Current oncologic applications of radiofrequency ablation therapies

Tissue Ablation: Applications and Perspectives

Tissue ablation techniques have emerged as a critical component of modern medical practice and biomedical research, offering versatile solutions for treating various diseases and disorders. Percutaneous ablation is minimally invasive and offers numerous advantages over traditional surgery, such as shorter recovery times, reduced hospital stays, and decreased healthcare costs. Intra-procedural imaging during ablation also allows precise visualization of the treated tissue while minimizing injury to the surrounding normal tissues, reducing the risk of complications. Here, the mechanisms of tissue ablation and innovative energy delivery systems are explored, highlighting recent advancements that have reshaped the landscape of clinical practice. Current clinical challenges related to tissue ablation are also discussed, underlining unmet clinical needs for more advanced material-based approaches to improve the delivery of energy and pharmacology-based therapeutics.

Minimally invasive treatment of early, good prognosis breast cancer-is this feasible?

Breast cancer screening programmes frequently detect early, good prognosis breast cancers with significant treatment burden for patients, and associated health-cost implications. Emerging evidence suggests a role for minimally invasive techniques in the management of these patients enabling many women to avoid surgical intervention. Minimally invasive techniques include vacuum-assisted excision, cryoablation, and radiofrequency ablation. We review published evidence in relation to the risks and benefits of each technique and discuss ongoing trials. Data to date are promising, and we predict a trend towards minimally invasive treatment for early, good-prognosis breast cancer as technical skills, suitability criteria, and follow-up protocols are established.

Peripheral T-cell subsets in radiofrequency ablation for tumors from different origins

BACKGROUNDS

Radiofrequency ablation (RFA) is known to destroy tumoral tissue and activate immune cells. This study aimed to investigate the impact of RFA on peripheral T-cell responses and its relationship with tumor origin and hepatitis status.

METHODS

A retrospective analysis was conducted on 62 patients with various types of tumors, including hepatocellular carcinoma, colorectal cancer, lung cancer, breast cancer, and others, who underwent RFA treatment between June 2017 and December 2018. Blood samples were collected before and one day after RFA treatment. The peripheral T-cell subsets were measured by flow cytometry, and their changes were analyzed.

RESULTS

The study found a decrease in the CD4+CD8-and CD4-CD8+ T-cell subsets after RFA, but no significant changes were observed in the populations of CD4+CD8+ and the CD4+CD8-/CD4-CD8+ ratio. Furthermore, no significant differences were observed in peripheral T-cell subsets concerning tumor type or hepatitis status.

CONCLUSIONS

The study suggests that RFA treatment may have a short-term impact on peripheral T-cell responses, characterized by a decrease in certain T-cell subsets. However, these changes do not seem to be related to the tumor type or hepatitis status of the patients.

Cryoablation for the treatment of breast cancer: immunological implications and future perspectives. Utopia or reality?

Cryoablation is a minimally invasive technique currently employed in breast cancer care, that uses freeze and thaw cycles to treat benign breast lesions, small breast cancers or focal sites of metastatic disease in patients not eligible for surgery. The final goal of this procedure is to destroy breast cancer cells using extreme cold. In addition, several studies have shown that this technique seems to have an enhancing effect on the immune response, especially by increasing the expression of tumor neoantigens specific to tumor cells, which are then attacked and destroyed. Exploiting this effect, cryoablation in combination with immunotherapy could be the key to treating early-stage breast cancers or patients who are unsuitable for surgery. According to some recent studies, there are other potential tools that could be used to enhance the therapeutic effect of cryoablation, such as FE3O4 nanoparticles or the manipulation of aquaporin expression. The aim of this narrative review is to summarize the current evidence regarding the use, indications, advantages and disadvantages of cryoablation in the treatment of breast cancer.

Advances and Challenges in Interventional Immuno-Oncology Locoregional Therapies

Interventional immuno-oncology is making strides in locoregional therapies to address complex tumor microenvironments. Long-standing interventional radiology cancer therapies, such as tumor ablation and embolization, are being recharacterized in the context of immunotherapy. Intratumoral injections, such as those of genetically engineered or unaltered viruses, and the delivery of immune cells, antibodies, proteins, or cytokines into targeted tumors, along with advancements in delivery techniques, have produced promising results in preliminary studies, indicating their antitumor effectiveness. Emerging strategies using DNA scaffolding, polysaccharides, glycan, chitosan, and natural products are also showing promise in targeted cancer therapy. The future of interventional immuno-oncology lies in personalized immunotherapies that capitalize on individual immune profiles and tumor characteristics, along with the exploration of combination therapies. This study will review various interventional immuno-oncology strategies and emerging technologies to enhance delivery of therapeutics and response to immunotherapy.

Is endoscopic radiofrequency ablation plus stent placement superior to stent placement alone for the treatment of malignant biliary obstruction? A systematic review and meta-analysis

OBJECTIVE

Malignant biliary obstruction (MBO) is a rare disease with a poor prognosis. Recent studies have shown that endoscopic radiofrequency ablation (ERFA) may improve survival. We conducted a systematic review and meta-analysis of the efficacy of ERFA in combination with biliary stent placement for the treatment of MBO.

METHODS

The study was registered in INPLASY (number 202340096). The PubMed, Cochrane Library, Web of Science, and Embase databases were searched from inception to April 2023. We selected studies comparing the efficacy of ERFA plus stent placement with stent placement alone. The primary outcomes were pooled hazard ratios (HRs) for overall survival and stent patency; the secondary outcomes were the odds ratios (ORs) for adverse events.

RESULTS

Eleven studies (four randomized controlled trials and seven observational studies) were included in the meta-analysis. Pooled analysis showed a difference in survival time between the two groups (HR 0.65, 95% confidence interval [CI] 0.58-0.73, I2 = 40%). However, there were no differences in the duration of stent patency or the incidence of adverse events (HR 1.04, 95% CI 0.84-1.29, I2 = 46%; OR 1.41, 95% CI 1.02-1.96, I2 = 29%).

CONCLUSIONS

ERFA has a significant survival benefit for MBO, but does not increase the risk of adverse events.

Feasibility of the chick chorioallantoic membrane model for preclinical studies on tumor radiofrequency ablation

BACKGROUND

We evaluated the feasibility of a chick chorioallantoic membrane (CAM) tumor model for preclinical research on tumor radiofrequency ablation (RFA).

METHODS

Fertilized chicken eggs were incubated and divided into five cohorts: RFA for 30 s (n = 5), RFA for 60 s (n = 5), RFA for 120 s (n = 4), sham (n = 8), and controls (n = 6). Xenografting using pancreatic neuroendocrine tumor cells of the BON-1 cell line was performed on embryonic day (ED) 8. The RFA was performed on ED 12. Survival, stereomicroscopic observations, and histological observations using hematoxylin-eosin (H&E) and Ki67 staining were evaluated.

