Comparing hookwire and wire-free localisation techniques in breast cancer surgery: oncological and patient-reported outcomes in a New Zealand cohort

Breast-conserving surgery is a cornerstone of early-stage breast cancer management, offering equivalent or potentially superior survival outcomes to mastectomy while preserving cosmesis and psychological wellbeing.^1,2 With growth of oncoplastic breast-conserving techniques and age extension of the New Zealand population–based breast screening programme in 2025, an increasing proportion of cancers are treated with breast-conserving surgery, necessitating accurate pre-operative localisation.^3,4

For decades, hookwire localisation (HWL) has been the standard technique for non-palpable breast lesion resection. First described in the 1970s, HWL involves percutaneous insertion of a wire under mammographic or ultrasound guidance, with the externalised wire guiding surgical excision.⁵ HWL remains widely practiced due to its accessibility, cost effectiveness and long safety record.

Despite its ubiquity, HWL has well-recognised limitations. Same-day wire placement ties operating theatre scheduling to radiology availability, which limits flexibility and often prevents early-morning starts. Patients must undergo the procedure while fasted, then wait for transfer between radiology and theatre suites, which can be physically uncomfortable and psychologically distressing.⁶ Technical challenges also include wire migration, wider resections than necessary, compromised cosmesis and higher re-excision rates.⁷ To address these limitations, wire-free localisation (WFL) devices have been developed, which can be placed days to weeks before surgery, decoupling localisation from operative timing, streamlining theatre workflow and improving patient comfort and anxiety.^8,9 In addition, WFL also facilitates targeted axillary dissection (TAD) after neoadjuvant chemotherapy, enabling selective excision of previously biopsied metastatic nodes to assess treatment response, all while reducing the risk of over-dissection, lymphoedema and nerve damage.¹⁰

Several WFL techniques have been developed, including radioactive approaches, such as radio-guided occult lesion localisation and radioactive seed localisation, and non-radioactive technologies, such as magnetic seed localisation, radiofrequency identification systems and radar-reflector localisation. In New Zealand, radio-iodine seed localisation was the first established form of WFL and was introduced in Waikato; however, wider national uptake was limited by the substantial administrative, regulatory and access requirements associated with handling radioactive substances.¹¹ This created a demand for non-radioactive alternatives. A rural centre, Gisborne, was the first in New Zealand to introduce non-radioactive WFL technology with Magseed^®, a magnetic seed localisation system. Other non-radioactive platforms subsequently adopted include Pintuition^®, which uses radiofrequency identification technology, and SAVI Scout^®, which uses radar-based reflector localisation.¹²

Prospective international cohort studies of Magseed and SAVI Scout report high rates of successful lesion retrieval, non-inferior margin outcomes compared with HWL, and improved patient satisfaction.^8,13,14 A Swedish randomised controlled trial has similarly demonstrated that WFL techniques deliver workflow advantages without compromising oncological outcomes.¹⁵ It is currently unclear whether a particular “brand” of WFL has clear advantages over the others.

In New Zealand, to date, no comparative series have been published in a local setting. This study from Middlemore Hospital provides contemporary New Zealand data directly comparing HWL and WFL, assessing surgical outcomes, reoperation for margin inadequacy and patient-reported satisfaction, as well that of the surgeons and radiologists involved, in a “real-world” setting.

Objectives

The primary objective of this study was to compare rates of reoperation for margin inadequacy, defined as re-excision and/or completion mastectomy, between patients undergoing HWL and those treated with WFL using seed-based technologies. The secondary objective was to evaluate patient-reported satisfaction using a structured questionnaire across four domains: overall experience, pain during localisation, procedure-related emotional distress and comfort while awaiting surgery. There was also a desire to collate radiologist and surgeon feedback in trialling the various brands of WFL technologies. Together, these outcomes were designed to capture both clinical effectiveness and patient-centred experience when comparing HWL and WFL in breast-conserving surgery.

Methods

Study design and setting

A cohort study was undertaken at Middlemore Hospital, New Zealand, with institutional research office approval. A prospective cohort of patients undergoing WFL using Magseed, Pintuition or SAVI Scout between March 2023 and June 2024 was compared with a retrospective cohort of patients who underwent HWL between March 2022 and February 2023. Although the cohorts were sequential rather than contemporaneous, temporal bias was considered minimal as there were no fundamental changes to breast service delivery, surgical practice, radiology workflow or margin assessment between the HWL period and the introduction of WFL. The HWL cohort was selected to approximate matching for age, ethnicity and tumour factors. The WFL sample size was determined by available funding for seed placement evaluation rather than an a priori power calculation. Selection bias was thus minimised as localisation technique was primarily determined by service availability and era of implementation rather than individual patient preference or selective allocation.

