Radiofrequency ablation of small breast tumours: Evaluation of a novel bipolar cool-tip application

Non-surgical ablation for breast cancer: an emerging therapeutic option

Non-surgical ablation is emerging as an alternative local therapy option for patients with early-stage breast cancer and encompasses two main types of percutaneous therapeutic procedures: radiofrequency ablation and cryoablation. Both techniques involve obliteration of a spherical lesion and feasibility studies have shown that complete tumour ablation is achievable with good or excellent cosmetic results. Although few clinical studies have directly compared non-surgical ablation with conventional surgical resection, observational studies indicate that clinical outcomes are favourable with acceptable rates of local control and no detriment to long-term survival. There remain outstanding issues with these percutaneous ablative techniques that require resolution before they could be incorporated into routine clinical practice. Hence, a consensus meeting was convened to discuss the challenges of non-surgical ablation and clarify indications for its use alongside clinical management pathways. In this Policy Review we will address some of the broader biological aspects of non-surgical ablation, including immune-modulatory effects and potential novel applications for the future.

Percutaneous Management of Breast Cancer: a Systematic Review

PURPOSE OF REVIEW

Surgical treatment of breast cancer is becoming increasingly more minimally invasive. We review the development status of percutaneous management for primary breast cancer and the evidence relating to tumor size as a fundamental determinant of treatment clinical outcome.

RECENT FINDINGS

It is safe and feasible for percutaneous management to treat breast cancer. For tumor size ≤ 2 cm, percutaneous management is a promising alternative modality. For tumor size ≤ 3 cm, it is controversial whether percutaneous management can achieve similar effects to surgery, especially its long-term effects. For tumor size > 3 cm, it is still in the initial exploration stage and showed the potential in the treatment of unresectable cancer by benefitting the local control of primary cancer. Percutaneous management of breast cancer is a valuable method for breast cancer treatment in selected patients. However, it will be necessary to provide the high level of evidence for widespread clinical application.

Efficacy and Safety of Radiofrequency Ablation for Breast Cancer Smaller Than 2 cm: A Systematic Review and Meta-Analysis

Background

To evaluate the efficacy and safety of radiofrequency ablation (RFA) of breast cancer smaller than 2 cm.

Methods

A systematic search was conducted in the PubMed and EMBASE databases to identify published studies investigating the efficacy and safety of RFA for breast cancer smaller than 2 cm. The main outcomes were technical success rate of the ablation, complete ablation rate, complications and local recurrence. Secondary considerations were mode of anesthesia, pain tolerance, mean ablation time and surgical excision after ablation.

Results

Seventeen studies involving 399 patients and 401 lesions met the inclusion criteria. Nearly 99%(95%CI=0.98-1.00) of lesions achieved good technical success rate.Notably, 83.88% of the patients received RFA under general anesthesia (333/397) whereas 15.87% received RFA under local anesthesia (63/397). Of the 63, 98.41% tolerated the pain associated with the procedure. Majority of patients (65.74%, 261/397) underwent surgical excision of the tumor after ablation whereas in a few patients (34.26%, 136/397), the tumor tissue was retained in the breast after ablation. Complete ablation was achieved in 96% of patients for a mean time of 15.8 minutes (95%CI=0.93-0.99). Overall, only 2% (95%CI=0.01-0.04) of the individuals developed complications. Skin burns (2.02%, 8/397) were the most common complications. There was no local recurrence after a median follow-up of 27.29 months, whether or not they underwent surgical resection following RFA.

Conclusion

The results show that RFA for breast cancer smaller than 2 cm is safe and effective. However, prospective studies are needed to validate this conclusion.

