Success of sentinel lymph node mapping after breast cancer ablation with focused microwave phased array thermotherapy

The Applications of High-Intensity Focused Ultrasound (HIFU) Ablative Therapy in the Treatment of Primary Breast Cancer: A Systematic Review

BACKGROUND

This study evaluates the role of high-intensity focused ultrasound (HIFU) ablative therapy in treating primary breast cancer.

METHODS

PubMed and Scopus databases were searched according to the PRISMA guidelines to identify studies from 2002 to November 2022. Eligible studies were selected based on criteria such as experimental study type, the use of HIFU therapy as a treatment for localised breast cancer with objective clinical evaluation, i.e., clinical, radiological, and pathological outcomes. Nine studies were included in this study.

RESULTS

Two randomised controlled trials and seven non-randomised clinical trials fulfilled the inclusion criteria. The percentage of patients who achieved complete (100%) coagulation necrosis varied from 17% to 100% across all studies. Eight of the nine studies followed the treat-and-resect protocol in which HIFU-ablated tumours were surgically resected for pathological evaluation. Most breast cancers were single, solitary, and palpable breast tumours. Haematoxylin and eosin stains used for histopathological evaluation showed evidence of coagulation necrosis. Radiological evaluation by MRI showed an absence of contrast enhancement in the HIFU-treated tumour and 1.5 to 2 cm of normal breast tissue, with a thin peripheral rim of enhancement indicative of coagulation necrosis. All studies did not report severe complications, i.e., haemorrhage and infection. Common complications related to HIFU ablation were local mammary oedema, pain, tenderness, and mild to moderate burns. Only one third-degree burn was reported. Generally, the cosmetic outcome was good. The five-year disease-free survival rate was 95%, as reported in two RCTs.

CONCLUSIONS

HIFU ablation can induce tumour coagulation necrosis in localised breast cancer, with a favourable safety profile and cosmetic outcome. However, there is variable evidence of complete coagulation necrosis in the HIFU-treated tumour. Histopathological evidence of coagulation necrosis has been inconsistent, and there is no reliable radiological modality to assess coagulation necrosis confidently. Further exploration is needed to establish the accurate ablation margin with a reliable radiological modality for treatment and follow-up. HIFU therapy is currently limited to single, palpable breast tumours. More extensive and randomised clinical trials are needed to evaluate HIFU therapy for breast cancer, especially where the tumour is left in situ.

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.

Thermal Boost Combined with Interstitial Brachytherapy in Early Breast Cancer Conserving Therapy—Initial Group Long-Term Clinical Results and Late Toxicity

(1) In breast-conserving therapy (BCT), adjuvant radiation, including tumor bed boost, is mandatory. Safely delivered thermal boost (TB) based on radio-sensitizing interstitial microwave hyperthermia (MWHT) preceding standard high-dose-rate (HDR) brachytherapy (BT) boost has the potential for local control (LC) improvement. The study is to report the long-term results regarding LC, disease-free survival (DFS), overall survival (OS), toxicity, and cosmetic outcome (CO) of HDR-BT boost ± MWHT for early breast cancer (BC) patients treated with BCT. (2) In the years 2006 and 2007, 57 diverse stages and risk (IA-IIIA) BC patients were treated with BCT ± adjuvant chemotherapy followed by 42.5–50.0 Gy whole breast irradiation (WBI) and 10 Gy HDR-BT boost. Overall, 25 patients (group A; 43.9%) had a BT boost, and 32 (group B; 56.1%) had an additional pre-BT single session of interstitial MWHT on a tumor bed. Long-term LC, DFS, OS, CO, and late toxicity were evaluated. (3) Median follow-up was 94.8 months (range 1.1–185.5). LC was 55/57, or 96.5% (1 LR in each group). DFS was 48/57, or 84.2% (4 failures in group A, 5 in B). OS was 46/57, or 80.7% (6 deaths in group A, 5 in B). CO was excellent in 60%, good in 36%, and satisfactory in 4% (A), and in 53.1%, 34.4%, and 9.4% (B), respectively. One poor outcome was noted (B). Late toxicity as tumor bed hardening occurred in 19/57, or 33.3% of patients (9 in A, 10 in B). In one patient, grade 2 telangiectasia occurred (group A). All differences were statistically insignificant. (4) HDR-BT boost ± TB was feasible, well-tolerated, and highly locally effective. LC, DFS, and OS were equally distributed between the groups. Pre-BT MWHT did not increase rare late toxicity.

