Open-configuration MR-guided microwave thermocoagulation therapy for metastatic liver tumors from breast cancer

Survival outcomes and quality of life after percutaneous cryoablation for liver metastasis: A systematic review and meta-analysis

BACKGROUND

Liver metastasis is present in a wide range of malignancies, with colorectal cancer as the most common site. Several minimally invasive treatments have been suggested for managing hepatic metastases, and cryoablation is among them, yet not widely used. In this systematic review, we aimed to assess the effectiveness of percutaneous cryoablation in all types of liver metastases.

METHODS

A systematic search was performed in international databases, including PubMed, Scopus, Embase, and Web of Science, to find relevant studies reporting outcomes for percutaneous cryoablation in liver metastasis patients. In addition to baseline features such as mean age, gender, metastasis origin, and procedure details, procedure outcomes, including overall survival, local recurrence, quality of life (QoL), and complications, were extracted from the studies. Random-effect meta-analysis was performed to calculate the mean difference (MD) and 95% confidence interval for comparison of QoL.

RESULTS

We screened 2131 articles. Fifteen studies on 692 patients were included. Mean overall survival ranged from 14.5-29 months. The rate of local recurrence in the included studies ranged from 9.4% to 78%, and local control progression-free survival ranged from 1 to 31 months. The total QoL decreased one week after the cryoablation procedure (-3.08 [95% Confidence interval: -4.65, -1.50], p-value <0.01) but increased one month (5.69 [3.99, 7.39], p-value <0.01) and three months (3.75 [2.25, 5.24], p-value <0.01) after the procedure.

CONCLUSION

Cryoablation is an effective procedure for the treatment of liver metastases, especially in cases that are poor candidates for liver resection. It could significantly improve QoL with favorable local recurrence.

2450-MHz microwave ablation of liver metastases under 3.0 T wide-bore magnetic resonance guidance: a pilot study

To investigate the feasibility and effectiveness of 3.0 T wide-bore magnetic resonance (MR)-guided microwave ablation (MA) of liver metastases (LM). From October 2018 to May 2020, 39 patients with 63 LM were treated with 3.0 T wide-bore MR-guided 2450-MHz MA therapy. The procedure parameters, technical success, complications, biochemical index changes, local tumor response, local tumor progression (LTP), 12-month disease-free survival (DFS) and 12-month overall survival (OS) were recorded and analyzed. The mean tumor maximum diameter and total procedure time were 3.0 cm and 55.2 min, respectively. Technical success was 100%, but 5 cases (12.8%) had grade-1 complications. Alanine transaminase, aspartate transaminase and total bilirubin showed a slight transient increase on day 3 (P < 0.05) and returned to normal by day 30 (P > 0.05). The complete ablation rates for ≤ 2.5 and > 2.5 cm lesions were 100% and 92.5%, respectively. During the median follow-up of 12.0 months, the LTP rate was 4.8% (3/63), and the 12-month DFS and OS rates were 61.3% and 92.2%, respectively. 3.0 T wide-bore MR-guided MA for LM is a safe and effective approach, especially for small LM.

Development of a novel MR-conditional microwave needle for MR-guided interventional microwave ablation at 1.5T

PURPOSE

To develop an MR-conditional microwave needle that generates a spherical ablation zone and clear MRI visibility for MR-guided microwave ablation.

METHODS

An MR-conditional microwave needle consisting of zirconia tip and TA18 titanium alloy tube was investigated. The numerical model was created to optimize the needle's geometry and analyze its performance. A geometrically optimized needle was produced using non-magnetic materials based on the electromagnetics simulation results. The needle's mechanical properties were tested per the Chinese pharmaceutical industry standard YY0899-2013. The MRI visibility performance and ablation characteristics of the needle was tested both in vitro (phantom) and in vivo (rabbit) at 1.5T. The RF-induced heating was evaluated in ex vivo porcine liver.