RESULTS

The survival rates in the 30-s, 60-s, and 120-s, sham and control cohort were 60%, 60%, 0%, 100%, and 50%, respectively. Signs of bleeding and heat damage were common findings in the evaluation of stereomicroscopic observations. Histological examination could be performed in all but one embryo. Heat damage, bleeding, thrombosis, and leukocyte infiltration and hyperemia were regular findings in H&E-stained cuts. A complete absence of Ki67 staining was recorded in 33.3% and 50% of embryos in the 30-s and 60-s cohorts that survived until ED 14, respectively.

CONCLUSIONS

The CAM model is a feasible and suiting research model for tumor RFA with many advantages over other animal models. It offers the opportunity to conduct in vivo research under standardized conditions. Further studies are needed to optimize this model for tumor ablations in order to explore promising but unrefined strategies like the combination of RFA and immunotherapy.

RELEVANCE STATEMENT

The chick chorioallantoic membrane model allows in vivo research on tumor radiofrequency ablation under standardized conditions that may enable enhanced understanding on combined therapies while ensuring animal welfare in concordance with the "Three Rs."

KEY POINTS

• The chorioallantoic membrane model is feasible and suiting for tumor radiofrequency ablation. • Radiofrequency ablation regularly achieved reduction but not eradication of Ki67 staining. • Histological evaluation showed findings comparable to changes in humans after RFA. • The chorioallantoic membrane model can enable studies on combined therapies after optimization.

Beyond the Knife in Renal Cell Carcinoma: A Systematic Review-To Ablate or Not to Ablate?

Intensified systemic therapy in metastatic renal cell carcinoma (mRCC) has led to improved patient outcomes. Patients commonly require local control of one or a few metastases. The aim was to evaluate metastasis-directed ablative therapies in extracranial mRCC. Two databases and one registry were searched, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, for all prospective and matched-pair case-control mRCC studies of radiofrequency ablation (RFA), cryotherapy, microwave ablation (MWA), and stereotactic body radiotherapy (SBRT). Eighteen studies were identified. Fourteen investigated SBRT in 424 patients. Four thermal ablation studies were identified: two cryotherapy (56 patients) and two RFA studies (90 patients). The median participant number was 30 (range 12-69). The combined median follow-up was 17.3 months (range 8-52). Four SBRT studies reported local control (LC) at 12 months, median 84.4% (range 82.5-93). Seven studies (six SBRT and one cryotherapy) reported an LC rate of median 87% (79-100%). Median overall survival (OS) was reported in eight studies (five SBRT, two cryotherapy, and one RFA) with a median of 22.7 months (range 6.7-not reached). Median progression-free survival was reported in seven studies (five SBRT, one cryotherapy, and one RFA); the median was 9.3 months (range 3.0-22.7 months). Grade ≥ 3 toxicity ranged from 1.7% to 10%. SBRT has excellent local control outcomes and acceptable toxicity. Only four eligible thermal ablative studies were identified and could not be compared with SBRT. Translationally rich definitive studies are warranted.

Radiofrequency ablation for the management of pancreatic mass lesions

PURPOSE OF REVIEW

Patients with pancreatic tumors may have limited treatment options. Pancreatic tumor ablation is a novel and emerging treatment modality which can now be performed using endoscopic ultrasound (EUS) guidance. This modality is well suited to guide energy delivery for radiofrequency ablation (RFA) and microwave ablation. These approaches provide minimally invasive, nonsurgical methods for delivering energy to ablate pancreatic tumors in situ. This review summarizes the current data and safety profile for ablation in managing pancreatic cancer and pancreatic neuroendocrine tumors.

RECENT FINDINGS

RFA uses thermal energy to induce cell death by coagulative necrosis and protein denaturation. Studies have reported increased overall survival in patients with pancreatic tumors treated with EUS-guided RFA in a multimodality systemic approach and when used in palliative surgeries. Radiofrequency ablation may have corollary benefits in inducing an immune-modulatory effect. Tumor marker carbohydrate antigen 19-9 has been reported to decrease in response to RFA. Microwave ablation is an emerging modality.

SUMMARY

RFA utilizes focal thermal energy to induce cell death. RFA has been applied through open, laparoscopic, and radiographic modalities. EUS-guided approaches are now allowing RFA and microwave ablation to be performed for pancreatic tumors in situ.

Endoscopic biliary treatment of unresectable cholangiocarcinoma: A meta-analysis of survival outcomes and systematic review

BACKGROUND

Endoscopic radiofrequency ablation (ERFA), percutaneous radiofrequency ablation (PRFA), and photodynamic therapy (PDT), when used in conjunction with conventional biliary stenting, have demonstrated a survival benefit in patients with unresectable cholangiocarcinoma.

AIM

To compare pooled survival outcomes, adverse event rates, and mean stent patency for those undergoing these procedures.

METHODS

A comprehensive literature review of published studies and abstracts from January 2011 to December 2020 was performed comparing survival outcomes in patients undergoing ERFA with stenting, biliary stenting alone, PRFA with stenting, and PDT with stenting for unresectable cholangiocarcinoma (CCA).

RESULTS

Data from four studies demonstrated a pooled mean survival favoring ERFA as compared to biliary stenting alone (12.0 ± 0.9 mo vs 6.8 ± 0.3 mo, P < 0.001) as well as statistically improved median survival time (13 mo vs 8 mo, P < 0.001). Both ERFA with stenting and PRFA with stenting groups demonstrated statistical superiority to biliary stenting alone (P < 0.001 and P = 0.004, respectively). However, when comparing ERFA to PRFA, pooled data demonstrated overall higher mean survival in the ERFA with stenting cohort as compared to PRFA with stent cohort (12.0 + 0.9 mo vs 8.1 + 2.1 mo, P < 0.0001). Data from two studies demonstrated a pooled median survival favoring ERFA with stenting as compared to PDT with stenting (11.3 mo vs 8.5 mo, P = 0.02).

CONCLUSION

While further prospective, randomized studies are needed to assess efficacy of ERFA, our meta-analysis demonstrated that this technique offers endoscopists a reasonable palliative method by which to treat patients with unresectable CCA that results in longer survival as compared to biliary stenting alone, percutaneous radiofrequency ablation with biliary stenting, and PDT with biliary stenting as well as an acceptable adverse event profile based on available published data.

Minimally invasive techniques in benign and malignant adrenal tumors

Minimally invasive adrenalectomy has become the main treatment modality for most adrenal lesions. Both laparoscopic transabdominal and retroperitoneoscopic approaches are safe and feasible options, each with respective advantages, including better surgical outcomes, fewer complications, and faster recovery over open adrenalectomy. While open surgery remains a valid modality in treatment of adrenocortical cancer in the presence of some findings such as invasion, robotic platforms, and minimally invasive surgery have gained popularity as technology continues to evolve. Organ preservation during adrenalectomy is feasible in some conditions to prevent adrenal insufficiency. Ablative technologies are increasingly utilized in benign and malignant tumors, including the adrenal gland, with various outcomes. A multidisciplinary team, an experienced surgeon, and a high-volume center are recommended for any surgical approaches and management of adrenal lesions. This review article evaluated recent findings and current evidence on minimally invasive adrenalectomy.

