Image guided tumour ablation

Percutaneous Microwave Coagulation Therapy: A Promising Therapeutic Method for Breaking the Barrier of the Intertumor Heterogeneity

Intertumor heterogeneity is common in various cancers and has been widely accepted as the primary cause of the diversity and variation of the effect of the same treatment on patients with the same type of tumor. Percutaneous microwave coagulation therapy (PMCT) is a minimally invasive and effective approach for destroying tumors by microwave beam under image guidance, which has been applied in lung cancer. However, no previous study has investigated the capability of PMCT solving intertumor heterogeneity. Here, we performed a component analysis of four lung cancer patients' tumor microenvironment (TME) via single-cell RNA sequencing (scRNA-seq) and treated all four cases with PMCT. One patient's TME could be classified into a hot tumor, mainly proinflammatory cytokines, and T cell infiltration. The other three patients' TMEs were cold tumors, where immunosuppressive cells occupied a large proportion, including tumor-associated macrophages and cancer cells. Despite a high level of heterogeneity among their tumor microenvironment compositions, disease type and stage, and basic physical conditions, all four patients presented a stable disease (SD) without any cancer cell detected in the TME of cancer tissues after PMCT. In conclusion, this report uniquely contributed to the knowledge of the PMCT adaptation to tumor heterogeneity. Therefore, PMCT is promising to demonstrate a stable and robust antitumor efficacy in unresectable lung cancers with various TMEs.

Predictive factors of long-term colorectal cancer survival after ultrasound-controlled ablation of hepatic metastases

BACKGROUND AND OBJECTIVE

The risk factors associated to long-term survival were assessed in patients with liver metastases of colorectal carcinoma undergoing ablative therapies.

PATIENTS AND METHODS

Single-centre cohort study, retrospectively analysed and prospectively collected consecutive patients with unresectable metastatic liver disease of colorectal carcinoma treated with ablative therapies between 1996 and 2013. Factors associated with survival time were identified using Cox's proportional hazard model with time-dependent covariates. A forward variable selection based on Akaike information criterion was performed. Relative risk and 95% confidence intervals for each factor were calculated. Statistical significance was set as P<.05.

RESULTS

Seventy-five patients with liver metastases of colorectal cancer, with a mean age of 65.6 (10.3) underwent 106 treatments. Variables selected were good quality of life (RR 0.308, 95% CI 0.150-0.632) and tumour extension (RR 3.070, 95% CI 1.776-5.308). The median overall survival was 18.5 months (95% CI 17.4-24.4). The survival prognosis in median was 13.5 vs. 23.4 months for patients with and without tumour extension, and 23.0 vs. 12.8 months for patients with good and fair or poor quality of life, respectively.

CONCLUSIONS

Good quality of life and tumour extension were the only statistically significant predictors of long-term survival in patients of colorectal carcinoma with liver metastatic disease undergoing ablative treatment with ultrasound.

Percutaneous microwave ablation vs radiofrequency ablation in the treatment of hepatocellular carcinoma

Hepatocellular cancer ranks fifth among cancers and is related to chronic viral hepatitis, alcohol abuse, steatohepatitis and liver autoimmunity. Surgical resection and orthotopic liver transplantation have curative potential, but fewer than 20% of patients are suitable candidates. Interventional treatments are offered to the vast majority of patients. Radiofrequency (RFA) and microwave ablation (MWA) are among the therapeutic modalities, with similar indications which include the presence of up to three lesions, smaller than 3 cm in size, and the absence of extrahepatic disease. The therapeutic effect of both methods relies on thermal injury, but MWA uses an electromagnetic field as opposed to electrical current used in RFA. Unlike MWA, the effect of RFA is partially limited by the heat-sink effect and increased impedance of the ablated tissue. Compared with RFA, MWA attains a more predictable ablation zone, permits simultaneous treatment of multiple lesions, and achieves larger coagulation volumes in a shorter procedural time. Major complications of both methods are comparable and infrequent (approximately 2%-3%), and they include haemorrhage, infection/abscess, visceral organ injury, liver failure, and pneumothorax. RFA may incur the additional complication of skin burns. Nevertheless, there is no compelling evidence for differences in clinical outcomes, including local recurrence rates and survival.

Safety and Efficacy of Ultrasound-Guided Radiofrequency Ablation of Recurrent Colorectal Cancer Liver Metastases after Hepatectomy

INTRODUCTION

To assess the results and outcome of radiofrequency ablation in the treatment of recurrent colorectal liver metastases.