Thermal Boost to Breast Tumor Bed—New Technique Description, Treatment Application and Example Clinical Results

(1) Current breast-conserving therapy for breast cancer consists of a combination of many consecutive treatment modalities. The most crucial goal of postoperative treatment is to eradicate potentially relapse-forming residual cancerous cells within the tumor bed. To achieve this, the HDR brachytherapy boost standardly added to external beam radiotherapy was enhanced with an initial thermal boost. This study presents an original thermal boost technique developed in the clinic. (2) A detailed point-by-point description of thermal boost application is presented. Data on proper patient selection, microwave thermal boost planning, and interstitial hyperthermia treatment delivery are supported by relevant figures and schemes. (3) Out of 1134 breast cancer patients who were administered HDR brachytherapy boost in the tumor bed, 262 were also pre-heated interstitially without unexpected complications. The results are supported by two example cases of hyperthermia planning and delivery. (4) Additional breast cancer interstitial thermal boost preceding HDR brachytherapy boost as a part of combined treatment in a unique postoperative setting was feasible, well-tolerated, completed in a reasonable amount of time, and reproducible. A commercially available interstitial hyperthermia system fit and worked well with standard interstitial brachytherapy equipment.

Precision Breast-Conserving Surgery With Microwave Ablation Guidance: A Pilot Single-Center, Prospective Cohort Study

Introduction

Negative margins in breast-conserving surgery (BCS) are essential for preventing recurrence. The aim of this study was to determine the use of preoperative microwave ablation (MWA) in the guidance of BCS for early-stage breast cancer and access whether MWA could influence the rates of positive resection margins.

Methods

From 2016 to 2018, 22 women with T1/T2 invasive breast cancer were enrolled for MWA prospectively in the guidance of BCS. US-guided MWA was performed under local anesthesia, followed by BCS and sentinel lymph node biopsy (SLNB) one week after ablation. Women who underwent palpation-guided BCS directly were included as control, and propensity score matching analysis was applied.

Results

MWA was performed in 22 patients. Of the 21 MWA cases with effect information, the mean tumor size in US was 20.9 ± 6.2 mm (6-37 mm). Compared with control group (BCS directly), a lower rate of positive/close margins was observed in MWA guidance group (P = 0.018), and MWA caused a higher rate of accurate surgery (the largest margin ≤ 3 cm and the smallest margin ≥ 1mm, P = 0.042). Of these 21 patients treated with MWA, 18 were candidates for SLNB. And sentinel lymph nodes were successfully identified in all cases, and no recurrence was found with a mean follow-up of 23 months.

Conclusion

For patients with T1/T2 breast cancer, the application of preoperative MWA could guide BCS accurately without impairing SLNB. Clinical trials with long-term results are required to validate MWA in the guidance for breast cancer excision.

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.

MRI-guided ablation of breast cancer: where do we stand today?

The treatment of patients with localized breast cancer has changed considerably over the past few decades. The next challenge is to use image-guided minimally invasive tumor ablation techniques. The fact that MRI is the most accurate imaging modality for visualization and delineation of breast tumor margins in three dimensions and provides MRI-based temperature mapping, makes it particularly applicable for monitoring during minimally invasive ablation techniques. The overall result of the studies performed on MRI-guided minimally invasive tumor ablation studies are varying, with reported total tumor ablation rates ranging between 20% and 100%. Strict selection of patients, consensus on the treatment zone margin and optimization of MR-imaging, should make MRI-guided breast cancer tumor ablation a useful tool in clinical practice.

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.

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.

Focused microwave thermotherapy for preoperative treatment of invasive breast cancer: a review of clinical studies

BACKGROUND

Preoperative focused microwave thermotherapy (FMT) is a promising method for targeted treatment of breast cancer cells. Results of four multi-institutional clinical studies of preoperative FMT for treating invasive carcinomas in the intact breast are reviewed.