Image-guided stent-directed irreversible electroporation for circumferential ablation in the rat esophagus

Background: Irreversible electroporation (IRE) has been investigated in the alimentary tract; however, the lack of dedicated electrodes and insufficient tissue responses made its application limited. The aim of this study was to investigate the efficacy and safety of image-guided stent-directed IRE in the rat esophagus. Methods: The bipolar self-expandable electrode (SE) was developed using the braiding technique. A finite element analysis was performed to validate optimal electrical field strength for the rat esophagus. A total of 40 out of 50 rats received stent-directed IRE and were sacrificed at 10 h, 3 days, 7 days, and 28 days of 10 each. The remaining ten rats underwent a sham procedure. The outcomes of stent-directed IRE were assessed by esophagography and histological responses. Results: Stent-directed IRE was technically successful in all rats with mild muscle contraction. The heart rate dropped immediately and gradually recovered at 180 s. TUNEL and caspase-3 with submucosal thickness significantly increased at 10 h and Day 3 compared with those of the sham control (all p < 0.001). The thickness of epithelial layers with collagen deposition significantly decreased at 10 h and Day 3 (all p < 0.001), however, increased at Day 7 compared with that of the sham control (all p < 0.05). The Ki67-positive deposition significantly increased at Day 3 and 7 compared with that of the sham control (all p < 0.001). All variables were similar to those of the sham control at Day 28. Conclusion: Image-guided stent-directed IRE was effective and safe in the rat esophagus. It seems to have effectively and evenly induced cell death and gradually recovered with cellular regeneration.

Interventional oncology: new techniques and new devices

Interventional oncology is a rapidly emerging field in the treatment of cancer. Minimally invasive techniques such as transarterial embolization with chemotherapeutic and radioactive agents are established therapies and are found in multiple guidelines for the management of primary and metastatic liver lesions. Percutaneous ablation is also an alternative to surgery for small liver, renal, and pancreatic tumors. Recent research in the niche of interventional oncology has focused on improving outcomes of established techniques in addition to the development of novel therapies. In this review, we address the recent and current advancements in devices, technologies, and techniques of chemoembolization and ablation: thermal ablation, histotripsy, high-intensity focused ultrasound, embolization strategies, liquid embolic agents, and local immunotherapy/antiviral therapies.

Efficacy and safety of endoscopic ultrasound-guided radiofrequency ablation for management of pancreatic lesions: a systematic review and meta-analysis

BACKGROUND

Radiofrequency ablation (RFA) has been used to treat various abdominal tumors including pancreatic tumors. Multiple approaches such as laparoscopic, open, and percutaneous have been used for pancreatic tissue ablation. More recently, endoscopic ultrasound (EUS)-guided RFA has emerged as a new technique for pancreatic tissue ablation. The role of EUS-RFA in management of pancreatic lesions is still not well-established. In this study, our aim is to assess efficacy and safety of EUS-RFA for management of pancreatic lesions.

METHODS

MEDLINE, Scopus, and Cochrane Library databases were searched to identify studies reporting EUS-RFA of pancreatic lesions with outcomes of interest. Studies with <5 patients were excluded. Clinical success was defined as symptom resolution, decrease in tumor size, and/or evidence of necrosis on radiologic imaging. Efficacy was assessed by the pooled clinical response rate whereas safety was assessed by the pooled adverse events rate. Heterogeneity was assessed using I2. Pooled estimates and the 95% CI were calculated using random-effect model.

RESULTS

Ten studies (5 retrospective and 5 prospective) involving 115 patients with 125 pancreatic lesions were included. 152 EUS-RFA procedures were performed. The lesions comprised of 37.6% non-functional neuroendocrine tumors (NFNETs), 15.4% were insulinomas, 26.5% were pancreatic cystic neoplasms (PCNs), and 19.7% were pancreatic adenocarcinomas. The majority were present in the pancreatic head (40.2%), 38.3% in the body, 11.2% in the tail, and 10.3% in the uncinate process. Pooled overall clinical response rate was 88.9% (95% CI: 82.4-93.7, I2=38.1%). Pooled overall adverse events rate was 6.7% (95% CI: 3.4-11.7, I2=34.0%). The most common complication was acute pancreatitis (3.3%) followed by pancreatic duct stenosis, peripancreatic fluid collection, and ascites (2.8%) each. Only one case of perforation was reported with pooled rate of (2.1%).

DISCUSSION

This study demonstrates that EUS-RFA is an effective treatment modality for pancreatic lesions, especially functional neuroendocrine tumors such as insulinomas.

Radiofrequency and microwave ablation for treatment of recurrent gynecologic malignancies

OBJECTIVE

Radiofrequency ablation and microwave ablation are used to vaporize tumors not amenable to surgical resection. We sought to evaluate the safety and efficacy of radiofrequency and microwave ablation for the treatment of isolated lesions in patients with recurrent gynecologic malignancy.

METHODS

Patients with gynecologic malignancies treated with radiofrequency or microwave ablation at a university-affiliated cancer center from April 2007 to January 2020 were evaluated. Clinical records were reviewed for number of prior chemotherapy regimens, response to ablation, time to progression, and location of progression.

RESULTS

Thirty-two patients received ablative therapy for treatment of isolated recurrences. Seventeen (53%) patients had ovarian cancer, seven (22%) had endometrial cancer, and eight (25%) had cervical cancer. Thirteen (41%) patients received radiofrequency ablation and 19 (59%) received microwave ablation. Patients had a median of 2 (range 1-12) prior lines of chemotherapy. Sixteen (50%) patients achieved a partial or complete response with two patients experiencing no progression at time of submission. Six (19%) patients had stable disease and 10 (31%) patients had progression at time of initial follow-up imaging. Median progression-free survival for the cohort was 7.3 months (range 1.4-64.7). No significant improvement in median progression-free survival was seen with the addition of adjuvant systemic therapy to radiofrequency or microwave ablation (6.9 vs 7.7 months; HR 0.7, 95% CI 0.3 to 1.7). Clinical benefit, defined as absence of definitive progression at the site of ablation or new target lesions at 4 months, was seen in 22 (68.8%) patients. No major complications occurred, with two patients reporting pain or weakness at the site of ablation.

CONCLUSION

Radiofrequency and microwave ablation demonstrated that 68.8% (n=22) of patients experienced clinical benefit at 4 months. Ablative therapy may be considered for the treatment of isolated lesions in patients with recurrent gynecologic malignancies.