PATIENTS AND METHODS

Between January 2005 and September 2012, we treated 59 patients with recurrent colorectal metastases not amenable to surgery with 77 radiofrequency ablation procedures. Radiofrequency was indicated if oncologic resection was technically not possible or the patient was not fit for major surgery. A total of 91 lesions were treated. The mean number of liver tumors per patient was 1.5, and the mean tumor diameter was 2.3 cm. In 37.5% of the cases, lesions had a subcapsular location, and 34% were close to a vascular structure.

RESULTS

The morbidity rate was 18.7%, and there were no post-procedural deaths. Distant extrahepatic recurrence appeared in 50% of the patients. Local recurrence at the site of ablation appeared in 18% of the lesions. Local recurrence rate was 6% in lesions less than 3 cm and 52% in lesions larger than 3 cm. The size of the lesions (more than 3 cm) was an independent risk factor for local recurrence (p < 0.05). Survival rates at 1, 3, and 5 years were 94.5%, 65.3%, and 21.7%, respectively.

DISCUSSION

Radiofrequency ablation is a safe procedure and allows local tumor control in lesions less than 30 mm (local recurrence of 6%) and provides survival benefits in patients with recurrent colorectal liver metastases.

Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards

OBJECTIVE

To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports.

MATERIALS AND METHODS

Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated.

RESULTS

Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology.

CONCLUSION

The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.

Interventional radiology and the care of the oncology patient

Interventional Radiology (IR) is occupying an increasingly prominent role in the care of patients with cancer, with involvement from initial diagnosis, right through to minimally invasive treatment of the malignancy and its complications. Adequate diagnostic samples can be obtained under image guidance by percutaneous biopsy and needle aspiration in an accurate and minimally invasive manner. IR techniques may be used to place central venous access devices with well-established safety and efficacy. Therapeutic applications of IR in the oncology patient include local tumour treatments such as transarterial chemo-embolisation and radiofrequency ablation, as well as management of complications of malignancy such as pain, organ obstruction, and venous thrombosis.

In vivo cell death mediated by synthetic ion channels

Synthetic ion channel hydraphiles, which are known to infiltrate membranes and disrupt ion homeostasis, were tested as direct injection toxins in live mice as potential schlerotic agents. The study uses a near-IR dye to image and evaluate the success of the approach.

Real-time magnetic resonance-guided microwave coagulation therapy for pelvic recurrence of rectal cancer: initial clinical experience using a 0.5 T open magnetic resonance system

PURPOSE

This study aims to evaluate consecutive cases of recurrent rectal cancer in the pelvic cavity treated with microwave coagulation therapy using real-time navigation by an open magnetic resonance system.

METHODS

Nine recurrent pelvic lesions in 8 patients after curative resection of rectal cancer were treated with real-time magnetic resonance-guided microwave coagulation therapy as a palliative local therapy to reduce tumor volume and/or local pain. Clinical and pathological data were collected retrospectively by reviewing medical records and clinical imaging results.

RESULTS

Seven patients received other treatments before real-time magnetic resonance-guided microwave coagulation. Six patients had distant synchronous metastases. Three patients underwent surgery under lumbar anesthesia. Microwave coagulation was performed percutaneously in 5 lesions and under laparotomy in 4 lesions. Although adverse events related to microwave coagulation (skin necrosis and nerve injury) were observed, no fatal complications occurred. Local re-recurrence was observed in 2 of 9 ablated lesions. Except for 1 patient who died of chronic renal failure, the remaining 7 patients died of cancer. Median overall survival after microwave coagulation for all patients was 10 months (range, 4-37 mo). Median overall survival after discovery of pelvic recurrence in all patients was 22 months (range, 9-42 mo).

CONCLUSIONS

The benefits of using an open magnetic resonance system in the pelvic cavity include the abilities to treat tumors that cannot be visualized by other modalities, to demonstrate internal architectural changes during treatment, to differentiate treated vs untreated areas, and to allow adjustments to the treatment plan during the procedure. Additional studies are required to clarify the efficacy of tumor coagulation for local control.

Microwaves create larger ablations than radiofrequency when controlled for power in ex vivo tissue

PURPOSE

To compare ablation zones created with equal amounts of 2.45 GHz microwave and 480 kHz radiofrequency (RF) energy in ex vivo liver and lung.