METHODS

Externally applied wide-field adaptive phased-array FMT has been investigated both as a preoperative heat-alone ablation treatment and as a combination treatment with preoperative anthracycline-based chemotherapy for breast tumors ranging in ultrasound-measured size from 0.8 to 7.8 cm.

RESULTS

In phase I, eight of ten (80%) patients receiving a single low dose of FMT prior to receiving mastectomy had a partial tumor response quantified by either ultrasound measurements of tumor volume reduction or by pathologic cell kill. In phase II, the FMT thermal dose was increased to establish a threshold dose to induce 100% pathologic tumor cell kill for invasive carcinomas prior to breast-conserving surgery (BCS). In a randomized study for patients with early-stage invasive breast cancer, of those patients receiving preoperative FMT at ablative temperatures, 0 of 34 (0%) patients had positive tumor margins, whereas positive margins occurred in 4 of 41 (9.8%) of patients receiving BCS alone (P = 0.13). In a randomized study for patients with large tumors, based on ultrasound measurements the median tumor volume reduction was 88.4% (n = 14) for patients receiving FMT and neoadjuvant chemotherapy, compared with 58.8% (n = 10) reduction in the neoadjuvant chemotherapy-alone arm (P = 0.048).

CONCLUSIONS

Wide-field adaptive phased-array FMT can be safely administered in a preoperative setting, and data from randomized studies suggest both a reduction in positive tumor margins as a heat-alone treatment for early-stage breast cancer and a reduction in tumor volume when used in combination with anthracycline-based chemotherapy for patients with large breast cancer tumors. Larger randomized studies are required to verify these conclusions.

Image-guided focused ultrasound ablation of breast cancer: current status, challenges, and future directions

Image-guided focussed ultrasound (FUS) ablation is a non-invasive procedure that has been used for treatment of benign or malignant breast tumours. Image-guidance during ablation is achieved either by using real-time ultrasound (US) or magnetic resonance imaging (MRI). The past decade phase I studies have proven MRI-guided and US-guided FUS ablation of breast cancer to be technically feasible and safe. We provide an overview of studies assessing the efficacy of FUS for breast tumour ablation as measured by percentages of complete tumour necrosis. Successful ablation ranged from 20% to 100%, depending on FUS system type, imaging technique, ablation protocol, and patient selection. Specific issues related to FUS ablation of breast cancer, such as increased treatment time for larger tumours, size of ablation margins, methods used for margin assessment and residual tumour detection after FUS ablation, and impact of FUS ablation on sentinel node procedure are presented. Finally, potential future applications of FUS for breast cancer treatment such as FUS-induced anti-tumour immune response, FUS-mediated gene transfer, and enhanced drug delivery are discussed. Currently, breast-conserving surgery remains the gold standard for breast cancer treatment.

Minimally invasive ablative therapies for invasive breast carcinomas: an overview of current literature

BACKGROUND

Minimally invasive treatment may be an alternative to breast-conserving surgery.

METHODS

A structured PubMed, Embase, Cochrane, and Web of Science search was performed. Endpoints studied were feasibility, completeness of ablation, timing of the sentinel node biopsy (SNB), imaging modalities, and treatment-related complications.

RESULTS

A total of 24 articles were retrieved, and the level of evidence varied (2B-4). Mainly phase II studies with a treat-and-resect protocol were analyzed. Up to 100% completeness of ablation was reported for radiofrequency ablation (RFA), cryosurgery, and focused ultrasound (FUS). The oncologic results need further evaluation. Dynamic contrast enhanced MRI seems to be the best method for monitoring treatment response (77% sensitivity, 100% specificity). Ultrasound is suitable for guiding probes into the tumor. There is no consensus on the timing of the SNB.

CONCLUSIONS

All studies on minimally invasive ablative modalities published so far show that these techniques are feasible and safe. At this stage only T1 tumors should be ablated in a clinical trial setting; it is unclear which of the modalities is most suitable.

