Radiofrequency Ablation of Invasive Breast Carcinomas: A Phase II Trial

Percutaneous ultrasound-guided cryoablation for early-stage primary breast cancer: a follow-up study in Japan

BACKGROUND

Ultrasound-guided percutaneous cryoablation (PCA) for early-stage breast cancer (ESBC) can be performed under local anesthesia in an outpatient clinic. This study continues a pilot stage to examine local control, safety, patient quality of life (QoL), satisfaction and cosmetic outcomes of cryoablation for ESBC.

METHODS

PCA was performed under local anesthesia for patients with primary ESBC, followed by radiation and endocrine therapies. Oncologic outcomes were examined by imaging (mammography, ultrasound, MRI) at baseline and 1, 6, 12, 24, 36, and 60 months post-cryoablation. EQ-VAS, EQ-5D-5L, subjective satisfaction and Moiré topography were used to measure health-related QoL outcomes.

RESULTS

Eighteen patients, mean aged 59.0 ± 9.0 years, mean tumor size 9.8 ± 2.3 mm, ER + , PR + (17/18), HER2-, Ki67 < 20% (15/18), underwent PCA and were followed for a mean of 44.3 months. No serious adverse events were reported, and no patients had local recurrence or distant metastasis in the 5-year follow-up. Cosmetic outcomes, satisfaction level, and QoL all improved post-cryoablation. Five-year average reduction rates of the cryolesion long, short, and depth diameters, on US, were 61.3%, 42.3%, and 22.8%, respectively, compared to the 86.2% volume reduction rate on MRI. The correlation coefficient between MRI and US measurement criteria was highest for the long diameter. During follow-up, calcification of the treated area was observed in 13/18 cases.

CONCLUSION

Cryoablation for ESBC is an effective and safe procedure with excellent cosmetic outcomes and improved QoL. This study contributes to the growing evidence supporting cryoablation as a potential standard treatment for ESBC, given compliance to pre-defined patient selection criteria.

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.

Treatment of early-stage breast cancer with percutaneous thermal ablation, an open-label randomised phase 2 screening trial: rationale and design of the THERMAC trial

INTRODUCTION

Breast cancer is the most frequently diagnosed malignancy worldwide but almost half of the patients have an excellent prognosis with a 5-year survival rate of 98%-99%. These patients could potentially be treated with thermal ablation to avoid surgical excision, reduce treatment-related morbidity and increase patients' quality of life without jeopardising treatment effectiveness. Previous studies showed highest complete ablation rates for radiofrequency, microwave and cryoablation. However, due to heterogeneity among studies, it is unknown which of these three techniques should be selected for a phase 3 comparative study.

METHODS AND ANALYSIS

The aim of this phase 2 screening trial is to determine the efficacy rate of radiofrequency, microwave and cryoablation with the intention to select one treatment for further testing in a phase 3 trial. Additionally, exploratory data are obtained for the phase 3 trial. The design is a multicentre open-label randomised phase 2 screening trial. Patients with unifocal, invasive breast cancer with a maximum diameter of 2 cm without lymph node or distant metastases are included. Triple negative, Bloom-Richardson grade 3 tumours and patients with an indication for neoadjuvant chemotherapy will be excluded. Included patients will be allocated to receive one of the three thermal ablation techniques. Three months later surgical excision will be performed to determine the efficacy of thermal ablation. Treatment efficacy in terms of complete ablation rate will be assessed with CK 8/18 and H&E staining. Secondary outcomes include feasibility of the techniques in an outpatient setting, accuracy of MRI for complete ablation, patient satisfaction, adverse events, side effects, cosmetic outcome, system usability and immune response.

ETHICS AND DISSEMINATION

This study protocol was approved by Medical Research Ethics Committee of the Erasmus Medical Center, Rotterdam, the Netherlands. Study results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NL9205 (www.trialregister.nl); Pre-results.

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.

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.

A meta-analysis of clinical trials assessing the effect of radiofrequency ablation for breast cancer

Background

Radiofrequency ablation (RFA) is a minimally invasive thermal ablation technique. We conducted a meta-analysis based on eligible studies to assess the efficacy and safety of RFA for treating patients with breast cancer.