[Recent Updates on Endoscopic Retrograde Cholangiography-guided Intraductal Radiofrequency Ablation for Malignant Biliary Stricture]

Malignant biliary strictures are caused by pancreatobiliary cancer and other metastatic malignancies. Most of them are unresectable at diagnosis with a dismal prognosis. Various new ablation methods have been introduced. Of them, ERCP-guided intraductal radiofrequency ablation (ID-RFA) appears to be the most promising minimally invasive endoscopic treatment by delivering a high-frequency alternating current to the target tissue, leading to coagulative necrosis. Thus far, many studies have provided evidence that ERCP-guided ID-RFA is a safe, feasible, and effective treatment modality for stent patency and overall survival. Compared to other ablation treatments, ERCP-guided ID-RFA has several advantages, including ease of delivery, controlled application of thermal energy, low cost, and fewer systemic side effects with an acceptable safety profile. Therefore, ERCP-guided ID-RFA can be considered an adjunctive treatment for the palliation of unresectable malignant biliary strictures. On the other hand, the decision of local ablation treatment should be individualized by multidisciplinary team support due to the lack of comparative studies.

Oligometastatic breast cancer: Are we there yet?

Patients with metastatic breast cancer are usually considered incurable. Recent advances have resulted in significant improvements in survival for patients with metastatic breast cancer. Due to the lack of randomised trials and heterogeneous disease biology, treatment decisions for patients with oligometastatic breast cancer vary widely. Some patients are treated similar to those with widespread disease while others are treated more aggressively. We conducted a review of the evidence for treatment options in oligometastatic breast cancer and consulted ClinicalTrials.gov to explore currently accruing or studies in development aimed at investigating oligometastatic disease in breast cancer. Surgery to the primary tumour in patients with metastatic breast cancer has failed to show any advantage over systemic therapy. However, there may be a benefit in women with controlled systemic disease who are hormone receptor positive with bone-predominant metastasis. Stereotactic radiotherapy has gained increased interest in this setting due to its excellent efficacy and lower rates of associated toxicity. A significant challenge remains in identifying the patient population who would benefit from such an approach, and to do so, we need to understand the distinct biology of oligometastatic breast cancer. Unique miRNA expression and low levels of tumour infiltrating lymphocytes in the immune micro-environment have been described in tumour tissues in patients with oligometastatic breast cancer. There is ongoing research aimed to better characterise these tumours, thus, allowing the selection of patients who would truly benefit from multi-modality treatment in an attempt for long-term survival and cure.

Ultrasonography-guided radiofrequency ablation combined with lauromacrogol sclerotherapy for mixed thyroid nodules

OBJECTIVE

To evaluate the safety and effectiveness of ultrasonography-guided radiofrequency ablation combined with lauromacrogol foam sclerotherapy for the treatment of mixed thyroid nodules.

METHODS

One hundred and nineteen patients with benign mixed thyroid nodules were included in this study. In all patients, radiofrequency ablation was performed on the solid components of nodules, and the cystic areas of nodules were treated with aspiration, irrigation with lauromacrogol injection and foam sclerotherapy. The nodule volume reduction ratio and thyroid-related laboratory tests were measured during operation and at 1, 3, 6, and 12 months after operation, and intraoperative and postoperative complications were recorded.

RESULTS

A total of 136 mixed thyroid nodules from 119 patients all achieved complete ablation. At 1, 3, 6, and 12 months after treatment, the nodule volume decreased gradually while the volume reduction ratio increased gradually (P<0.05). The thyroid function of all patients returned to normal after operation, but 3 patients exhibited cyst recurrence. After the operation, no serious complications occurred.

CONCLUSION

Ultrasonography-guided radiofrequency ablation combined with lauromacrogol sclerotherapy is a safe and effective method for the treatment of mixed thyroid nodules with less surgical trauma and low incidence of complications.

The Safety of Radiofrequency Ablation Using a Novel Temperature-Controlled Probe for the Treatment of Residual Intraductal Lesions after Endoscopic Papillectomy

Background/Aims

Treatment of residual intraductal lesions after endoscopic papillectomy for ampullary adenomas is relatively difficult. Few studies have been conducted using intraductal radiofrequency ablation (RFA) in the treatment of such lesions, and no study has aimed to reduce the side effects of excessive heat caused by RFA. Recently, a temperature-controlled RFA probe was developed to avoid excessive heat. This study aimed to investigate the safety of this new RFA probe in the treatment of intraductal lesions of ampullary adenoma.

Methods

Patients who received RFA for residual intraductal lesions after endoscopic papillectomy between November 2017 and June 2019 were retrospectively reviewed. A novel temperature- controlled probe (ELRA) was used for intraductal RFA, and clinical data including adverse events were collected.

Results

Ten patients were included in this study. Intraductal adenomas showed low-grade dysplasia in eight patients and high-grade dysplasia in two patients. The median diameter of intraductal adenomas was 9 mm (range, 5 to 10 mm) in the common bile duct and 5 mm (range, 4 to 11 mm) in the pancreatic duct. Adverse events occurred in three patients (30.0%), of which two were mild pancreatitis and one was asymptomatic biliary stricture. Over a median follow-up period of 253 days, only one patient underwent additional surgery, as the remainder showed no adenomatous lesions on follow-up biopsies.

Conclusions

The new temperature-controlled RFA probe can be used with acceptable safety for the treatment of residual intraductal lesions after endoscopic papillectomy. Further evaluation through future prospective studies is needed.

Comparative outcomes of radio frequency ablation versus partial nephrectomy for T1 renal tumors: a systematic review

Background

The role of radio frequency ablation (RFA) in small renal tumors remains controversial. This systematic review was performed to compare clinical outcomes of RFA versus partial nephrectomy (PN) for the treatment of T1 renal tumors.

Methods

A total of 11 studies including 2,397 patients were analyzed in this systematic review after searching the databases of PubMed, EMBASE and Web of Science. P value and odds ratio (OR)/hazard ratio (HR) with 95% confidence interval (CI) were used to evaluate the strength of the association.

Results

A total of six studies (2,056 patients) provided either survival curves or HR and its 95% CI, demonstrating that the majority of the patients with RFA treatment tended to exhibit a similar long-term survival rate to those with PN treatment. In addition, according to four studies, no differences were found in the overall rate of complications between the two groups. Furthermore, there were significant differences in glomerular filtration rate (GFR) change between the two methods in four studies but no differences were observed in other two.

Conclusions

Our systematic review indicated that RFA is an effective treatment option which could provide comparable oncologic outcomes to PN. Moreover, it may present obvious advantages in renal function preservation.

Early and Late Fusion Machine Learning on Multi-Frequency Electrical Impedance Data to Improve Radiofrequency Ablation Monitoring

Radiofrequency ablation (RFA) is a popular modality for tumor treatment. However, inexpensive real-time monitoring of RFA within multiple tissue types is still an ongoing research topic. The objective of this study is to utilize multi-frequency electrical impedance data within real-time RFA depth estimation through data fusion schemes that include non-linear machine learning (ML) models. Multi-frequency tissue complex electrical impedance measurements are used to provide input data to the data fusion schemes. Our results show that the fusion schemes significantly decrease both the spread of residuals and the mean of the residuals for depth estimation. Thus, data fusion can be a significant tool for use in improving the performance of ML-based monitoring for RFA.