RESULTS

The needle's mechanical properties met the specified requirements. The needle susceptibility artifact was clearly visible both in vitro and in vivo. The needle artifact diameter (A) was small in in vivo (A_shaft: 4.96 ± 0.18 mm for T1W-FLASH, 3.13 ± 0.05 mm for T2-weighted fast spin-echo (T2W-FSE); A_tip: 2.31 ± 0.09 mm for T1W-FLASH, 2.29 ± 0.08 mm for T2W-FSE; tip location error [TLE]_: -0.94 ± 0.07 mm for T1W-FLASH, -1.10 ± 0.09 mm for T2W-FSE). Ablation zones generated by the needle were nearly spherical with an elliptical aspect ratio ranging from 0.79 to 0.90 at 30 W, 50 W for 3, 5, 10 min duration ex vivo ablations and 0.86 at 30 W for 10 min duration in vivo ablations.

CONCLUSION

The designed MR-conditional microwave needle offers excellent mechanical properties, reliable MRI visibility, insignificant RF-induced heating, and a sufficiently spherical ablation zone. Further clinical development of MR-guided microwave ablation appears warranted.

CalliSpheres drug-eluting beads transarterial-chemoembolization in the treatment of liver metastases from breast cancer: Initial experience in 14 patients

Breast cancer patients with liver metastases are associated with high mortality. However, no standardized treatment approach is available for these patients who have undergone chemotherapy and hormonal therapy. We aimed to assess the clinical outcomes of patients with breast cancer liver metastases (BCLM) who underwent drug-eluting beads used for transarterial-chemoembolization (DEB-TACE).We retrospectively enrolled 14 patients with 39 lesions who underwent DEB-TACE for liver metastases following mastectomy for primary breast cancer. The incidence of complications, overall survival (OS), and local tumor progression-free survival (PFS) were assessed.A total of 14 patients with 39 liver metastases were treated with DEB-TACE from July 2017 to July 2020. The objective response rates (ORR) and disease control rates (DCR) were 71.4% and 92.8% at the 3-month period and 50% and 71.4% at the 6-month period, respectively. During the follow-up period the local tumor PFS was 8.0 months. The median OS was 20.0 months (range, 8-40 months) and the 1-, 2-year OS rates were 84.4% and 47.4%, respectively. No severe complications caused by this technique were detected.DEB-TACE for BCLM was characterized as a low trauma technique, with a limited number of complications. The results indicated that this method was safe and effective for patients with BCLM and could be widely adopted as a palliative treatment in clinical practice.

Interventional radiology in breast cancer

Molecular profiling of metastatic disease may greatly influence the systemic therapy recommended by oncologists and chosen by patients, allowing treatment to be more targeted. Comprehensive care of patients with advanced breast cancer now includes percutaneous image-guided biopsy if this has the potential to influence systemic treatment [1]. Interventional radiologists can contribute significantly to the care of patients affected by breast cancer, in diagnostic and supportive procedures and importantly also in treatment. Interventional radiologists carry out image guided percutaneous biopsies not only of the primary tumour but also of metastases. They insert percutaneous ports and tunnelled central venous catheters. They ablate painful bone metastases, and can treat or prevent pathological fractures. Most importantly they can ablate liver metastases in patients with limited or oligometastatic disease. The inhomogeneity and variety of cell populations in metastatic tumours from breast cancer, which is an important consideration in systemic therapy, is not an important consideration in the treatment of metastatic tumours using percutaneous ablative techniques, which are the major focus of this article. The treatment of primary tumours in the breast is also being explored, but is considered in its infancy at this stage.

1.0 T open-configuration magnetic resonance-guided microwave ablation of pig livers in real time

The current fastest frame rate of each single image slice in MR-guided ablation is 1.3 seconds, which means delayed imaging for human at an average reaction time: 0.33 seconds. The delayed imaging greatly limits the accuracy of puncture and ablation, and results in puncture injury or incomplete ablation. To overcome delayed imaging and obtain real-time imaging, the study was performed using a 1.0-T whole-body open configuration MR scanner in the livers of 10 Wuzhishan pigs. A respiratory-triggered liver matrix array was explored to guide and monitor microwave ablation in real-time. We successfully performed the entire ablation procedure under MR real-time guidance at 0.202 s, the fastest frame rate for each single image slice. The puncture time ranged from 23 min to 3 min. For the pigs, the mean puncture time was shorted to 4.75 minutes and the mean ablation time was 11.25 minutes at power 70 W. The mean length and widths were 4.62 ± 0.24 cm and 2.64 ± 0.13 cm, respectively. No complications or ablation related deaths during or after ablation were observed. In the current study, MR is able to guide microwave ablation like ultrasound in real-time guidance showing great potential for the treatment of liver tumors.