Methods

A literature search was conducted in PubMed, Embase, and Web of Science databases. Eligible studies were clinical trials that assessed RFA in patients with breast cancer. The outcomes included complete ablation rate, recurrence rate, excellent or good cosmetic rates, and complication rate. A random-effects or fixed-effects model was used to pool the estimate, according to the heterogeneity among the included studies.

Results

Fifteen studies, with a total of 404 patients, were included in this meta-analysis. Pooled results showed that 89% (95% confidence interval: 85%–93%) of patients achieved a complete ablation after RFA treatment and 96% of patients reported a good-to-excellent cosmetic result. Although the pooled result for recurrence rate was 0, several cases of relapse were observed at different follow-up times. No RFA-related complications were recorded, except for skin burn with an incidence of 4% (95% confidence interval: 1%–6%).

Conclusion

This meta-analysis showed that RFA can be a promising alternative option for treating breast cancer since it produces a higher complete ablation rate with a low complication rate. Further well-designed randomized controlled trials are needed to confirm the efficacy and safety of RFA for breast cancer.

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.

Current status of imaging-guided percutaneous ablation of breast cancer

OBJECTIVE

The purpose of this article is to briefly describe the various techniques used for percutaneous ablation of breast cancer, their preliminary results, and their limitations. The techniques include thermotherapy (radiofrequency ablation, laser irradiation, microwave irradiation, and insonation with high-intensity focused ultrasound waves), cryotherapy, and irreversible electroporation.

CONCLUSION

The techniques used for percutaneous ablation of breast cancer raise many questions and issues that must be addressed before percutaneous ablation can be adopted for the treatment of early breast cancer.

Radiofrequency ablation and breast cancer: a review

BACKGROUND

Radiofrequency ablation (RFA) use in breast cancer is a developing area of research. There have been a number of published studies over the last decade, which explores the feasibility of minimally invasive techniques in breast cancer treatment. In this review, we will discuss the most recent data on radiofrequency ablation and examine the current methods, outcomes, complications, and limitations of RFA in breast cancer therapy.

METHODS

Pub Med search for English Language articles on RFA in breast cancer.

RESULTS

More than 25 studies were reviewed and we searched for number of tumors, average size, electrode used, if they successfully ablated the tumor, when the tumor was then resected and if the patients experienced any complication from the ablation.

CONCLUSIONS

Radiofrequency ablation is an emerging minimally invasive therapy in small, localized breast cancer. Currently, no clinical trials have been published to directly compare RFA to the current standard of surgical resection. Ultimately, RFA will need clinical trials to evaluate oncologic outcomes involving long interval follow-up to determine survival, local control and disease progression before it becomes a reasonable alternative to surgical resection.

Percutaneous image-guided ablation of breast tumors: an overview

Percutaneous non-surgical image-guided ablation is emerging as an adjunct or alternative to surgery in the management of benign and malignant breast tumors. This review covers the current state of the literature regarding percutaneous image-guided ablation modalities, clinical factors regarding patient selection, and future directions for research.

Nonsurgical ablation of breast cancer: future options for small breast tumors

The surgical management of breast cancer has evolved significantly, facilitated by advancements in technology and imaging and improvements in adjuvant therapy. The changes in surgical management have been characterized by equal or improved outcomes with significantly less morbidity. The next step in this evolution is the minimally invasive or noninvasive ablation of breast cancers as an alternative to lumpectomy. In this article, the various modalities for nonsurgical breast cancer ablation and the clinical experience are reviewed, and some of the next steps necessary for their clinical implementation are outlined.