Breast focused ultrasound surgery with magnetic resonance guidance

This paper will review the experience and current applications of magnetic resonance-guided focused ultrasound surgery (MRgFUS) for treatment of breast tumors. Because of the efficient screening mammography programs, most of the breast cancers diagnosed today in the United States and European Union are in early stage and are treated with limited surgery. The MRgFUS may offer an alternative treatment option to conventional surgical lumpectomy with the advantage of being a noninvasive procedure and potentially achieving a better cosmetic outcome. Selection of appropriate patients is of paramount importance. Additional studies are needed to determine the effectiveness of the MRgFUS tumor ablation and define its role as a replacement for surgical lumpectomy.

Extracorporeal high intensity focused ultrasound treatment for patients with breast cancer

PURPOSE

To investigate the safety, efficacy and feasibility of using high-intensity focused ultrasound (HIFU) as a non-invasive treatment for patients with breast cancer.

PATIENTS AND METHODS

Twenty-two patients with breast cancer were enrolled into this non-randomized prospective trial. Disease TNM stage was classified as stage I in 4 patients, stage II(A) in 9 patients, stage II(B) in 8 patients, and stage IV in 1 patient. Tumor size ranged from 2 to 4.8 cm in diameter (mean 3.4 cm). All patients received chemotherapy, radiation and tamoxifen, following HIFU for the primary lesions. Outcome measures included radiological and pathologic assessment of the treated tumor, cosmesis, and local recurrence. A cumulative survival rate is calculated by using the Kaplan-Meier method.

RESULTS

No severe complications were encountered after HIFU. Post-operative imaging demonstrated positive response and regression of all treated lesions. Follow-up biopsy revealed coagulation necrosis of target tumor and subsequent replacement by fibroblastic tissue. After a median follow-up of 54.8 months, 1 patient died, 1 was lost to follow-up, and 20 were still alive. Two of 22 patients developed local recurrence. Five-year disease-free survival and recurrence-free survival were 95% and 89%, respectively. Cosmetic result was judged as good to excellent in 94% of patients.

CONCLUSIONS

HIFU treatment is safe, effective, and feasible for patients with breast cancer. But, large-scale, multiple-center clinical trials will be needed to determine the future role of this novel modality.

Quantitative target sizes for breast tumor detection prior to metastasis: a prerequisite to rational design of 4D scanners for breast screening

It is important to determine a breast cancer tumor target size for new screening equipment and molecular detection. Records of women aged 40-69 years diagnosed in 1988-1997 with a nonmetastasized, node-negative, or node-positive T1-stage breast cancer were abstracted from the Surveillance, Epidemiology, and End Results (SEER) public-use database. The linear, Gompertzian, lognormal, and power-exponential models of the effect of tumor size on breast cancer specific mortality were compared using corresponding transforms of size in multivariate Cox proportional hazard models. Criteria for comparison were the linearization of the size transforms and the Nagelkerke R2N index for the Cox models. Our results show that the assumption of a linear effect of tumor size was rejected by the linearity test (P=0.05). The Gompertzian, lognormal, and power-exponential transforms satisfied the test with P-values of 0.08, 0.29, and 0.14, respectively. The corresponding R2N were 0.08410, 0.08420, and 0.08414, respectively, showing a marginally best fit with the lognormal model, which was selected as a model for small tumors. The lognormal function with unadjusted crude death rates gave a lognormal-location parameter of 25 and shape parameter of 1.7, while the corresponding values in multivariate models were 18 and 2, respectively. The derivation of the lognormal model indicates tumor growth acceleration starting at 3 mm (unadjusted crude data) or 2 mm (multivariate model). The breast cancer tumor target size for screening equipment, whether by imaging or molecular detection, is therefore 2 mm.

Ablative Approaches to the Minimally Invasive Treatment of Breast Cancer

With the improvements in imaging techniques that have allowed the earlier detection of smaller breast cancers and the desire for improvements in cosmetic outcome, a number of minimally invasive techniques for the treatment of early stage breast cancers are being investigated. Ablative therapies, including laser ablation, focused ultrasound, microwave ablation, radiofrequency ablation, and cryoablation, have been described. All of these techniques have shown promise in the treatment of small cancers of the breast; however, additional research is needed to determine the efficacy of these techniques when they are used as the sole therapy and to determine the long-term local recurrence rates and survival associated with these treatment strategies.