Thermal Ablation as an Alternative for Surgical Resection of Small (≤ 2 cm) Breast Cancers: A Meta-Analysis

Women with early-stage breast cancer have an excellent prognosis with current therapy, but could presumably be treated less invasively, without the need for surgery. The primary goal of this meta-analysis was to examine whether thermal ablation is an effective method to treat early-stage breast cancer. Studies reporting on complete ablation rate after thermal ablation as a treatment of small breast cancers (≤ 2 cm) were included. Methodologic quality of included studies was assessed using MINORS criteria. Complete ablation rates are given as proportions, and meta-regression and subgroup analyses were performed. The overall complete ablation rate in 1266 patients was 86% and was highest after radiofrequency ablation (RFA) (92%). Local recurrence rates varied from 0% to 3%, with a median follow-up of 15 to 61 months. Overall, complication rates were low (5%-18% across techniques) and were highest after high-intensity focused ultrasound ablation and lowest after cryoablation. Cosmetic outcome was good to excellent in at least 85% of patients but was reported infrequently and long-term results of cosmetic outcome after thermal ablation and radiotherapy are still lacking. Thermal ablation techniques treating early-stage breast cancer (≤ 2 cm) are safe and effective based on complete ablation rate and short-term local recurrence rates. Especially, RFA, microwave ablation, and cryoablation are promising techniques as an alternative to surgical resection without jeopardizing current treatment effectiveness or safety. Owing to great heterogeneity in the included studies, a formal recommendation on the best technique is not possible. These findings warrant the design of large randomized controlled trials comparing thermal ablation and breast-conserving surgery in the treatment of T1 breast cancer.

Subsequent cooling-circulation after radiofrequency and microwave ablation avoids secondary indirect damage induced by residual thermal energy

PURPOSE

We aimed to investigate the exact role of residual thermal energy following microwave ablation (MWA) and radiofrequency ablation (RFA) at the final ablation and transition zones and determine whether residual thermal energy could be dissipated by subsequent cooling-circulation.

METHODS

In an ex vivo study, MWA and RFA were performed on fresh porcine liver, and central and border temperatures were compared. In an in vivo study, MWA and RFA were performed to the livers of New Zealand white rabbits. Tissue samples were stained with α-NADH-diaphorase. The coagulation zones (NADH-negative) and transition zones (lightly NADH-stained) of different groups were compared at different time points.

RESULTS

In the ex vivo model, the residual thermal energy after MWA and RFA could be dispersed by subsequent cooling-circulation due to the temperature decreasing rapidly. In the in vivo study, the coagulation volume in the ablation group was larger than that in the cooling-circulation group (P < 0.05) 2 days after ablation. In the ablation group, the damaged zone (the transition zone plus the coagulation zone) on α-NADH-diaphorase-stained images increased rapidly within 2 hours after ablation and slowly reached the maximum on day 2. However, the damaged zones did not change significantly at the three time points observed in the cooling-circulation group.

CONCLUSION

The residual thermal energy in MWA and RFA induced secondary damage beyond the direct coagulation zone, and it could be dissipated by subsequent cooling-circulation, contributing to smaller ablation and transition zones.

Clinical application of ultrasound-guided percutaneous microwave ablation for benign breast lesions: a prospective study

BACKGROUND

Background: Benign breast lesions are the most common diseases in adult women, which have been treated with minimally invasive therapies in recent years. Little is known about the feasibility of Microwave ablation (MWA) for benign breast lesion treatment. The primary aim of this prospective study was to evaluate the safety and efficiency of MWA as a potential therapeutic option for benign breast lesions in a single-center cohort study.

METHODS

Women with possibly benign breast lesions based on an ultrasound (US) assessment who were scheduled to undergo MWA between November 2014 to July 2018 were included in the study. The patients underwent conventional US to measure the size of the lesion, Doppler US to assess the vascularity of the lesion, elastography to evaluate the stiffness of the mass, core needle biopsy of suspicious lesions, contrast-enhanced US to help determine the treatment plan and eventually MWA of the lesion. Lesions were followed at one, three, six, twelve and eighteen months after treatment to with the same imaging modalities.

RESULTS

A total of 314 women aged 17 to 69 years old (mean = 36.9 ± 9.9 years) with 725 benign breast lesions (mean of maximum diameter = 10.86 ± 5.40 mm) were included. The frequency of palpable mass, pain and nipple discharge significantly decreased after treatment. Complete ablation rate was 97.8%, immediately after ablation, which increased to 100% after supplementary ablation of the 15 cases with incomplete ablation. Blood flow classification and lesion's volume also showed a significant decrease, while both volume reduction ratio and disappearance rate significantly increased following treatment. The elasticity score of the lesions showed fluctuations across different follow-up intervals. None of the patients experienced major complications and the 1% who had mild symptoms were successfully treated.