[Minimally invasive breast surgery]

Due to the development in medical science and industrial technology, minimally invasive procedures have appeared in the surgery of benign and malignant breast diseases. In general , such interventions result in significantly reduced breast and chest wall scars, shorter hospitalization and less pain, but they require specific, expensive devices, longer surgical time compared to open surgery. Furthermore, indications or oncological safety have not been established yet. It is quite likely, that minimally invasive surgical procedures with high-tech devices - similar to other surgical subspecialties -, will gradually become popular and it may form part of routine breast surgery even. Vacuum-assisted core biopsy with a therapeutic indication is suitable for the removal of benign fibroadenomas leaving behind an almost invisible scar, while endoscopically assisted skin-sparing and nipple-sparing mastectomy, axillary staging and reconstruction with latissimus dorsi muscle flap are all feasible through the same short axillary incision. Endoscopic techniques are also suitable for the diagnostics and treatment of intracapsular complications of implant-based breast reconstructions (intracapsular fluid, implant rupture, capsular contracture) and for the biopsy of intracapsular lesions with uncertain pathology. Perception of the role of radiofrequency ablation of breast tumors requires further hands-on experience, but it is likely that it can serve as a replacement of surgical removal in a portion of primary tumors in the future due to the development in functional imaging and anticancer drugs. With the reduction of the price of ductoscopes routine examination of the ductal branch system, guided microdochectomy and targeted surgical removal of terminal ducto-lobular units or a "sick lobe" as an anatomical unit may become feasible. The paper presents the experience of the authors and provides a literature review, for the first time in Hungarian language on the subject. Orv. Hetil., 2014, 155(5), 162-169.

Image and pathological changes after radiofrequency ablation of invasive breast cancer: a pilot study of nonsurgical therapy of early breast cancer

BACKGROUND

The surgical treatment of early breast cancer has proceeded to less invasive approaches with better cosmetic results. The current study was undertaken to evaluate the clinical and pathological findings after radiofrequency ablation (RFA) without resection for a longer period of time.

METHOD

A total of 14 patients with breast cancer were enrolled. All patients were diagnosed to have invasive ductal carcinoma, and the median breast tumor size was 12 mm (range, 6-20 mm). Six patients received RFA treatment followed by immediate resection and eight patients without resection. The patients without resection were evaluated by ultrasound, MRI, and the pathological findings of a core needle biopsy after RFA. The removed specimens were examined by hematoxylin-eosin (HE) staining and nicotinamide adenine dinucleotide (NADH) diaphorase staining. The median follow-up of the patients was 39.9 months.

RESULTS

NADH staining was necessary to diagnose complete tumor cell death in the tissue for 3 months after RFA. However, HE staining alone could confirm the effect without NADH staining more than 6 months after RFA. Post-RFA, MRI scans clearly demonstrated the area as a complete ablated lesion in all patients without resection. The ablated area detected by MRI or ultrasound became gradually smaller. All patients that underwent RFA with no resection were alive without relapse.

CONCLUSION

RFA therefore could be an effective alternative to partial mastectomy for early breast cancer. Further research will be necessary to establish the standardization of the indications, as well as the optimal techniques and post treatment evaluation modalities.

Ultrasound-guided radiofrequency ablation of early breast cancer in a resection specimen: lessons for further research

PURPOSE

To assess the feasibility and effectiveness of radiofrequency ablation (RFA) in breast cancer, using different histopathologic staining methods to evaluate tissue viability.

MATERIALS AND METHODS

In twenty patients with unifocal small (≤1, 5 cm) invasive ductal carcinoma, ultrasound-guided RFA was performed immediately after surgery. Cell viability was assessed using cytokeratin 8 (CK 8) and nicotinamide adenine dinucleotide diaphorase (NADHD) in addition to hematoxylin-eosin (HE).

RESULTS

At histopathological examination, ex vivo RFA resulted in complete cell death of the target lesion in 17/20 patients. In two cases viable ductal carcinoma in situ (DCIS) was found just outside the completely ablated lesion.

CONCLUSION

RFA of small invasive breast cancer seems to be a feasible treatment option. Both NADHD and CK 8 demonstrate a clear and comparable demarcation between viable and non-viable tissue. A high level of accuracy is required in proper positioning of the needle electrode and a "hot retraction" is mandatory.

Long-term outcome of breast cancer patients treated with radiofrequency ablation

BACKGROUND

Radiofrequency ablation (RFA) is considered to be the most promising non-surgical ablation technique for the treatment of small breast cancer. However, few data are available regarding long-term follow-up of patients treated with this modality.