METHODS

A total of 38 ablations were performed in ex vivo liver and lung for 10 min each. Nineteen RF ablations (nine liver, ten lung) were performed with a 480 kHz system (200 W max, impedance-based pulsing) and cooled electrode while measuring the average RF power applied. Nineteen microwave ablations (nine liver, ten lung) were then created using a cooled triaxial antenna to deliver 2.45 GHz at the same power level as in RF experiments. Ablation zones were then sectioned and measured for minimum, maximum and mean diameters, and circularity. Measurements were compared using t-tests, with P < 0.05 indicating statistical significance.

RESULTS

Mean diameters of microwave ablations were greater than RF ablations in both liver and lung (4.4 +/- 0.3 vs 3.3 +/- 0.2 cm in liver; 2.45 +/- 0.3 vs 1.6 +/- 0.5 cm in lungs; P < 0.0005 all comparisons). There was no significant difference in the mean power applied during microwave or RF ablations in either organ (54.44 +/- 1.71 W vs 56.4 +/- 6.7 W in liver, P > 0.05; 40 +/- 0.95 W vs 44.9 +/- 7.1 W in lung, P > 0.05).

CONCLUSIONS

Using a single cooled applicator, microwave energy at 2.45 GHz produces larger ablations than an equivalent amount of 480 kHz RF energy in normal liver and lung. This was more apparent in lung, likely due to the high baseline impedance which limits RF, but not microwave power delivery.

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.

CT-guided radiofrequency ablation in the treatment of recurrent rectal cancer

OBJECTIVE

Locally recurrent rectal adenocarcinoma remains a therapeutic challenge that is unsatisfactorily managed by surgery and radiation therapy or chemotherapy. Palliative CT-guided radiofrequency ablation was used in 14 patients with recurrent rectal adenocarcinoma who had been previously treated with abdominoperineal resection and radiation therapy. Follow-up CT or MRI was performed at 3, 6, 12, and 24 months. Pain palliation was monitored by the brief pain inventory (BPI).

CONCLUSION

One month after radiofrequency ablation, 11 patients reported satisfactory BPI mean scores reduction compared to baseline (from 7.6 to 3.4 and from 5.1 to 1.6 for worst and average pain, respectively). In two unresponsive patients, retreatment was successfully performed at 3 months. After 24 months, worst and average pain scores further decreased (to 2.6 and 0.8, respectively) in 10 patients, who, at imaging, showed an ablation zone covering the entire original lesion in two patients and incomplete ablation in eight. In our experience, radiofrequency ablation is a safe and effective palliative treatment for patients with recurrent rectal adenocarcinoma.

Interventional radiology in the elderly

Interventional radiological percutaneous procedures are becoming all the more important in the curative or palliative management of elderly frail patients with multiple underlying comorbidities. They may serve either as alternative primary minimally invasive therapies or adjuncts to traditional surgical treatments. The present report provides a concise review of the most important interventional radiological procedures with a special focus on the treatment of the primary debilitating pathologies of the elderly population. The authors elaborate on the scientific evidence and latest developments of thermoablation of solid organ malignancies, palliative stent placement for gastrointestinal tract cancer, airway stenting for tracheobronchial strictures, endovascular management of aortic and peripheral arterial vascular disease, and cement stabilization of osteoporotic vertebral fractures. The added benefits of high technical and clinical success coupled with lower procedural mortality and morbidity are highlighted.

Transhepatic CT-guided radiofrequency ablation of adrenal metastases from hepatocellular carcinoma

The prognosis of patients with adrenal metastases from hepatocellular carcinoma (HCC) has been poor, and aggressive treatment of these tumors is mandatory to improve patients' survival. Since adrenalectomy may be difficult to perform after previous surgery of the right liver lobe, other approaches are required to treat the adrenal mass. This report aims at demonstrating the feasibility of CT-guided transhepatic radiofrequency ablation of right adrenal HCC metastases pretreated with chemoembolization in patients unable to undergo surgical resection.