Real-Time Radiofrequency Ablation Lesion Depth Estimation Using Multi-frequency Impedance With a Deep Neural Network and Tree-Based Ensembles

OBJECTIVE

Design and optimization of statistical models for use in methods for estimating radiofrequency ablation (RFA) lesion depths in soft real-time performance.

METHODS

Using tissue multi-frequency complex electrical impedance data collected from a low-cost embedded system, a deep neural network (NN) and tree-based ensembles (TEs) were trained for estimating the RFA lesion depth via regression.

RESULTS

Addition of frequency sweep data, previous depth data, and previous RF power state data boosted accuracy of the statistical models. The root mean square errors were 2 mm for NN and 0.5 mm for TEs for previous statistical models and the root mean square errors were 0.4 mm for NN and 0.04 mm for TEs for the statistical models presented in this paper. Simulation ablation performance showed a mean difference against physical measurements of 0.5 ±0.2 mm for the NN-based depth estimation method and 0.7 ±0.4 mm for the TE-based depth estimation method.

CONCLUSION

The results show that multi-frequency data significantly improves the depth estimation performance of the statistical models.

SIGNIFICANCE

The RFA lesion depth estimation methods presented in this work achieve millimeter-resolution accuracy with soft real-time performance on an ARMv7-based embedded system for potential translation to clinical RFA technologies.

Percutaneous Intramyocardial Septal Radiofrequency Ablation for Hypertrophic Obstructive Cardiomyopathy

BACKGROUND

In patients with disabling symptoms caused by hypertrophic obstructive cardiomyopathy (HOCM), echocardiography-guided percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) could be a less invasive treatment option.

OBJECTIVES

This study aimed to investigate the safety and efficacy of the PIMSRA for left ventricular outflow tract (LVOT) gradient reduction in HOCM.

METHODS

The study enrolled 15 patients with HOCM. These patients underwent electrocardiography, imaging, and blood biochemistry examination over 6 months of follow-up.

RESULTS

At 6 months of follow-up, patients showed significant reductions in peak LVOT gradients (resting gradient: from 88.00 [66.00] mm Hg to 11.00 [6.00] mm Hg; p = 0.001; stress-induced gradient: from 117.00 [81.00] mm Hg to 25.00 [20.00] mm Hg; p = 0.005) and interventricular septum (IVS) thickness (anterior IVS: from 25.00 [21.00] mm to 14.00 [12.00] mm; p = 0.001; posterior IVS: from 24.00 [21.00] mm to 14.00 [11.50] mm; p = 0.001). The reductions in IVS thickness and LVOT gradients were associated with improvement in New York Heart Association functional classification (from 3.00 [2.00] to 1.00 [1.00]; p < 0.001), total exercise time (from 6.00 [5.50] min to 9.00 [8.00] min; p = 0.007), and pro B-type natriuretic peptide levels (from 924.00 [370.45] pg/ml to 137.45 [75.73] pg/ml; p = 0.028). No patient had bundle branch block or complete heart block.

CONCLUSIONS

PIMSRA is a safe and effective treatment approach for severe, symptomatic HOCM and results in sustained improvement in exercise capacity, persistent reduction in LVOT gradient, and sustained improvement in cardiac function.

Clinical assessment of magnetic resonance imaging-guided radiofrequency ablation for breast cancer

The aim of the present study was to investigate the efficacy of magnetic resonance imaging (MRI)-guided radiofrequency ablation (RFA) for breast cancer patients who cannot undergo traditional surgery. A total of 10 patients were treated by MRI-guided RFA, of whom 6 had stage IV disease (lung metastasis n=3, bone metastasis n=1, liver metastasis n=1 and mediastinal metastasis n=1) and the remaining 4 patients, who refused surgery, had stage III disease accompanied by severe underlying conditions. The changes in feasibility, tumor volume, bleeding, local recurrence, metastasis and complications were evaluated after RFA. The patients were followed up at 1, 3, 6 and 12 months, and annually thereafter. A total of 14 RFA sessions were successfully performed (100%) in the 10 patients, among whom 7 patients underwent a single RFA session, 2 patients underwent two sessions, and 1 patient underwent three sessions. Compared with pre-RFA, the volume of the tumors at 6 months after RFA was markedly decreased. There was no local tumor recurrence or metastasis detected during a mean follow-up period of 19.5±3.46 months, and no major complications were reported. Therefore, RFA was found to be a minimally invasive and feasible treatment method in the present study, and MRI-guided RFA may be a promising alternative option for breast cancer patients who are unable to tolerate surgery. However, more prospective studies on the applicability of RFA in breast cancer are required.

Real-time monitoring radiofrequency ablation using tree-based ensemble learning models

BACKGROUND

Radiofrequency ablation is a minimally-invasive treatment method that aims to destroy undesired tissue by exposing it to alternating current in the 100 kHz-800 kHz frequency range and heating it until it is destroyed via coagulative necrosis. Ablation treatment is gaining momentum especially in cancer research, where the undesired tissue is a malignant tumor. While ablating the tumor with an electrode or catheter is an easy task, real-time monitoring the ablation process is a must in order to maintain the reliability of the treatment. Common methods for this monitoring task have proven to be accurate, however, they are all time-consuming or require expensive equipment, which makes the clinical ablation process more cumbersome and expensive due to the time-dependent nature of the clinical procedure.

METHODS

A machine learning (ML) approach is presented that aims to reduce the monitoring time while keeping the accuracy of the conventional methods. Two different hardware setups are used to perform the ablation and collect impedance data at the same time and different ML algorithms are tested to predict the ablation depth in 3 dimensions, based on the collected data.

RESULTS

Both the random forest and adaptive boosting (adaboost) models had over 98% R² on the data collected with the embedded system-based hardware instrumentation setup, outperforming Neural Network-based models.

CONCLUSIONS

It is shown that an optimal pair of hardware setup and ML algorithm (Adaboost) is able to control the ablation by estimating the lesion depth within a test average of 0.3mm while keeping the estimation time within 10ms on a ×86-64 workstation.

High-Intensity Focused Ultrasonography and Radiofrequency Ablation of Renal Cell Carcinoma Arisen in Transplanted Kidneys: Single-Center Experience With Long-Term Follow-Up and Review of Literature

The purpose of this article is to retrospectively evaluate the long-term outcome of patients treated with percutaneous thermoablation for renal cell carcinomas that have arisen in kidney grafts. Between April 2008 and February 2011, we treated 3 patients with renal cell carcinoma on a transplanted kidney: 2 cases were treated with high-intensity focused ultrasonography and 1 patient with radio frequency ablation. Postprocedural ultrasonography did not reveal any complications, and contrast-enhanced ultrasonography showed an avascular area in the treated nodules. None of the patients had recurrent tumors during a long-term clinical and radiologic follow-up (81, 73, and 43 months, respectively).