Inclusion and exclusion criteria

Prior to March 2023, all localisation at our institution was performed using hookwire techniques; accordingly, the HWL cohort was drawn from the year immediately preceding the introduction of WFL. From March 2023, the Middlemore breast surgery service commenced evaluation of WFL, and all patients from this date were eligible for seed localisation. However, recruitment in the WFL cohort was limited by the availability of funded seed placements during the evaluation period across the three brands of technologies.

Data collection

Data were collected prospectively in the WFL group and retrospectively in the HWL group, including demographics, tumour characteristics, localisation method, operative details, margin status and re-excision or mastectomy rates. Patient-reported outcomes were captured using a standardised five-point questionnaire delivered via text message with a free-text component. Responses were recorded on a Likert scale (strongly disagree=1, disagree=2, neutral=3, agree=4, strongly agree=5) across domains relating to pain acceptability, procedure-related distress, the experience of moving between hospital locations and waiting times. Likert responses were converted to a numerical score for statistical analysis. Radiologist and surgeon feedback was also collected. Free-text responses were reviewed descriptively to provide contextual feedback but were not subjected to formal qualitative analysis.

Statistical analysis

Continuous variables were reported as mean ± standard deviation or median (interquartile range) depending on distribution. Comparisons between groups were performed using Welch’s Two-Sample t-Test or the Mann–Whitney U test. Categorical variables were analysed using Pearson’s chi-squared test or Fisher’s exact test as appropriate. Patient satisfaction scores were specifically analysed using the Mann–Whitney U test at 95% significance. Statistical significance was set at p<0.05. All analyses were performed using R.

Results

Study cohort

A total of 216 patients were included, comprising 143 who underwent HWL and 73 who underwent WFL. No patient declined the option of seed localisation. Baseline characteristics were broadly comparable between cohorts. Mean age was 60 years in the HWL group and 58 years in the WFL group. Body mass index was slightly higher in the WFL cohort (33±9 vs 31±7). Ethnic representation across Māori, Pacific, Asian and European patients reflected the local population served by our institution.

The majority of patients presented via screening (HWL 84% vs WFL 81%). Diagnosis and cancer type were similar, with most patients having invasive disease with ductal carcinoma in situ. A higher proportion of WFL patients received neoadjuvant chemotherapy (16% vs 5.6%, p=0.019), possibly reflecting its integration into TAD protocols.

Within the WFL cohort, three localisation technologies were used: Magseed (n=17), Pintuition (n=30), and SAVI Scout (n=26). Most seed placements were performed to facilitate wide local excision (83%), with fewer for axillary localisation (9.9%) or combined breast and axillary indications (6.9%). Seed migration was uncommon, occurring in two cases within the Magseed sub-group.

Study data are summarised in Table 1.

Oncological outcomes (primary objective)

Following breast-conserving surgery, the rate of reoperation for margin inadequacy (re-excision and/or completion mastectomy) was 13% in the HWL group and 11% in the WFL group, with no statistically significant difference between cohorts (p=0.8).  Specimen weights were lower in the WFL group (87g vs 108g, p=0.4), despite comparable tumour sizes between cohorts and a trend towards slightly larger tumours in the WFL cohort.

Patient satisfaction (secondary objective)

The response rate to the anonymised questionnaire link, sent via text message by breast care nurses, was 66%. Patient-reported outcomes consistently favoured WFL over HWL across all measured domains. Mean overall experience scores were higher in the WFL cohort (4.50 vs 4.03, p=0.043). Notably, 35% of HWL patients reported dissatisfaction, defined as selecting “disagree” or “strongly disagree”, for at least one questionnaire item. Meanwhile, the WFL cohort described significantly greater comfort during localisation, as reflected in higher pain-free ratings (4.31 vs 3.68, p=0.012) and less psychological distress associated with the procedure (4.38 vs 3.66, p=0.0016). Patient comfort while awaiting surgery was also superior in the WFL group (4.47 vs 3.93, p=0.0015). In addition, multiple free-text comments received from HWL patients indicated discomfort and distress at the waiting time and the burden of same-day radiology placement. Free-text feedback from patients undergoing WFL was highly positive overall, with patients commonly reporting improved comfort, convenience and satisfaction.

Specialist preferences

From a technical perspective, radiologists reported Pintuition to be the easiest system to place accurately. Surgeons generally preferred SAVI Scout or Pintuition over Magseed, citing improved intraoperative usability and localisation confidence.

View Table 1.

Discussion

This study provides the first New Zealand comparative analysis of HWL and WFL for breast cancer surgery.