CONCLUSION

MWA treatment is shown to be safe and efficient and has the potential to be considered as an alternative first line treatment for benign breast lesions.

Microwave ablation of benign breast tumors: a prospective study with minimum 12 months follow-up

PURPOSE

This prospective study was to evaluate clinical outcomes of microwave ablation (MWA) of benign breast tumors with minimum 12 months follow up.

METHODS

With approval of the institutional ethics committee and written informed consent, 56 patients with 107 biopsy-proved breast benign tumors were recruited from November, 2013 to April, 2017. MWA with ultrasound (US) guidance was performed under local anesthesia. During the procedure, pull-back technique was used for tumors larger than 1.0 cm in diameter and hydro-dissection technique was used for tumors adjacent to skin, pectoralis and areola. Clinical outcomes were followed up by physical examination and medical images including US, contrast enhanced US and MR.

RESULTS

The maximum diameter of these tumors was 1.6 ± 0.8 cm. MWA was successfully performed with the median 120 s of duration (ranging 20-1100 s). Technical success was achieved in all patients. At the median follow-up of 20.5 months (ranging 12-53 months), the mean volume reduction ratios (mVRRs) of tumors were 77.1 ± 8.2%, 84.3 ± 10.6%, 93.3 ± 8.2% at follow-up of 12, 18, 24 months (p < .0001), respectively. Compared with 92% of masses were palpable before ablation, mass palpabilities were 40%, 11%, 5% at follow-up of 12, 18, 24 months (p < .001), respectively. Cosmetic satisfaction was reported excellent or good in 100% of patients.

CONCLUSIONS

As a safe and effective minimally invasive modality for inactivating benign breast tumors in situ, MWA achieved optimistic clinical outcomes on volume reduction and cosmetic satisfaction after minimum 12 months follow-up.

Ultrasound-guided percutaneous microwave ablation for benign breast lesions: evaluated by contrast-enhanced ultrasound combined with magnetic resonance imaging

Background

Minimally invasive ablative techniques in the treatment of breast tumor has become popularly in recent years.

Methods

We analyzed gray-scale and contrast-enhanced ultrasound (CEUS) features of 205 microwave ablated breast benign lesions from 182 consecutive patients, compared with magnetic resonance imaging (MRI) and histopathology findings. The follow-up was implemented at 3, 6 and 12 months after the ablation treatment.

Results

Before the MWA, the mean of largest diameter and volume of the lesions were 14.41±6.54 and 3,224±961 mm³, respectively. However, those of the lesions respectively were 8.48±6.30 and 2,116±732 mm³ one year after the treatment. The longest diameter and the volume of the ablative lesions were gradually decreased 3, 6 or 12 months after the MWA. 44 (/205, 21.5%) ablative lesions were disappeared one year after the MWA. One hundred and forty-two (/205, 69.3%) ablative lesions presented a hypoechoic halo surrounding it on gray-scale US after the MWA. The success rate of the MWA treatment in the benign breast lesion was 87.32% and 82.93% evaluated by CEUS and enhanced MRI, respectively. During the ablation, no patient had serious complications, such as hemorrhage, serious pain and fat necrosis, etc.

Conclusions

Microwave ablation was a safe and efficient method in the treatment of the benign breast tumors. CEUS and enhanced MRI could accurately assess whether the MWA treatment is effective.

Early health technology assessment of magnetic resonance-guided high intensity focused ultrasound ablation for the treatment of early-stage breast cancer

BACKGROUND

Magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) ablation is in development for minimally invasive treatment of breast cancer. Cost-effectiveness has not been assessed yet. An early health technology assessment was performed to estimate costs of MR-HIFU ablation, compared to breast conserving treatment (BCT).