Ultrasound single-phase CBE imaging for monitoring radiofrequency ablation

Radiofrequency (RF) ablation (RFA) is the most commonly used minimally invasive procedure for thermal ablation of liver tumors. Ultrasound not only provides real-time feedback of the electrode location for RFA guidance but also enables visualization of the tissue temperature. Changes in backscattered energy (CBE) have been widely applied to ultrasound temperature imaging for assessing thermal ablation. Pilot studies have revealed that significant shadowing features appear in CBE imaging and are caused by the electrode and RFA-induced gas bubbles. To resolve this problem, the current study proposed ultrasound single-phase CBE imaging based on positive CBE values. An in vitro model with tissue samples derived from the porcine tenderloin was used to validate the proposed method. During RFA with various electrode lengths, ultrasound scans of tissue samples were obtained using a clinical ultrasound scanner equipped with a convex array transducer of 3 MHz. Raw image data comprising 256 scan lines of backscattered RF signals were acquired for B-mode, conventional CBE, and single-phase CBE imaging by using the proposed algorithmic scheme. The ablation sizes estimated using CBE imaging and gross examinations were compared to calculate the correlation coefficient. The experimental results indicated that single-phase CBE imaging largely suppressed artificial CBE information in the shadowed region. Moreover, compared with conventional CBE imaging, single-phase CBE imaging provided a more accurate estimation of ablation sizes (the correlation coefficient was higher than 0.8).

Novel temperature-controlled RFA probe for treatment of blocked metal biliary stents in patients with pancreaticobiliary cancers: initial experience

BACKGROUND AND STUDY AIMS

 Radiofrequency ablation (RFA) is used to treat blocked biliary stents in patients with pancreaticobiliary (PB) tumors with varying results. We report our experience with a novel temperature-controlled probe for treatment of blocked metal stents.

PATIENTS AND METHODS

 Patients with histologically proven PB cancers and a blocked biliary stents were treated using ELRATM electrode (Taewoong Medical) under fluoroscopic guidance. Demographics, clinical outcome, stricture diameter improvements, complications and mortality at 30 days were prospectively recorded.

RESULTS

 Nine procedures were performed on seven patients (4 male, 3 female); mean age 65.33 (range 56 - 82 years). Mean stricture diameter prior to RFA was 1.13 mm (SD ± 0.54) and 4.42 mm (SD ± 1.54) following RFA ( P  < 0.0001). Five of seven patients (71 %) required additional stents to ensure optimal drainage. There were no procedure-related complications. Mean follow-up was 193.55 days (range 31 - 540) and three of nine patients (33 %) died due to terminal cancer.

CONCLUSION

These are the first reported data on use of a temperature-controlled RFA catheter in humans to treat blocked metal biliary stents. The device is safe but further randomized trials are required to establish the efficacy and survival benefits of this probe.

The need for multidisciplinarity in specialist training to optimize future patient care

Harmonious interactions between radiation, medical, interventional and surgical oncologists, as well as other members of multidisciplinary teams, are essential for the optimization of patient care in oncology. This multidisciplinary approach is particularly important in the current landscape, in which standard-of-care approaches to cancer treatment are evolving towards highly targeted treatments, precise image guidance and personalized cancer therapy. Herein, we highlight the importance of multidisciplinarity and interdisciplinarity at all levels of clinical oncology training. Potential deficits in the current career development pathways and suggested strategies to broaden clinical training and research are presented, with specific emphasis on the merits of trainee involvement in functional multidisciplinary teams. Finally, the importance of training in multidisciplinary research is discussed, with the expectation that this awareness will yield the most fertile ground for future discoveries. Our key message is for cancer professionals to fulfil their duty in ensuring that trainees appreciate the importance of multidisciplinary research and practice.

Ablative techniques for the treatment of benign and malignant breast tumours

Minimally invasive techniques like high intensity focused ultrasound, radiofrequency ablation, cryo-ablation, laser ablation and microwave ablation have been used to treat both breast fibroadenomata and breast cancer as an alternative to surgical excision, potentially reducing the complications, improving cosmesis and reducing hospital stay. This review describes the most common minimally invasive techniques available, their history and some of the studies performed with these techniques in both benign and malignant lesions. In addition we described some of the difficulties of using these minimally invasive techniques such as optimization of anaesthesia, imaging and immobilisation in order to increase the complete histopathological ablation rates.

Review of endoscopic radiofrequency in biliopancreatic tumours with emphasis on clinical benefits, controversies and safety

Most pancreatic cancers and extrahepatic cholangiocarcinomas are unresectable at the time of diagnosis, and even in case of a resectable cancer, for elderly or patients with coexistent comorbidities, surgery is not an option. Current treatment alternatives in these scenarios are very limited. Biliary stenting with self-expanding metal stents (SEMS) is the mainstay palliative treatment of biliary obstruction due to unresectable pancreatic cancer or cholangiocarcinoma. Nevertheless, more than 50% of SEMS become occluded after 6 mo due to tumour over- and ingrowth, leading to hospital readmissions and reinterventions that significantly impair quality of life. Regimes of chemotherapy or chemoradiotherapy also provide minimal survival benefits. Therefore, novel therapies are eagerly awaited. Radiofrequency (RF) energy causes coagulative necrosis leading to local destruction of the accessed malignant tissue and has an established role in the treatment of malignancies in several solid organs, especially liver cancers. However, pancreatic and extrahepatic biliary cancers are not easily accessed by a percutaneous route, making the procedure dangerous. Over the past five years, the development of dedicated devices compatible with endoscopic instruments has offered a minimally invasive option for RF energy delivery in biliopancreatic cancers. Emerging experience with endoscopic RF ablation (RFA) in this setting has been reported in the literature, but little is known about its feasibility, efficacy and safety. A literature review makes it clear that RFA in biliopancreatic tumours is feasible with high rates of technical success and acceptable safety profile. Although available data suggest a benefit of survival with RFA, there is not enough evidence to draw a firm conclusion about its efficacy. For this reason, prospective randomized trials comparing RFA with standard palliative treatments with quality-of-life and survival endpoints are required. Anecdotal reports have also highlighted a potential curative role of RFA in small pancreatic tumours and benign conditions, such as ductal extension of ampullomas, intrahepatic adenomas or non-tumoural biliary strictures. These newest indications also deserve further examination in larger series of studies.

