16]. Concurrently, the imprint cytology technique is being developed in many centres as a faster, cheaper alternative that maintains comparable accuracy [16, 17].

Various academic centres have attempted to implement methods based on optical imaging, such as optical coherence tomography, or technologies utilising fluorescence or Raman spectroscopy. Although promising, their widespread use is limited due to high costs and equipment requirements [18–22].

Despite progress in intraoperative imaging techniques, the reoperation rate has not significantly decreased [23]. Reoperations, which are necessary to widen excision margins, pose an additional source of stress for patients and worsen the final aesthetic outcome [24]. They contribute to prolonged treatment time, increased hospitalisation costs and greater demand for operating theatres/rooms [25]. Therefore, to minimise the reoperation rate, it is crucial to continuously improve methods of surgical margin assessment during the primary procedure.

In this analysis, we present an evaluation of the effectiveness of intraoperative margin assessment in breast-conserving surgery, as conducted in our centre. The study aims to demonstrate the impact of this method on reducing the reoperation rate and analyse the resulting financial and organisational benefits.

Material and methods

For this retrospective analysis, we examined a cohort of 576 patients who underwent BCS at our centre between August 2016 and July 2023. The inclusion criteria for the study were defined to ensure the homogeneity of the analysed group and enable reliable conclusions to be drawn.

The study population consisted of patients with histologically confirmed invasive carcinoma or ductal carcinoma in situ of the breast, in whom an assessment of the surgical margins was performed intraoperatively during BCS. Patients who did not undergo intraoperative margin assessment, those who were eligible for mastectomy and those who were operated on in other centres were excluded from the analysis.

In 2016, our centre began using the IntraBeam system for intraoperative radiotherapy (IORT). A key criterion for qualifying for this treatment method was ensuring the radicality of tumour resection, as confirmed by the absence of tumour infiltration at the excision margins. To this end, we decided to implement intraoperative margin assessment based on a protocol similar to that used for Mohs micrographic surgery for skin cancers [26].

This procedure involves the ex-tempore collection of glandular tissue fragments from each surface remaining after breast tumour resection (most often three to five samples), which are then subjected to immediate histopathological examination in the Department of Pathomorphology/pathology department. The surgeon decides during the operation how wide the margins need to be removed. This depends on the size and location of the tumour and the type of surgery being performed. If the incision line runs close to the tumour, a margin is excised. Sometimes, aesthetic wound closure requires the removal of a wide tissue fragment adjacent to the tumour on any side. In such cases, a margin is not excised from this area because the resection is sufficiently wide and the risk of margin involvement is extremely low. One example is the ‘tennis racket’ technique, in which the peripheral edge of the tissue excision is usually distant from the tumour.

It was agreed with the pathology department that the excised margins would be about 5 mm thick. Given the additional margins that have been excised, there is no need for a wide excision of the main specimen. At the operating room/theatre, the outer surface (furthest from the tumour) of the margin is stained with ink. The entire margin is then rapidly frozen in a cryostat at –25°C. Ultrathin sections from the inked surface are collected, stained appropriately, and evaluated by a pathologist under a microscope.

It should be emphasised that the margins excised intraoperatively, after the ultrathin inked surface has been cut out, are then fixed in paraffin blocks in a standard manner and subjected to repeated, routine histopathological evaluation.

Although the procedure was developed for BCS with intraoperative radiotherapy, we have started using it in all conservative breast cancer surgeries.

For the economic analysis, reoperations resulting from non-radical excision in breast-conserving surgeries were classified under JGP group J02 (‘Complex breast procedures’), with an average point value of 6,613. According to the National Health Fund (NFZ) reimbursement scheme, the value of one point amounts to PLN 1.94 in centres without comprehensive oncological care and PLN 2.70 in centres with comprehensive oncological care.

For international comparison, monetary values were also converted into euros according to the National Bank of Poland’s exchange rate on 2 June 2025 (EUR 1 = PLN 4.2578).

Results

During the analysed period August 2016 – July 2023, a total of 549 BCS procedures involving intraoperative margin assessment were performed. The mean patient age was 61.44 years and the median was 63 years.

In the study group, 49.91% of patients underwent surgery on their left breast, and 49.18% underwent surgery on their right breast. Five patients (0.91%) underwent bilateral surgery. The mean observation time was 41.4 months and the median was 39 months, with a total observation period of 23–106 months.

Tumour size assessment showed a mean diameter of 1.78 cm (median 1.6 cm, range 0.1–9.0 cm) on ultrasound and 1.72 cm (median 1.5 cm, range 0.1–9.0 cm) on mammography. Clinical staging revealed that most patients presented with stage T1 (n = 271, 49.4%) or T2 (n = 208, 37.8%). Histopathological evaluation confirmed that invasive carcinoma of no special type was the most common subtype (n = 463, 84.3%).

In terms of molecular subtypes, the most common was luminal A (174 patients), followed by luminal B (140 patients), luminal HER2-positive (94 patients), non-luminal HER2-positive (43 patients), and triple- negative breast cancer (64 patients).

A total of 153 patients underwent neoadjuvant systemic therapy, while 14 patients received neoadjuvant endocrine therapy. Detailed characteristics are summarized in Table 1.