Perspectives of breast cancer thermotherapies

In this article, the use of different types of thermotherapies to treat breast cancer is reviewed. While hyperthermia is most commonly used as an adjuvant in combination with radiotherapy, chemotherapy, targeted therapy or cryotherapy to enhance the therapeutic effect of these therapies, thermoablation is usually carried out alone to eradicate small breast tumors. A recently developed thermotherapy, called magnetic hyperthermia, which involves localized heating of nanoparticles under the application of an alternating magnetic field, is also presented. The advantages and drawbacks of these different thermotherapies are highlighted.

A 3-D mathematical model to identify organ-specific risks in rats during thermal stress

Early prediction of the adverse outcomes associated with heat stress is critical for effective management and mitigation of injury, which may sometimes lead to extreme undesirable clinical conditions, such as multiorgan dysfunction syndrome and death. Here, we developed a computational model to predict the spatiotemporal temperature distribution in a rat exposed to heat stress in an attempt to understand the correlation between heat load and differential organ dysfunction. The model includes a three-dimensional representation of the rat anatomy obtained from medical imaging and incorporates the key mechanisms of heat transfer during thermoregulation. We formulated a novel approach to estimate blood temperature by accounting for blood mixing from the different organs and to estimate the effects of the circadian rhythm in body temperature by considering day-night variations in metabolic heat generation and blood perfusion. We validated the model using in vivo core temperature measurements in control and heat-stressed rats and other published experimental data. The model predictions were within 1 SD of the measured data. The liver demonstrated the greatest susceptibility to heat stress, with the maximum temperature reaching 2°C higher than the measured core temperature and 95% of its volume exceeding the targeted experimental core temperature. Other organs also attained temperatures greater than the core temperature, illustrating the need to monitor multiple organs during heat stress. The model facilitates the identification of organ-specific risks during heat stress and has the potential to aid in the development of improved clinical strategies for thermal-injury prevention and management.

CT-guided percutaneous microwave ablation of liver metastases from nasopharyngeal carcinoma

PURPOSE

To access efficacy of percutaneous microwave ablation (MWA) of liver metastases from nasopharyngeal carcinoma (NPC).

MATERIALS AND METHODS

From March 2007 to June 2012, 18 consecutive patients with NPC and liver metastases (15 men and three women; average age, 45.7 y; age range, 31-61 y) received computed tomography (CT)-guided percutaneous MWA treatment. A total of 27 ablations were performed involving 24 liver metastatic lesions in 18 patients with NPC. Average patient follow-up after ablation was 22.4 months (range, 2-52 mo). The average number of liver metastases per patient was 1.3 (range, 1-4 lesions), with lesion diameters ranging from 1.9 cm to 4.2 cm. Evaluation was then performed to assess percentage of complete necrosis, local tumor progression, and safety.

RESULTS

Technical success was achieved in all 27 MWA procedures performed. During follow-up, new metastatic lesions developed in four of 18 patients. Of these, two were liver metastases, and were successfully treated with repeat WMA. Only two major complications were observed: pneumothorax in a patient with an ablation pathway involving the thorax and postprocedural pain in two other patients. A median overall survival time of 41.4 months was observed (range, 2-50 mo); three of 18 patients died during follow-up.

CONCLUSIONS

CT-guided MWA is safe and offers an effective treatment alternative for local tumor control in selected patients with liver metastases from NPC.

Percutaneous cryoablation of liver metastases from breast cancer: initial experience in 17 patients

AIM

To assess the feasibility, safety, and effectiveness of percutaneous cryoablation for the treatment of liver metastases from breast cancer.