METHODS

Since 2005, we have performed RFA and sentinel lymph node (SLN) biopsy in 19 cases. Axillary lymph node dissection (ALND) was performed in patients with positive SLNs. From 24 to 202 days after RFA, the ablated tumour tissue was excised by mammotome biopsy and examined histologically or immunohistochemically with H&E staining, nicotinamide adenine dinucleotide (NADH)-diaphorase staining, and single-stranded (ss) DNA staining. All cases were followed-up after breast radiation and systemic therapies.

RESULTS

Although complete response was histologically confirmed in only 8 cases, NADH-diaphorase and ssDNA staining did not demonstrate any viable tumour cells in the ablated lesions. At a mean follow-up of 60 months (follow-up range, 37-82 months), there were no cases of in-breast recurrence, although one patient died due to hepatic metastases. Cosmesis of the conserved breast was excellent or good in all of the cases, but a hard lump was persistent after RFA in half of the cases.

CONCLUSIONS

The long-term outcome of patients treated with RFA is encouraging with regard to cosmesis and local control. Because a persisted lump may cause patient discomfort, anxiety and fear, however, further studies are needed to establish the optimal technique. Moreover, a prospective study will be required to determine the equivalency in local recurrence rates between the RFA therapy and conventional breast-conserving treatment.

Image-guided tumor ablation: emerging technologies and future directions

As the trend continues toward the decreased invasiveness of medical procedures, image-guided percutaneous ablation has begun to supplant surgery for the local control of small tumors in the liver, kidney, and lung. New ablation technologies, and refinements of existing technologies, will enable treatment of larger and more complex tumors in these and other organs. At the same time, improvements in intraprocedural imaging promise to improve treatment accuracy and reduce complications. In this review, the latest advancements in clinical and experimental ablation technologies will be summarized, and new applications of image-guided tumor ablation will be discussed.

Analysis by MRI of residual tumor after radiofrequency ablation for early stage breast cancer

OBJECTIVE

The objective of our study was to evaluate the effectiveness of MRI in the detection of possible residual lesions after radiofrequency ablation (RFA) in the treatment of breast cancer.

SUBJECTS AND METHODS

We prospectively evaluated 14 patients who had undergone ultrasound-guided core biopsies diagnostic of invasive ductal carcinoma (IDC; range of diameters, 1.0-3.0 cm) and then ultrasound-guided percutaneous RFA with sentinel node biopsy as the primary treatment. Breast MRI was performed 1 week before RFA to evaluate tumor extension and again 3 weeks after RFA to verify the presence of possible residual lesions. Conventional surgical resection of the tumors was performed 1 week after RFA. The MRI findings were compared with histopathologic analyses to confirm the presence or absence of residual tumor.

RESULTS

There was no residual enhancement in seven lesions on the postablation breast MRI scans. These findings were confirmed by negative histopathologic findings in the surgical specimens. The MRI scans of five patients showed small areas of irregular enhancement that corresponded to residual lesions. In the two remaining patients, we observed enhancement of almost the entire lesion, indicating that RFA had failed.

CONCLUSION

Breast MRI is effective in detecting residual lesions after RFA in patients with IDC.

Radiofrequency thermoablation in locally advanced breast cancer

The authors report their experience of 8 cases of breast cancer in six patients, treated by radiofrequency thermoablation. Two patients had bilateral breast cancer infiltrating the skin. All patients, but one, were alive at two years follow-up. The age range was 54-75 years old (median, 71 years old). We observed complete regression in one patient, regression with residual scar in two patients and partial regression in the remaining three patients. The authors believe that radiofrequency, alone or associated with other treatments, is an easy and useful alternative for the management of breast cancer, in selected patient who cannot undergo surgery or refuse surgical treatment and other treatments.

Microwave ablation compared with radiofrequency ablation for breast tissue in an ex vivo bovine udder model

PURPOSE

To compare the effectiveness of microwave (MW) ablation with radiofrequency (RF) ablation for treating breast tissue in a nonperfused ex vivo model of healthy bovine udder tissue.

MATERIALS AND METHODS

MW ablations were performed at power outputs of 25W, 35W, and 45W using a 915-MHz frequency generator and a 2-cm active tip antenna. RF ablations were performed with a bipolar RF system with 2- and 3-cm active tip electrodes. Tissue temperatures were continuously monitored during ablation.