A key advantage of WFL is the ability to “decouple” radiological localisation from the day of surgery, a benefit that is highly relevant in both regional and metropolitan settings. In rural and regional centres, specialist breast radiology services may be intermittent or geographically remote, creating challenges with same-day wire placement. In metropolitan hospitals, WFL improves efficiency in high-volume services by reducing delays to first case start times and preventing bottlenecks when multiple operating lists compete for radiology availability. Furthermore, international studies suggest radiology turnaround times are shorter for seed placement compared with wire insertion, offering additional advantages in peri-operative workflow.^16,17

Oncological outcomes

Our findings are consistent with international data demonstrating that WFL achieves oncological outcomes that are at least non-inferior to HWL.^8,13,15 Several internationally published series have also reported lower reoperation rates for margin inadequacy with WFL, suggesting improved surgical precision.^5,7,18,19 If reproducible in New Zealand, this could represent a potential advantage in a resource-constrained health system, with cost savings through reduced re-excision and completion mastectomy rates.

Although our study was not powered to detect small differences in reoperation rates, our results demonstrated a similar trend to the international literature, with reoperation required in 13% of HWL cases compared with 11% of WFL cases (p=0.8). This may reflect more accurate lesion targeting using seed-based localisation, and is supported by a trend towards smaller specimen weights in the WFL group despite comparable (and slightly larger) tumour size. Smaller excision volumes may also translate into improved breast cosmesis, further strengthening the case for broader adoption of WFL.

Patient-reported outcomes

In terms of patient experience, WFL demonstrated clear superiority. Patients undergoing WFL reported significantly higher satisfaction across all measured domains, including overall experience, pain, psychological distress and comfort while awaiting surgery.

Cultural considerations

The ethnic distribution within our cohort reflected the diverse population served by our institution. This suggests that WFL is acceptable across a wide range of ethnic groups, including Māori and Pacific patients, supporting its broader applicability within the New Zealand healthcare context.

Other considerations

WFL also facilitates TAD following neoadjuvant chemotherapy. TAD involves selective removal of previously clipped, biopsy-proven metastatic lymph nodes, enabling accurate pathological assessment of treatment response while potentially avoiding the need for formal axillary clearance.¹⁰ By limiting the extent of axillary surgery, TAD has been associated with lower rates of lymphoedema, shoulder dysfunction and nerve injury compared with axillary lymph node dissection.²⁰ These benefits have important implications not only for long-term patient quality of life, but also for reducing downstream healthcare utilisation and improving overall system efficiency.

The decision regarding the brand of WFL (Magseed vs Pintuition vs SAVI Scout) is ultimately decided by surgeon and radiologist preference in each unit. However, in rural centres Magseed may have advantages because a related technique (with Magtrace^®) can be used for sentinel node biopsy, obviating the need for complex transfer of patients and/or radioisotope for these procedures. However, magnetic and paramagnetic localisation systems may be affected by interference from metallic surgical instruments and may require the purchase of additional non-magnetic instruments, which may be an important factor for cost.

Although a formal cost–benefit analysis was beyond the scope of this study, preliminary local accounting suggested cost neutrality for WFL use, driven by improved theatre scheduling, reduced reoperation rates and the ability to introduce TAD in appropriate post-neoadjuvant chemotherapy patients, rather than proceeding directly to axillary dissection.

Strengths and limitations

The strengths of this study include its real-world setting, direct comparison of HWL and WFL within the same institution and the inclusion of both oncological and patient-reported outcomes. The study further benefits from evaluating multiple WFL platforms (Magseed, Pintuition and SAVI Scout), allowing assessment of device performance in a New Zealand context. Various surgeons and radiologists utilised the technology; therefore, results withstand the variability introduced from various users and thus reflect the real world.

Several limitations should be acknowledged. The sample size was modest, limiting statistical power and precluding meaningful sub-group comparisons between individual WFL platforms. In addition, variation in questionnaire response rates and completeness may have influenced the consistency of patient-reported outcomes and introduced response or reporting bias. However, the direction of effect was consistent across all satisfaction domains, supporting the internal validity of the patient experience findings, and aligns with qualitative feedback routinely reported by the breast care nursing team.

Further international evidence is anticipated from the international multicentre MELODY study,²¹ which may give further insight of outcomes across different brands of WFL.

Conclusion

WFL is a safe and effective alternative HWL for non-palpable breast cancer surgery, and our results support wider adoption of WFL within New Zealand breast surgery centres. By decoupling localisation from the date of surgery, WFL offers flexibility in operating theatre scheduling and potential to improve cost efficiency, and significantly enhances the patient journey. WFL can be considered at least non-inferior to HWL for oncological outcome relating to margin status and need for second operations.