MATERIALS AND METHODS

This study included 39 liver metastases in 17 female breast cancer patients who underwent computed tomography (CT)-guided percutaneous cryoablation. The mean age of the cohort was 55 years (range 30-66 years). The tumour response was evaluated by CT performed before treatment, 1 month after treatment, and every 3 months thereafter. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30) was used to assess the patients' quality of life before, 1 week, 1 month, and 3 months after cryoablation. The primary endpoints were technique effectiveness, quality of life, and complications.

RESULTS

The technical success rate was 92% with no major complication reported. At the 1-month follow-up, the primary technique effectiveness was 87.1% (34 of 39 tumours). At the 3-months follow-up, local tumour progression was observed in six of 39 lesions (15.4%). The 1-year survival from the time of cryoablation was 70.6%. The quality of life symptoms and functioning scales were preserved in patients alive at 3 months after cryoablation. The global quality of life, mean value of "pain" and "fatigue" between 3 months after cryoablation and prior to treatment showed statistically significant differences, but no clinical significance.

CONCLUSIONS

Cryoablation is a safe and effective ablative therapy, providing a high rate of local tumour control in breast cancer liver metastases.

Thermal ablation therapies in patients with breast cancer liver metastases: a review

BACKGROUND

The liver is involved in about half of patients with metastatic breast cancer. Unfortunately systemic chemotherapy as the treatment of choice is limited. Due to multifocality and/or insufficient remnant liver volume, the majority of liver metastases are also unresectable. Currently, thermal ablations are used in these patients with acceptable impact.

METHODS

We reviewed studies on radiofrequency ablation (RFA), laser-induced thermotherapy (LITT) and microwave ablation (MWA) regarding local tumour response, progression and survival indexes in patients with breast cancer liver metastases (BCLM).

RESULTS

The reviewed literature showed positive response rates of 63 % to 97 % in RF-ablated lesions, 98.2 % in LITT-treated lesions and 34.5-62.5 % in MW-ablated lesions. Median survival was 10.9-60 months using RFA, 51-54 months after LITT and 41.8 months using MWA. Five-year survival rates were 27-30 %, 35 % and 29 %, respectively. Local tumour progression ranged from 13.5 % to 58 % using RFA, 2.9 % with LITT and 9.6 % with MWA.

CONCLUSION

The reviewed literature demonstrated that ablation therapies either as single therapy or combined with other locoregional therapies are a good alternative as an adjunction to resection in patients with resectable lesions or with positive response using chemotherapy. However, multicentre randomised studies should be conducted to obtain further evidence of the benefits of these treatments in patients with BCLM.

The role of surgery in metastatic breast cancer

Some of the patients who present with breast cancer already have distant metastatic disease. According to recent literature, these patients may benefit from resection of the breast tumour. One explanation for the effect of this resection is that reducing the tumour load influences metastatic growth. Results of future randomised controlled trials should indicate whether surgery of the breast tumour truly improves survival. Selected patients could even benefit from metastasectomy of liver and lung metastases; survival seems to improve and these procedures seldom lead to major complications. When metastasectomy is not possible, minimally invasive techniques can be used in selected patients for the treatment of breast cancer liver metastases, radiofrequency ablation (RFA) being discussed most in the literature. Patients with locally advanced breast cancer are treated multidisciplinarily and with curative intent. Part of the treatment is surgery to reduce tumour load. Regarding treatment of the axilla, in a clinically negative axilla sentinel node biopsy is advised before neoadjuvant treatment; an axillary lymph node dissection is not warranted. In local recurrence, surgery is the primary treatment. Axillary staging can be done in patients with a previous negative sentinel node biopsy. Regional recurrence after breast-conserving surgery or mastectomy is treated with surgery followed by radiotherapy.

MRI-guided musculoskeletal soft tissue interventions

This article highlights some of current state-of-the-art applications of interventional magnetic resonance imaging (MRI) technology pertaining to the musculoskeletal soft tissues. The rationale for the use of these techniques is to provide modes of minimally invasive diagnosis and/or therapy for a subset of patients whose lesions are not approachable by the traditional modes of interventional radiology and to introduce methods to mark subtle and infiltrative lesions to improve the outcomes of subsequent surgery or radiation therapy. These techniques build on the inherent attributes of MRI, particularly the high soft tissue contrast that made MRI the current mainstay diagnostic modality to identify and characterize musculoskeletal soft tissue lesions. The application of MRI technology to the musculoskeletal system, particularly for lesions related to the appendicular skeleton, does not typically suffer from the complexity related to involuntary organ motion. In addition, MRI-compatible versions of most of the needed instruments and devices for these interventions are currently available on commercial basis. Although musculoskeletal applications were not adopted early during the development of interventional MRI technology, we are likely to observe an increasing use of this technology for musculoskeletal soft tissue applications in the future.