Polymer Implants for Intratumoral Drug Delivery and Cancer Therapy

To address the need for minimally invasive treatment of unresectable tumors, intratumoral polymer implants have been developed to release a variety of chemotherapeutic agents for the locoregional therapy of cancer. These implants, also termed "polymer millirods," were designed to provide optimal drug release kinetics to improve drug delivery efficiency and antitumor efficacy when treating unresectable tumors. Modeling of drug transport properties in different tissue environments has provided theoretical insights on rational implant design, and several imaging techniques have been established to monitor the local drug concentrations surrounding these implants both ex vivo and in vivo. Preliminary antitumor efficacy and drug distribution studies in a rabbit liver tumor model have shown that these implants can restrict tumor growth in small animal tumors (diameter < 1 cm). In the future, new approaches, such as three-dimensional (3-D) drug distribution modeling and the use of multiple drug-releasing implants, will be used to extend the efficacy of these implants in treating larger tumors more similar to intractable human tumors.

Radiofrequency ablation of pulmonary tumours: current status

Radiofrequency ablation (RFA) for thoracic tumours has emerged as a minimally invasive therapy option for primary and secondary lung tumours and has gained increasing acceptance for pain palliation. The procedure is well tolerated and the complication rates are low. RFA provides the opportunity for localized tissue destruction of limited tumour volumes with medium and long term follow-up data suggesting that survival figures do parallel those of non-surgical treatment modalities. The purpose of this article is to review the status of RFA in lung tumours, to emphasize its place in symptomatic palliation and to discuss its potential role in conjunction with radiation or systemic therapy.

New horizons in MR-controlled and monitored radiofrequency ablation of liver tumours

There is a sustained interest in using magnetic resonance (MR) thermometry to monitor the radiofrequency ablation of liver tumours as a means of visualizing the progress of the thermal coagulation and deciding the optimal end-point. Despite numerous technical challenges, important progress has been made and demonstrated in animal studies. In addition to MR thermometry, MR can now be used for the guidance of the tumour targeting with ‘fluoroscopic’ rapid image acquisition, and it can provide several contrast mechanisms for post-procedural assessment of the extent of the thermal coagulation zone. Challenges of in vivo simultaneous MR thermometry implementation and the current limitations of the thermal dose model for the estimation of the extent of the thermal coagulation zone are discussed. MR imaging could enhance the success of RF ablation of liver tumours due to its potential to provide accurate targeting, monitoring, and post-procedural evaluation.

Percutaneous laser ablation of unresectable primary and metastatic adrenocortical carcinoma

PURPOSE

To evaluate the feasibility, safety, and clinical benefits of percutaneous laser ablation (PLA) in patients with unresectable primary and metastatic adrenocortical carcinoma (ACC).

PATIENTS AND METHODS

Four patients with hepatic metastases from ACC and a Cushing's syndrome underwent ultrasound-guided PLA. In one case the procedure was performed also on the primary tumor.

RESULTS

After three sessions of PLA, the primary tumor of 15 cm was ablated by 75%. After 1-4 (median 1) sessions of PLA, five liver metastases ranging from 2 to 5 cm were completely ablated, while the sixth tumor of 12 cm was ablated by 75%. There were no major complications. Treatment resulted in an improvement of performance status and a reduction of the daily dosage of mitotane in all patients. The three patients with liver metastases presented a marked decrease of 24-h urine cortisol levels, an improved control of hypertension and a mean weight loss of 2.8 kg. After a median follow-up after PLA of 27.0 months (range, 9-48 months), two patients have died of tumor progression, while two other patients remain alive and free of disease.

CONCLUSIONS

Percutaneous laser ablation is a feasible, safe and well tolerated procedure for the palliative treatment of unresectable primary and metastatic ACC. Further study is required to evaluate the impact of PLA on survival.

Improving outcomes in difficult bone cancers using multimodality therapy, including radiation: Physician and nursing perspectives

Principles of therapy are similar for Ewing's sarcoma and osteosarcoma. Chemotherapy or surgery alone cures few patients. Multimodality measures are needed for durable response. Quality of life and function are very important short- and long-term considerations. The spine, sacrum, pelvis, ankle, hand, mediastinum, pulmonary hilum, and chest wall are examples of bone cancer locations for which surgery is difficult. Patients with positive margins may need radiation and may experience systemic therapy delay, recurrence, loss of function, or any combination of these. When radiation is used as a means of local control, concomitant chemotherapy can increase its effectiveness. Options for difficult Ewing's sarcoma and osteosarcoma situations and multimodality solutions, including 1 mCi/kg of samarium and proton therapy, are discussed. Combination radiation and chemotherapy regimens are summarized, and organization of patients, caregivers, and medical teams for multimodality therapy is described, along with tools used in our institution that aid in this process.