Detailed clinicopathological and demographic characteristics of the study group are presented in Table 1.

During these procedures, positive surgical margins were found in 70 cases. By widening the resection margins (repeated one to three times with each re-evaluation), negative margins were achieved in 55 cases, thus avoiding mastectomy and subsequent reoperation. Nevertheless, mastectomy was ultimately performed in 15 cases. Only four patients required reoperation due to tumour infiltration in the margins or an ambiguous result of the postoperative histopathological examination (Table 2).

Based on our subjective assessment, the observed number of local recurrences is comparable to the results of other studies [27, 28]. However, this parameter was not subject to detailed analysis in this paper and will be thoroughly evaluated in a separate upcoming publication.

Avoiding reoperation in 70 patients resulted in significant financial savings. The average cost of one reoperation was estimated at PLN 12,829 (approximately EUR 3,013) in centres without comprehensive oncological care and PLN 17,855 (approximately EUR 4,194) in centres with comprehensive oncological care. Accordingly, the total savings were PLN 898,045 (approximately EUR 210,918) and PLN 1,249,857 (approximately EUR 293,545), respectively (Table 3).

Discussion

Although there are reports in the Polish medical literature on the assessment of intraoperative margins in breast cancer [14, 15], this analysis provides a unique evaluation of the results of applying this method over a longer period and considers its impact on reoperation rates and the economic and organisational implications.

In our cohort, positive surgical margins were identified in 12.8% of patients, which is within the 10–20% range reported in large meta-analyses [10, 23]. Thanks to repeated intraoperative re-excisions, negative margins were ultimately achieved in the majority of cases, demonstrating the clinical effectiveness of this approach. The reoperation rate in our study was only 0.7%, which is markedly lower than the 5–15% rates reported in European and North American studies [23, 29]. These findings confirm that the systematic use of intraoperative frozen section analysis can significantly reduce the need for secondary surgical procedures.

A key organisational benefit of intraoperative margin assessment is the reduction in surgeons’ workload [29, 30]. Each avoided reoperation not only avoids an additional, often unplanned, procedure, but also frees up valuable operating time. Furthermore, fewer unplanned radicalisation mean greater availability of operating slots for new patients. Optimising operating room utilisation and human resources helps to streamline patient flow through the healthcare system. Reducing waiting times for treatment is also extremely important from the patients’ perspective, and faster initiation of therapy can positively impact prognosis.

It should also be noted that the technique for preparing specimens has evolved over time to encompass various methods of inking, freezing and sectioning tissue. Currently, the total duration of the preparation and immediate assessment procedure is approximately 30 minutes. On average, it takes about 40 minutes from margin collection to the surgeon obtaining the result. During this period, the surgeon usually performs a sentinel lymph node biopsy and, if necessary, prepares the tumour bed for intraoperative radiotherapy. In our experience, these activities do not significantly prolong the duration of surgery in patients undergoing intraoperative radiotherapy. This demonstrates that intraoperative margin assessment can be effectively integrated into the surgical workflow without materially increasing operative time.

The absence of the need for another operation to achieve a clear margin eliminates the additional stress and anxiety for patients associated with the prospect of another surgical procedure. Avoiding reoperation also shortens treatment time and enables patients to return to normal daily activities without the need for readmission, convalescence and potential postoperative complications. Additionally, achieving surgical radicality in a single procedure minimises the risk of worsening the aesthetic outcome of the breast, which could result from subsequent surgical intervention. Patients can more quickly accept their appearance after surgery and resume normal social and emotional functioning, significantly improving their quality of life [9, 24].

The total cost of potential reoperations for this group of patients was 436,458 points (66 patients × 6,613 points per patient). It should be emphasised that this amount represents real savings for the healthcare system [29, 30], resulting from the elimination of costs associated with additional hospitalisation, surgical procedures and potential complications. Further savings resulting from performing other surgical procedures instead of reoperations related to positive tumour resection margins are beyond the scope of this study, but seem obvious.

It should be emphasised, however, that intraoperative margin assessment does not generate direct financial benefits for the hospital. On the contrary, it requires additional workload and resources from the pathology department. The true economic advantage of this approach is observed primarily at the healthcare system level, where avoiding reoperations translates into reduced costs of repeated hospitalisations, surgical procedures, and potential complications, while also improving the overall patient experience.

Similar conclusions have been reached in studies conducted at various centres analysing the application of intraoperative margin assessment using the frozen section method. These studies indicated that introducing this procedure can reduce the number of reoperations and provide tangible organisational and economic benefits to the healthcare system [29, 30].

Conclusions

Intraoperative margin assessment in BCS is an effective strategy that minimises the need for reoperation and supports the achievement of oncological radicality during the primary procedure. Beyond/Apart from the direct clinical benefits, this approach optimises the use of healthcare resources by reducing the number of repeated interventions. The economic analysis highlights its potential to generate significant cost savings for the healthcare system. These findings support the broader implementation of intraoperative margin assessment protocols in clinical practice.

Future studies with extended follow-up, including the use of a control group and a comparison of patients treated with and without IORT, are planned in order to better assess long-term oncological outcomes and further validate the economic advantages of this method.