Interventional navigation systems for treatment of unresectable liver tumor

Most patients with liver tumors are not candidates for surgical resection. A number of local treatment methods for unresectable liver tumors have recently received considerable interests. The major task of these procedures is accurate needle placement with the aim of complete tumor removal and minimal damage to surrounding normal liver parenchyma. In this article, we review the current status of interventional navigation system (INS) for treatment of unresectable liver tumors in terms of overall workflow, tracking systems, and research development. The conceptual design of INS consists of pre-operative and intra-operative modules. The tracking system falls into three types: optical, electromagnetic, and MR gradient based. The current INS, according to their image modalities, can be classified into four categories: MRI based, CT based, U/S based, and multimodalities based. The article also discusses the future research direction for enhanced performance of INS with real time imaging, high accuracy, high resolution, and friendly user-interface.

Breast cancer liver metastases: US-guided percutaneous radiofrequency ablation--intermediate and long-term survival rates

PURPOSE

To retrospectively assess the local control and intermediate- and long-term survival of patients with liver metastases from breast cancer who have undergone percutaneous ultrasonography (US)-guided radiofrequency (RF) ablation.

MATERIALS AND METHODS

This study was approved by the hospital ethics committee, and all patients provided written informed consent. RF ablation was used to treat 87 breast cancer liver metastases (mean diameter, 2.5 cm) in 52 female patients (median age, 55 years). Inclusion criteria were as follows: fewer than five tumors, maximum tumor diameter of 5 cm or smaller, and disease either confined to the liver or stable with medical therapy. Forty-five (90%) of 50 patients had previously undergone chemotherapy, hormonal therapy, or both, and had no response or an incomplete response to the treatment. Contrast material-enhanced computed tomography and US were performed to evaluate complications and technical success and to assess for local tumor progression during follow-up. The Kaplan-Meier method was used to assess survival, and results were compared between groups with a log-rank test. Cox regression analysis was used to assess independent prognostic factors that affected survival.

RESULTS

Complete tumor necrosis was achieved in 97% of tumors. Two (4%) minor complications occurred. Median time to follow-up from diagnosis of liver metastasis and from RF ablation was 37.2 and 19.1 months, respectively. Local tumor progression occurred in 25% of patients. New intrahepatic metastases developed in 53% of patients. From the time of first RF ablation, overall median survival time and 5-year survival rate were 29.9 months and 27%, respectively. From the time the first liver metastasis was diagnosed, overall median survival time was 42 months, and the 5-year survival rate was 32%. Patients with tumors 2.5 cm in diameter or larger had a worse prognosis (hazard ratio, 2.1) than did patients with tumors smaller than 2.5 cm in diameter.

CONCLUSION

Survival rates in selected patients with breast cancer liver metastases treated with RF ablation are comparable to those reported in the literature that were achieved with surgery or laser ablation.

Current status of liver tumor ablation devices

The liver is a common site of disease for both primary and metastatic cancer. Since most patients have a disease that is not amenable to surgical resection, tumor ablation modalities are increasingly being used for treatment of liver cancer. This review describes the current status of ablative technologies used as alternatives for resection, clinical experience with these technologies, currently available devices and design rules for the development of new devices and the improvement of existing ones. It focuses on probe design for radiofrequency ablation, microwave ablation and cryoablation, and compares the advantages and disadvantages of each ablation modality.