METHODS

An MR-HIFU treatment model using the dedicated MR-HIFU breast system (Sonalleve, Philips Healthcare) was developed. Input parameters (treatment steps and duration) were based on the analysis of questionnaire data from an expert panel. MR-HIFU experts assessed face validity of the model. Data collected by questionnaires were compared to published data of an MR-HIFU breast feasibility study. Treatment costs for tumours of 1 to 3 cm were calculated.

RESULTS

The model structure was considered of acceptable face validity by consulted experts, and questionnaire data and published data were comparable. Costs of MR-HIFU ablation were higher than BCT costs. MR-HIFU best-case scenario costs exceeded BCT costs with approximately €1000. Cooling times and breathing correction contributed most to treatment costs.

CONCLUSIONS

MR-HIFU ablation is currently not a cost-effective alternative for BCT. MR-HIFU experience is limited, increasing uncertainty of estimations. The potential for cost-effectiveness increases if future research reduces treatment durations and might substantiate equal or improved results.

Patient Preferences for Minimally Invasive and Open Locoregional Treatment for Early-Stage Breast Cancer

BACKGROUND

Noninvasive or minimally invasive treatments are being developed as alternatives to surgery for patients with early-stage breast cancer. Patients' preferences with regard to these new treatments have not been investigated.

OBJECTIVES

To assess preferences of patients with breast cancer and of healthy women regarding these new techniques, compared with conventional surgical treatments.

METHODS

Six hypothetical breast cancer treatment-outcome scenarios were developed: three standard surgical scenarios (mastectomy, mastectomy with immediate implant-based reconstruction, and breast-conserving therapy [BCT]) and three minimally invasive or noninvasive scenarios (radiofrequency ablation, magnetic resonance-guided high-intensity focused ultrasound ablation, and single-dose ablative radiotherapy). Participants rated treatment-outcome scenarios by visual analogue scale (VAS) and time trade-off (TTO). The Friedman and post hoc Wilcoxon signed-rank tests were used to test whether scores were significantly different from BCT.

RESULTS

Seventy-one patients with breast cancer and 50 healthy volunteers participated. Overall, BCT was rated the highest in terms of VAS (0.80) and TTO (0.90) scores. After stratification, BCT ranked the highest in most subgroups, with the exception of healthy individuals, who had given the highest score to ablative boost (VAS, 0.80; TTO, 0.88). Mastectomy with immediate reconstruction was the least preferred in most subgroups.

CONCLUSIONS

This study showed no significant preference for minimally invasive treatment for breast cancer. Using hypothetical scenarios, breast cancer survivors attributed the highest scores to BCT, whereas healthy volunteers showed a slight preference for minimally invasive treatments.

Technical success, technique efficacy and complications of minimally-invasive imaging-guided percutaneous ablation procedures of breast cancer: A systematic review and meta-analysis

OBJECTIVES

To systematically review studies concerning imaging-guided minimally-invasive breast cancer treatments.

METHODS

An online database search was performed for English-language articles evaluating percutaneous breast cancer ablation. Pooled data and 95% confidence intervals (CIs) were calculated. Technical success, technique efficacy, minor and major complications were analysed, including ablation technique subgroup analysis and effect of tumour size on outcome.

RESULTS

Forty-five studies were analysed, including 1,156 patients and 1,168 lesions. Radiofrequency (n=577; 50%), microwaves (n=78; 7%), laser (n=227; 19%), cryoablation (n=156; 13%) and high-intensity focused ultrasound (HIFU, n=129; 11%) were used. Pooled technical success was 96% (95%CI 94-97%) [laser=98% (95-99%); HIFU=96% (90-98%); radiofrequency=96% (93-97%); cryoablation=95% (90-98%); microwave=93% (81-98%)]. Pooled technique efficacy was 75% (67-81%) [radiofrequency=82% (74-88); cryoablation=75% (51-90); laser=59% (35-79); HIFU=49% (26-74)]. Major complications pooled rate was 6% (4-8). Minor complications pooled rate was 8% (5-13%). Differences between techniques were not significant for technical success (p=0.449), major complications (p=0.181) or minor complications (p=0.762), but significant for technique efficacy (p=0.009). Tumour size did not impact on variables (p>0.142).