Monitoring Radiofrequency Ablation Using Ultrasound Envelope Statistics and Shear Wave Elastography in the Periablation Period: An In Vitro Feasibility Study

Radiofrequency ablation (RFA) is a minimally invasive method for treating tumors. Shear wave elastography (SWE) has been widely applied in evaluating tissue stiffness and final ablation size after RFA. However, the usefulness of periablation SWE imaging in assessing RFA remains unclear. Therefore, this study investigated the correlation between periablation SWE imaging and final ablation size. An in vitro porcine liver model was used for experimental validation (n = 36). During RFA with a power of 50 W, SWE images were collected using a clinical ultrasound system. To evaluate the effects of tissue temperature and gas bubbles during RFA, changes in the ablation temperature were recorded, and image echo patterns were measured using B-mode and ultrasound statistical parametric images. After RFA, the gross pathology of each tissue sample was compared with the region of change in the corresponding periablation SWE image. The experimental results showed that the tissue temperature at the ablation site varied between 70°C and 100°C. Hyperechoic regions and changes were observed in the echo amplitude distribution induced by gas bubbles. Under this condition, the confounding effects (including the temperature increase, tissue stiffness increase, and presence of gas bubbles) resulted in artifacts in the periablation SWE images, and the corresponding region correlated with the estimated final ablation size obtained from the gross pathology (r = 0.8). The findings confirm the feasibility of using periablation SWE imaging in assessing RFA.

Role of imaging for patients with colorectal hepatic metastases: what the radiologist needs to know

Surgical resection of colorectal metastatic disease has increased as surgeons have adopted a more aggressive ideology. Current exclusion criteria are patients for whom a negative resection margin is not feasible or a future liver remnant (FLR) of greater than 20% is not achievable. The goal of preoperative imaging is to identify the number and distribution of liver metastases, in addition to establishing their relation to relevant intrahepatic structures. FLR can be calculated utilizing cross-sectional imaging to select out patients at risk for hepatic dysfunction after resection. MRI, specifically with gadoxetic acid contrast, is currently the preferred modality for assessment of hepatic involvement for patients with newly diagnosed colorectal cancer, to include those who have undergone neoadjuvant chemotherapy. Employment of liver-directed therapies has recently expanded and they may provide an alternative to hepatectomy in order to obtain locoregional control in poor surgical candidates or convert patients with initially unresectable disease into surgical candidates.

Comparison of real-time contrast-enhanced ultrasonography and standard ultrasonography in liver cancer microwave ablation

Primary liver cancer has a high incidence and high mortality rates, and currently the only viable option is surgery, although there are a number of difficulties related to this method. The aim of the present study was to investigate the potential advantages of the real-time contrast-enhanced ultrasonography (CEUS) for microwave ablation of primary liver cancer. One hundred patients with primary liver cancer were included in the study. The patients were divided into the ordinary ultrasonography and the CEUS groups. For the ordinary ultrasonography group, the ordinary ultrasonography-guided microwave ablation method was used, while microwave ablation under the guidance of CEUS was conducted for the CEUS group. The size of lesions and clearness of the tumor boundary prior to surgery in the two groups were compared. Additionally, postoperative complications and the survival rate were monitored. Lesion boundary areas measured by CEUS were significantly larger than those measured with ordinary ultrasonography. The incidence rate of postoperative pain, fever, intra-abdominal hemorrhage and infection and other complications in the ordinary ultrasonography group were significantly higher than that in the CEUS group. The tumor recurrence rate in the CEUS group was significantly lower than that in the ordinary ultrasonography group. Seventy-two percent of patients in the CEUS group showed no progress, compared to 48% of in the ordinary ultrasonography group. The progress-free survival rate in the CEUS group after 6 months was significantly higher than that in the ordinary ultrasonography group. Disease-free survival time in the CEUS group was considerably longer than the control group. In conclusion, the guidance of real-time CEUS on the primary liver cancer microwave ablation treatment can achieve good intra-operative results. It offers a real-time guidance effect, improves survival time and reduces the incidence of complications.

Incomplete radiofrequency ablation accelerates proliferation and angiogenesis of residual lung carcinomas via HSP70/HIF-1α

Radiofrequency ablation (RFA) therapy has been proved effective and feasible for lung cancer. However, the molecular mechanisms of local lung cancer recurrence following RFA are poorly understood. The present study aimed to evaluate the ability of HSP70/HIF-1α to affect the proliferation and angiogenesis of non-small cell lung cancers (NSCLCs) following insufficient RFA to uncover the molecular mechanisms of local recurrence. In vitro heat treatment was used to establish sublines of NCI-H1650 cells. The NCI-H1650 subline that was established by heat treatment at 54°C had a relatively higher viability and significantly elevated heat tolerance (compared to the parental strain). After treatment with the HSP70 inhibitor VER-155008, the HIF-1α inhibitor YC-1 and PI3K/Akt inhibitor wortmannin, the viability and proliferation rate of the cells was measured. At the same time, HSP70, HIF-1α and Akt were detected by real-time PCR and western blotting. In vivo xenograft tumors were created by subcutaneously inoculating nude mice with NCI-H1650 cells. HSP70, HIF-1α and Akt were detected by western blotting, and CD34 expression was detected by immunohistochemistry before and after RFA or treatment with the VER-155008, YC-1 or wortmannin inhibitors. The heat-adapted NCI-H1650 subline established in vitro had a higher viability and proliferative activity compared to parental cells. Inhibiting HSP70/HIF-1α abolished this difference. Blocking the PI3K/Akt signaling pathway decreased HSP70/HIF-1α expression levels. In vivo, we found that incomplete RFA treatment promoted HSP70/HIF-1α and CD34 expression. Additionally, the combination of RFA and treatment targeting HSP70/HIF-1α resulted in a synergistic reduction in tumor growth compared to incomplete RFA alone. The PI3K/Akt signaling pathway is also involved in regulating HSP70/HIF-1α expression during this process. We conclude that the accelerated proliferation and angiogenesis potential of residual lung carcinomas following RFA treatment was induced by HSP70/HIF-1α, expression of which is regulated by the PI3K/Akt signaling pathway.

Effects of radiation from a radiofrequency identification (RFID) microchip on human cancer cells

PURPOSE

Radiofrequency identification (RFID) microchips are used to remotely identify objects, e.g. an animal in which a chip is implanted. A passive RFID microchip absorbs energy from an external source and emits a radiofrequency identification signal which is then decoded by a detector. In the present study, we investigated the effect of the radiofrequency energy emitted by a RFID microchip on human cancer cells.

MATERIALS AND METHODS

Molt-4 leukemia, BT474 breast cancer, and HepG2 hepatic cancer cells were exposed in vitro to RFID microchip-emitted radiofrequency field for 1 h. Cells were counted before and after exposure. Effects of pretreatment with the spin-trap compound N-tert-butyl-alpha-phenylnitrone or the iron-chelator deferoxamine were also investigated. Results We found that the energy effectively killed/retarded the growth of the three different types of cancer cells, and the effect was blocked by the spin-trap compound or the iron-chelator, whereas an inactive microchip and energy from the external source had no significant effect on the cells. Conclusions Data of the present study suggest that radiofrequency field from the microchip affects cancer cells via the Fenton Reaction. Implantation of RFID microchips in tumors may provide a new method for cancer treatment.