MR-guided microwave ablation for malignancies

Since we first successfully performed magnetic resonance (MR)-guided microwave coagulation therapy for liver tumors in January 2000, we have developed new MR-compatible instruments, laparoscopy and thoracoscopy, which have enabled us to approach liver tumors located just below the diaphragm and in contact with other organs. We have customized software for an MR gradient-based tracking system for the easy detection of the location and orientation of treatment area and for the real-time display of MR temperature maps with a scale bar. Navigation software was customized to enable real-time image navigation. The reformatted images in the two perpendicular planes complemented the limitations of real-time MR imaging. Evaluation software, "FootPrint," was useful for distinguishing treated areas from untreated areas and improved the evaluation of treatment accuracy. These newly developed MR-guided systems that utilize microwave have played important roles in more accurate, safer, and easier treatment for liver tumors. We have treated 184 patients using these new techniques without major complications.

An Easy-to-Use Microwave Hyperthermia System Combined with Spatially Resolved MR Temperature Maps: Phantom and Animal Studies

BACKGROUND

Hyperthermia has been used in multimodal cancer treatments, and in randomized, controlled studies, hyperthermia is an effective cancer therapy. For clinical accuracy and safety, however, temperature monitoring during treatment is essential. We aimed to develop a convenient microwave hyperthermia system combined with spatially resolved real-time temperature monitoring to improve its efficacy and safety.

MATERIALS AND METHODS

Using an MR-compatible irradiation-type microwave applicator, agar phantoms, thigh muscles of rabbit, and subcutaneous VX2 tumors of rabbit were heated in combination with noninvasive MR temperature maps. For MR temperature calculation, a proton resonance frequency method was used. After determination of temperature coefficients and evaluation of the precision in MR thermometry, distribution of microwave heating over time was examined for each substance.

RESULTS

The temperature coefficients of phantoms, rabbit muscles, and VX2 tumors were -0.00977, -0.00976, and -0.01027 ppm/ degrees C, respectively. The 95% limits of agreement of MR and fluoroptic thermometry in the three subjects were +0.318/-0.339 degrees C, +0.693/-0.661 degrees C, and +0.564/-0.526 degrees C, respectively. Concerning VX2 tumor, the average tumor temperature was 42.60 +/- 0.14 degrees C and the surface of skin was 43.27 +/- 0.45 degrees C in the 60-min experimental period.

CONCLUSIONS

With this easy-to-use microwave hyperthermia system, effective hyperthermia was accomplished in phantoms and living animals in combination with MR temperature maps.

Magnetic resonance-guided percutaneous microwave coagulation therapy for liver metastases of breast cancer in a case

Real-time magnetic resonance (MR) imaging enables the application of percutaneous microwave coagulation for high-risk patients with metastatic liver tumours. The tumours, local vessels and bile ducts can be observed clearly in three-dimensional sections and a sufficient surgical margin can be confirmed on the MR image even during the coagulation procedure. MR-guided percutaneous microwave coagulation therapy is effective for treatment of not only primary liver tumours but also metastatic breast cancers in the liver, which are not diffuse but discrete, and difficult to treat with only chemo-and endocrine therapy. We report a 44-year-old Japanese woman who underwent modified radical mastectomy for right breast cancer (T1c N0 M0 Stage I). Three years after the operation, she developed two metastatic liver tumours and was treated by MR-guided percutaneous microwave coagulation, achieving a complete response (CR) without any recurrence for 15 months as of the present. The most beneficial aspect of MR-guided percutaneous microwave coagulation is its safety. It is only minimally invasive and can be repeated. This therapy, therefore promises to prolong the disease free period. Additional clinical trials will be valuable to delineate the effectiveness and safety of MR-guided percutaneous microwave coagulation therapy for controlling the liver metastases of breast cancer.

Magnetic resonance guidance of thermal ablation

The aim of this study is to describe all aspects of the process of using MR imaging to control thermal ablation procedures and the strengths and weaknesses of the individual thermal ablation modalities in relation to their use in the MR environment. Magnetic resonance thermal sequences, MR scanner configurations, and the different thermal ablation modalities are discussed in the context of how they are commonly used in MR scanners to provide optimal image guidance of therapy. The outcomes of completed research on some of the applications of thermal tissue ablation using MR guidance are described to indicate how these processes may impact patient treatment. At the end of this review, the reader should have an understanding of how MR guidance of thermal ablation may be carried out, in what areas it is currently most used, and were it may develop in the near future.