CONCLUSIONS

Imaging-guided percutaneous ablation techniques of breast cancer have a high rate of technical success, while technique efficacy remains suboptimal. Complication rates are relatively low.

KEY POINTS

• Imaging-guided ablation techniques for breast cancer are 96% technically successful. • Overall technique efficacy rate is 75% but largely inhomogeneous among studies. • Overall major and minor complication rates are low (6-8%).

Minimally invasive ablative techniques in the treatment of breast cancer: a systematic review and meta-analysis

PURPOSE

Breast-conserving surgery is effective for breast cancer treatment but is associated with morbidity in particular high re-excision rates. We performed a systematic review and meta-analysis to assess the current evidence for clinical outcomes with minimally invasive ablative techniques in the non-surgical treatment of breast cancer.

METHODS

A systematic search of the literature was performed using PubMed and Medline library databases to identify all studies published between 1994 and May 2016. Studies were considered eligible for inclusion if they evaluated the role of ablative techniques in the treatment of breast cancer and included ten patients or more. Studies that failed to fulfil the inclusion criteria were excluded.

RESULTS

We identified 63 studies including 1608 patients whose breast tumours were treated with radiofrequency (RFA), high intensity focussed ultrasound (HIFU), cryo-, laser or microwave ablation. Fifty studies reported on the number of patients with complete ablation as found on histopathology and the highest rate of complete ablation was achieved with RFA (87.1%, 491/564) and microwave ablation (83.2%, 89/107). Short-term complications were most often reported with microwave ablation (14.6%, 21/144). Recurrence was reported in 24 patients (4.2%, 24/570) and most often with laser ablation (10.7%, 11/103). The shortest treatment times were observed with RFA (15.6 ± 5.6 min) and the longest with HIFU (101.5 ± 46.6 min).

CONCLUSION

Minimally invasive ablative techniques are able to successfully induce coagulative necrosis in breast cancer with a low side effect profile. Adequately powered and prospectively conducted cohort trials are required to confirm complete pathological ablation in all patients.

Meta-analysis of radiofrequency ablation for treating the local recurrence of thyroid cancers

OBJECTIVES

Our aim was to evaluate the efficacy of ultrasound-guided radiofrequency ablation (RFA) for localized recurrent thyroid cancers.

METHODS

We did a systematic review and meta-analysis of the scientific literature by searching the PubMed, Embase, Web of Science,Scopus and the Cochrane Library up to November 26, 2015. We assessed the pooled standard mean difference (SMD) of nodule volume, largest diameter and serum thyroglobulin (Tg) level by comparing pre-RFA with post-RFA using fixed or random-effects model. The Newcastle-Ottawa Scale was used to evaluate the methodological quality of the included studies, risk of bias in the selective populations, comparability of groups and exposure.

RESULTS

We finally identified nine articles including 189 patients (male: 54 and female: 135) with 255 tumor lesions, who underwent ultrasound (US)-guided RFA beyond the mean 6 months of follow-up. The results showed that tumor volume (SWD: 0.77, 95 % CI: 0.57-0.97, I (2) = 25.9 %, p = 0.231), largest diameter (SWD: 1.56, 95 % CI: 0.94-2.17, I (2) = 82.6 %, p < 0.001) and Tg level (SWD: 0.52, 95 % CI: 0.30-0.73, I (2) = 0 %, p = 0.493) were decreased and no significant publication bias was detectable.

CONCLUSIONS

The pooled data indicated that the prognosis improved for patients with localized recurrent thyroid cancers and RFA is a promising treatment for these patients with infeasible surgery.

Meta-analysis of the concordance of histological grade of breast cancer between core needle biopsy and surgical excision specimen

BACKGROUND

With the increasing use of neoadjuvant chemotherapy and minimally invasive ablative therapy in breast cancer, pretreatment assessment of tumour grade on core needle biopsy (CNB) is increasingly needed. However, grading on CNB is possibly less accurate than grading based on the surgical excision specimen. A systematic review and meta-analysis of the literature was conducted to derive a reliable estimate of the agreement in tumour grading between CNB and subsequent surgical excision.