Radiofrequency ablation versus partial nephrectomy for treatment of renal masses: A systematic review and meta-analysis

Our study was to collect the data available in the literature on radiofrequency ablation (RFA) and partial nephrectomy (PN) and conduct a cumulative analysis on perioperative outcomes, renal function outcomes, and survival to evaluate the overall safety and efficacy of RFA versus PN for small renal cell cancer (SRCC). A literature search was carried out using various electronic databases. Data including age, tumor size, comorbid disease, operation duration, hospital stay, pre- and postoperative estimated glomerular filtration rate (eGFR), major and minor complications, and local tumor recurrence and metastasis were collected for meta-analysis. Sixteen studies were included for this meta-analysis. The age of patients treated with RFA was significantly older than that of patients treated with PN [weighted mean difference (WMD) = 5.07 years]. There were more patients with cardiovascular disease in RFA group as compared with PN group [odds ratio (OR) = 4.24] before treatment. RFA was associated with a shorter length of hospital stay compared with PN (WMD = -2.02 days). No significant difference was found in major and minor complications between the two groups (major: OR = 0.74; minor: OR = 0.45). Preoperative eGFR and eGFR decline in RFA patients was significantly lower than that in PN patients (WMD = -7.27 and -4.82, respectively), whereas there was no significant difference in postoperative eGFR (WMD = -1.18). The local tumor recurrence rate in RFA group was higher than that in PN group (OR = 1.81). However, the distant metastasis rate was no statistical difference between the two groups (OR = 1.63). RFA is a suitable therapeutic option for older patients and those at high risk for SRCC because of a low risk of operation and better preservation of renal function.

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.

Oligometastatic breast cancer: a shift from palliative to potentially curative treatment?

A distinctive subset of metastatic breast cancer is represented by the so called 'oligometastatic' disease, characterized by single/few detectable metastatic lesions. A more aggressive multidisciplinary approach can be considered in this patient population: available data report favorable results of 'radical' local therapy for limited metastatic disease at least in a subset of selected patients. Selection bias and the retrospective nature of data do not allow for generalization of the results: the use of such approaches must be individualized and managed within a multidisciplinary team of dedicated specialists. Improvement in surgical and radiation techniques, development of new tools to deliver local chemotherapy, and new procedures (i.e. cryosurgery, laser and microwave ablation) mandate careful evaluation of such single and combined modalities in controlled clinical trials. A more accurate identification of patients with limited metastases and better definition of treatment endpoints will also allow correct patient selection for locally aggressive therapies. This paper focusses on local treatment of the primary tumor and of the most frequent distant disease sites in the presence of oligometastatic disease.

The neutrophil-to-lymphocyte ratio as a predictor for recurrence of colorectal liver metastases following radiofrequency ablation

The purpose of this study was to assess the value of the neutrophil-to-lymphocyte ratio (NLR) as a predictive factor for recurrence of colorectal liver metastases following radiofrequency ablation (RFA) treatment. We retrospectively analyzed clinical data from 98 patients who received routine RFA treatment for colorectal liver metastases. Univariate analyses were conducted to evaluate the effects of preoperative maximum tumor diameter, number of tumors, colon cancer staging, carcinoembryonic antigen levels, and preoperative and postoperative NLRs on disease-free survival (DFS). Statistically significant factors were further analyzed using multivariate Cox regression models to identify independent factors that were predictive of tumor recurrence. The one-, three-, and five-year DFS rates for patient were 66.3, 28.6, and 17.3%, respectively. Univariate analysis showed that preoperative NLR≥2.5 and postoperative increase in NLR were associated with decreased DFS rates. One-, three-, and five-year DFS rates for patients with preoperative NLR≥2.5 were 53.3, 20.0, and 11.1%, whereas patients with preoperative NLR<2.5 had DFS rates of 77.4, 35.8, and 22.6%, respectively (P=0.044). One-, three- and five-year DFS rates for patients with NLRs increased 1 month after RFA treatment were 52.3, 17.1, and 8.6%, while patients with no increased postoperative NLRs had DFS rates of 73.0, 34.9, and 22.2%, respectively (P=0.022). Cox regression analysis showed that postoperative NLR increase was an independent risk factor (P=0.029) for recurrence after RFA treatment in patients with colorectal liver metastases. The present study suggests that patients with preoperative NLRs≥2.5 or increased postoperative NLR are at an increased risk for recurrence after RFA treatment for colorectal liver metastases.

Advances in interventional pulmonology

Interventional pulmonology (IP) remains a rapidly expanding and evolving subspecialty focused on the diagnosis and treatment of complex diseases of the thorax. As the field continues to push the leading edge of medical technology, new procedures allow for novel minimally invasive approaches to old diseases including asthma, chronic obstructive pulmonary disease and metastatic or primary lung malignancy. In addition to technologic advances, IP has matured into a defined subspecialty, requiring formal training necessary to perform the advanced procedures. This need for advanced training has led to the need for standardization of training and the institution of a subspecialty board examination. In this review, we will discuss the dynamic field of IP as well as novel technologies being investigated or employed in the treatment of thoracic disease.

Molecular changes in bone marrow, tumor and serum after conductive ablation of murine 4T1 breast carcinoma

Thermal ablation of solid tumors using conductive interstitial thermal therapy (CITT) produces coagulative necrosis in the center of ablation. Local changes in homeostasis for surviving tumor and systemic changes in circulation and distant organs must be understood and monitored in order to prevent tumor re-growth and metastasis. The purpose of this study was to use a mouse carcinoma model to evaluate molecular changes in the bone marrow and surviving tumor after CITT treatment by quantification of transcripts associated with cancer progression and hyperthermia, serum cytokines, stress proteins and the marrow/tumor cross-talk regulator stromal-derived factor 1. Analysis of 27 genes and 22 proteins with quantitative PCR, ELISA, immunoblotting and multiplex antibody assays revealed that the gene and protein expression in tissue and serum was significantly different between ablated and control mice. The transcripts of four genes (Cxcl12, Sele, Fgf2, Lifr) were significantly higher in the bone marrow of treated mice. Tumors surviving ablation showed significantly lower levels of the Lifr and Sele transcripts. Similarly, the majority of transcripts measured in tumors decreased with treatment. Surviving tumors also contained lower levels of SDF-1α and HIF-1α proteins whereas HSP27 and HSP70 were higher. Of 16 serum chemokines, IFNγ and GM-CSF levels were lower with treatment. These results indicate that CITT ablation causes molecular changes which may slow cancer cell proliferation. However, inhibition of HSP27 may be necessary to control aggressiveness of surviving cancer stem cells. The changes in bone marrow are suggestive of possible increased recruitment of circulatory cancer cells. Therefore, the possibility of heightened bone metastasis after thermal ablation needs to be further investigated and inhibition strategies developed, if warranted.