RESULTS

The mean short-axis diameters of the coagulation zones were 1.34 ± 0.14, 1.45 ± 0.13, and 1.74 ± 0.11 cm for MW ablation at outputs of 25W, 35W, and 45W. For RF ablation, the corresponding values were 1.16 ± 0.09 and 1.26 ± 0.14 cm with electrodes having 2- and 3-cm active tips, respectively. The mean coagulation volumes were 2.27 ± 0.65, 2.85 ± 0.72, and 4.45 ± 0.47 cm(3) for MW ablation at outputs of 25W, 35W, and 45W and 1.18 ± 0.30 and 2.29 ± 0.55 cm(3) got RF ablation with 2- and 3-cm electrodes, respectively. MW ablations at 35W and 45W achieved significantly longer short-axis diameters than RF ablations (P < 0.05). The highest tissue temperature was achieved with MW ablation at 45W (P < 0.05). On histological examination, the extent of the ablation zone in MW ablations was less affected by tissue heterogeneity than that in RF ablations.

CONCLUSION

MW ablation appears to be advantageous with respect to the volume of ablation and the shape of the margin of necrosis compared with RF ablation in an ex vivo bovine udder.

Ablative therapies of the breast

Minimally invasive ablative therapy techniques are being used in research protocols to treat benign and malignant tumors of the breast in select patient populations. These techniques offer the advantages of an outpatient setting, decreased pain, and improved cosmesis. These therapies, including radiofrequency ablation, cryotherapy, interstitial laser therapy, high-intensity focused ultrasonography, and focused microwave thermotherapy, are reviewed in this article.

Radiofrequency ablation of early breast cancer followed by delayed surgical resection--a promising alternative to breast-conserving surgery

To examine the radiofrequency ablation (RFA) reliability in early breast cancer, we performed RFA followed by delayed surgical resection on 41 patients with invasive or non-invasive breast carcinoma less than 2 cm. MRI scans were obtained before ablation and resection. Excised specimens were examined pathologically by haematoxylin-eosin and nicotinamide adenine dinucleotide-diaphorase staining. 40 patients completed 1 RFA session, which was sufficient to achieve complete tumour cell death. Overall complete ablation rate was 87.8% (36/41). There were no treatment-related complications other than that of a superficial burn in 1 case. After RFA, the tumour was no longer enhanced on MRI in 25/26 (96.2%) cases. Residual cancer, which was suspected on MRI in 1 case, was confirmed pathologically. MRI could be an applicable modality to evaluate therapeutic effect. RFA could be an alternate local treatment option to breast-conserving surgery for early breast cancer.

Minimally-invasive thermal ablation of early-stage breast cancer: a systemic review

BACKGROUND

Minimally-invasive thermal ablation techniques provide an effective approach for local destruction of solid tumor. A novel application is the use for treatment of early-stage breast carcinoma.

METHODS

A broad search was conducted in Pubmed, Embase and the Cochrane databases between January 1990 and December 2009. Clinical results of the relevant articles were collected and analyzed.

RESULTS

The analyzed studies were almost all feasibility or pilot studies using different energy sources, patients, tumor characteristics and ablation settings. They were conducted in research settings for the assessment of technical safety and feasibility, and none of those was used alone in clinical practice. Despite many methodological differences, complete tumor ablation could be achieved in 76-100% of breast cancer patients treated with radiofrequency ablation, 13-76% in laser ablation, 0-8% in microwave ablation, 36-83% in cryoablation, and 20-100% in high-intensity focused ultrasound ablation.

CONCLUSION

Minimally-invasive thermal ablation is a promising new tool for local destruction of small carcinomas of the breast. Large randomized control studies are required to assess the long-term advantages of minimally-invasive thermal ablation techniques compared to the current breast conserving therapies.

Radiofrequency ablation of breast cancer: a comparative study of two needle designs

BACKGROUND

Radiofrequency ablation (RFA) is an emerging minimally invasive technique for breast cancer treatment. There are two different needle designs. One is to deploy a series of arrays to allow an even distribution of heat within the tumor. A new design is a straight needle with continuous infusion of cold saline to prevent charring and ensure continuous heat delivery. We report the first comparative study using two different needles for ablation of breast cancer.