METHODS

Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) criteria, Embase, PubMed and the Cochrane Library were searched. Pooled proportions of agreement in grading between CNB and the excision specimen, Cohen's κ and percentages of overestimation and underestimation were calculated. Random-effects models were applied because of substantial heterogeneity, assessed by I² test. Determinants of the level of agreement in grading were explored with meta-regression.

RESULTS

Thirty-four articles were included in the systematic review (6029 patients) and 33 in the meta-analysis (4980 patients). Pooled agreement and κ were 71·1 (95 per cent c.i. 68·8 to 73·3) per cent and 0·54 (0·50 to 0·58) respectively. Underestimation and overestimation occurred in 19·1 (17·1 to 21·3) and 9·3 (7·7 to 11·4) per cent respectively. Meta-regression showed associations between agreement of histological type (positive association) and proportion of patients with oestrogen receptor-positive disease (negative association) and grade agreement.

CONCLUSION

Grading on CNB corresponds moderately with grading based on excision specimens, with underestimation in about one in five patients. Incorrect CNB tumour grading has limited clinical implications, as multiple factors influence decision-making for adjuvant systemic therapy.

Histopathology of breast cancer after magnetic resonance-guided high-intensity focused ultrasound and radiofrequency ablation

AIMS

Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation and radiofrequency ablation (RFA) are being researched as possible substitutes for surgery in breast cancer patients. The histopathological appearance of ablated tissue has not been studied in great detail. This study aimed to compare histopathological features of breast cancer after MR-HIFU ablation and RFA.

METHODS AND RESULTS

MR-HIFU ablation and RFA were performed in- and ex-vivo. Tumours in six mastectomy specimens were partially ablated with RFA or MR-HIFU. In-vivo MR-HIFU ablation was performed 3-6 days before excision; RFA was performed in the operation room. Tissue was fixed in formalin and processed to haematoxylin and eosin (H&E) and cytokeratin-8 (CK-8)-stained slides. Morphology and cell viability were assessed. Ex-vivo ablation resulted in clear morphological changes after RFA versus subtle differences after MR-HIFU. CK-8 staining was decreased or absent. H&E tended to underestimate the size of thermal damage. In-vivo MR-HIFU resulted in necrotic-like changes. Surprisingly, some ablated lesions were CK-8-positive. Histopathology after in-vivo RFA resembled ex-vivo RFA, with hyper-eosinophilic stroma and elongated nuclei. Lesion borders were sharp after MR-HIFU and indistinct after RFA.

CONCLUSION

Histopathological differences between MR-HIFU-ablated tissue and RF-ablated tissue were demonstrated. CK-8 was more reliable for cell viability assessment than H&E when used directly after ablation, while H&E was more reliable in ablated tissue left in situ for a few days. Our results contribute to improved understanding of histopathological features in breast cancer lesions treated with minimally invasive ablative techniques.

Surgical treatment of nonpalpable primary invasive and in situ breast cancer

Breast cancer is the most-common cancer among women worldwide, and over one-third of all cases diagnosed annually are nonpalpable at diagnosis. The increasingly widespread implementation of breast-screening programmes, combined with the use of advanced imaging modalities, such as magnetic resonance imaging (MRI), will further increase the numbers of patients diagnosed with this disease. The current standard management for nonpalpable breast cancer is localized surgical excision combined with axillary staging, using sentinel-lymph-node biopsy in the clinically and radiologically normal axilla. Wire-guided localization (WGL) during mammography is a method that was developed over 40 years ago to enable lesion localization preoperatively; this technique became the standard of care in the absence of a better alternative. Over the past 20 years, however, other technologies have been developed as alternatives to WGL in order to overcome the technical and outcome-related limitations of this technique. This Review discusses the techniques available for the surgical management of nonpalpable breast cancer; we describe their advantages and disadvantages, and highlight future directions for the development of new technologies.