METHODS

Chinese patients with breast cancer less than 2 cm were prospectively recruited. Multifocal tumor was excluded. RFA was performed under general anesthesia following sentinel node biopsy. Sequential allocation was used. In the first group, tumor was ablated by using the LeVeen needle. Cool-tip needle was used in the subsequent group. The tumor was then resected. Tumor viability was assessed by nicotinamide adenine dinucleotide-diaphorase (NADH) staining. Complete ablation rate was compared. Evidence of thermal damage to the skin was also assessed.

RESULTS

Twenty patients were recruited. Mean tumor size was 14 mm. Complete ablation rate was the same (90% versus 89% for the Cool-tip and the LeVeen, respectively). Cool-tip has a shorter ablation time when compared with LeVeen (12 versus 28 min), and the Cool-tip needle was found to be easier to insert. There was no visible skin burn after RFA.

CONCLUSIONS

Cool-tip and LeVeen systems had the same efficacy in ablation of breast cancer, but Cool-tip was easier to insert and had a shorter ablation time.

Ultrasound-guided laser-induced thermal therapy for small palpable invasive breast carcinomas: a feasibility study

Background

The next step in breast-conserving surgery for small breast carcinomas could be local ablation. In this study, the feasibility of ultrasound-guided laser-induced thermal therapy (LITT) is evaluated.

Methods

Patients with large-core needle biopsy-proven invasive, palpable breast carcinoma (clinically ≤2 cm) underwent ultrasound-guided LITT, followed by surgical excision. Completeness of ablation was determined by both hematoxylin and eosin staining and nicotinamide adenosine diaphorase staining.

Results

Fourteen patients completed the treatment. The mean histological tumor size was 17 mm (range, 8–37 mm); 6 of 14 tumors were histologically larger than the clinical entry threshold of 2 cm. The power applied in all patients was 7 W, and the mean treatment time was 21.4 min (range, 15–30 min). In one patient, a skin burn occurred, and one patient had a localized pneumothorax that could be treated conservatively. In 7 (50%) of 14 patients, the tumor was completely ablated, as confirmed by nicotinamide adenosine diaphorase staining. In 11 cases, extensive in-situ carcinoma was present. In one case, the in-situ carcinoma was also completely ablated. A total of seven (88%) of eight tumors <2 cm in size were completely ablated versus one (17%) of six tumors that were ≥2 cm in size (P = .026).

Conclusions

Successful LITT of invasive breast cancer seems to be feasible when confined to small (<2 cm) nonlobular carcinomas without surrounding extensive in-situ component and angioinvasion. However, to implement LITT in a curative setting, improvements in imaging to more reliably preoperatively assess tumor size and monitoring of fiber tip placement and treatment affect are essential.

Radiofrequency thermal ablation of breast cancer local recurrence: a phase II clinical trial

BACKGROUND

The role of radiofrequency (RF) ablation to treat local recurrence of breast cancer is unknown.

METHODS

We conducted a two-stage phase II clinical trial. Eligible patients had a histologically confirmed noninflammatory and < or =3 cm ipsilateral breast tumor recurrence. The tumor site was identified by intraoperative sonography. A LeVeen needle electrode (RadioTherapeutics Corp, Mountain View, Calif) was inserted into a single site within the tumor and radiofrequency ablation was performed using a RF-2000 generator (RadioTherapeutics Corp). After completion of radiofrequency, a mastectomy was performed. Conventional staining and nicotinamide adenine dinucleotide-diaphorase (NADH-diaphorase) cell viability staining were performed.

RESULTS

During the first stage, procedures were uneventful. Conventional, cytokeratin, and NADH-diaphorase staining identified persistent viable tumor cells in the RF-ablated region in three patients. This phase II trial was stopped after completion of the first stage because of insufficient efficacy.

CONCLUSION

We demonstrate in this study that RF ablation is a potential technique to destroy local recurrence of breast tumors but the technique we tested in this phase II clinical trial had insufficient efficacy to recommend its use in routine.