Radiofrequency ablation of neuroendocrine liver metastases

Interventional Radiology Approaches for Liver Metastases from Thyroid Cancer: A Case Series and Overview of the Literature

Background

Liver metastases (LMs) from thyroid cancer (TC) are relatively uncommon in clinical practice and their management is challenging. Interventional radiology loco-regional treatments (LRTs), including radiofrequency ablation (RFA) and trans-arterial chemoembolization (TACE), have been successfully employed to treat LMs from various types of cancer.

Methods

We analyzed the role of LRTs in the management of unresectable LMs from differentiated and medullary TCs performed at our institution from 2015 to 2020. A review of the available English literature regarding this topic was also performed.

Results

Six hepatic LRTs were performed in 4 TC patients with LMs, in 2 cases after the start of treatment with a tyrosine kinase inhibitor (TKI). A partial response was obtained in 2 patients; the diameter of the largest targeted lesion was 18 mm in both of them. The remaining procedures were performed on larger lesions and a stable disease was achieved in all but one case. Acute LRT-related complications were transient and mild. In literature, the largest studies were focused on TACE in LMs from MTC, showing good tolerance and remarkable disease control, especially in case of limited liver tumour involvement.

Conclusion

LRTs for LMs represent a valuable option for the treatment of metastatic TC in case of isolated hepatic progression or for symptoms relief, also after the start of TKI treatment as part of a multimodal approach. The best disease control is obtained when hepatic metastatic burden is limited. These procedures are generally well tolerated; however, a cautious multidisciplinary selection of the candidates is mandatory.

A literature-based treatment algorithm for low-grade neuroendocrine liver metastases

BACKGROUND

The optimal timing of treatment of liver metastases from low-grade neuroendocrine tumors (LG-NELM) varies significantly due to numerous treatment modalities and the literature supporting various treatment(s). This study sought to create and validate a literature-based treatment algorithm for LG-NELM.

METHODS

A treatment algorithm to maximize overall survival (OS) was designed using peer-reviewed articles evaluating treatment of LG-NELM. This algorithm was retrospectively applied to patients treated for LG-NELM at our institution. Deviation was determined based on whether or not a patient received treatment consistent with that recommended by the algorithm. Patients who did and did not deviate from the algorithm were compared with respect to OS and number of treatments.

RESULTS

Applying our algorithm to a 149-patient cohort, 57 (38%) deviated from recommended treatment. Deviation occurred in the form of alternative (28, 49%) versus additional procedures (29, 51%). Algorithm deviators underwent significantly more procedures than non-deviators (median 1 vs. 2, p < 0.001). Cox model indicated no difference in OS associated with algorithm deviation (HR 1.19, p = 0.58) when controlling for age and tumor characteristics.

CONCLUSION

This literature-based algorithm helps standardize treatment protocols in patients with LG-NELM and can reduce cost and risk by minimizing unnecessary procedures. Prospective implementation and validation is required.

Liver-directed therapies for liver metastases from neuroendocrine neoplasms: Can laser ablation play any role?

Aggressive cytoreduction can prolong survival in patients with unresectable liver metastases (LM) from neuroendocrine neoplasms (NEN), and minimally invasive, liver-directed therapies are gaining increasing interest. Catheter-based treatments are used in disseminated disease, whereas ablation techniques are usually indicated when the number of LM is limited. Although radiofrequency ablation (RFA) is by far the most used ablative technique, the goal of this opinion review is to explore the potential role of laser ablation (LA) in the treatment of LM from NEN. LA uses thinner needles than RFA, and this is an advantage when the tumors are in at-risk locations. Moreover, the multi-fiber technique enables the use of one to four laser fibers at once, and each fiber provides an almost spherical thermal lesion of 12-15 mm in diameter. Such a characteristic enables to tailor the size of each thermal lesion to the size of each tumor, sparing the liver parenchyma more than any other liver-directed therapy, and allowing for repeated treatments with low risk of liver failure. A recent retrospective study reporting the largest series of LM treated with LA documents both safety and effectiveness of LA, that can play a useful role in the multimodality approach to LM from NEN.

Percutaneous Laser Ablation of Liver Metastases from Neuroendocrine Neoplasm. A Retrospective Study for Safety and Effectiveness

PURPOSE

To retrospectively assess safety and efficacy of laser ablation (LA) of multiple liver metastases (LM) from neuroendocrine neoplasms (NEN).

METHODS

Twenty-one patients with NEN and at least 3 LM ≤ 4 cm in diameter underwent ultrasonography-guided LA. Up to seven LM were ablated in a single session; if the number of LM exceeded seven, the remaining LM were ablated in further LA sessions with a time interval of 3-4 weeks. LA was performed according to the multifiber technique. The patients underwent contrast-enhanced CT 1 month after LA, and were subsequently monitored every 3 months for the first 2 years and then every 6 months.

RESULTS

In total, 189 LM were treated in 21 patients (mean 9 ± 8.2, median 6) in 41 LA sessions (range 1-5). The diameter of LM ranged from 5 to 35 mm (median 19 mm, mean 17.9 ± 6.4 mm). One grade 4 complication occurred (0.53%): a bowel perforation managed by surgery. Technical efficacy was 100%, primary efficacy rate 94.7%, and secondary efficacy rate 100%. Complete relief of hormone-related symptoms was obtained in all the 13 symptomatic patients. Median follow-up was 39 months (range 12-99). 1-, 2-, 3-, and 5-year survival rates were 95%, 86%, 66%, and 40%, respectively. Overall survival resulted higher for patients with Ki-67 expression ≤ 7% than for those with Ki-67 > 7% (p = 0.0347).

CONCLUSIONS

LA is a promising and safe technique to treat LM from NEN. A longer follow-up should provide definitive information on the long-term efficacy of this liver-directed therapy.

LEVEL OF EVIDENCE

Retrospective study, local non-random sample, level 3.

Gastroenteropancreatic neuroendocrine tumors: recommendations of Turkish multidisciplinary neuroendocrine tumor study group on diagnosis, treatment and follow-up

Gastroenteropancreatic neuroendocrine tumors (GEPNETs) are a relatively rare, heterogeneous group of diseases in which important advances have been observed in the diagnosis and treatment as well as in our understanding of the biology and genetics of the disease in recent years. Given the insufficient scientific data available on evidence-based management of GEPNETs and the differences in circumstances in individual countries, a multidisciplinary study group was established to provide guidelines for the management of GEPNETS. This study group consisted of a medical oncologist, endocrinologist, surgeon, pathologist, gastroenterologist, and a nuclear medicine specialist, who aimed to prepare a practical guide in the light of existing scientific data and international guidelines, to be used in common clinical practice.

Switching Monopolar Radiofrequency Ablation Using a Separable Cluster Electrode in Patients with Hepatocellular Carcinoma: A Prospective Study

OBJECTIVE

This study was conducted to evaluate the outcomes of multi-channel switching RFA using a separable cluster electrode in patients with HCC.

METHODS

From November 2011 to July 2013, 79 patients with 98 HCCs < 5 cm were enrolled and treated with RFA using a multi-channel switching radiofrequency system and a separable cluster electrode under the guidance of a real-time fusion imaging system. The primary and secondary endpoints were the 3-year local tumor progression (LTP) rate and recurrence-free survival (RFS) rate, respectively. For post hoc analyses, LTP, RFS, and major complication rates were retrospectively compared with a historical control group treated with RFA using the same radiofrequency system but with multiple internally-cooled electrodes.

RESULTS

The technique success rate of the 98 tumors was 100%. Cumulative 1-year, 2-year, and 3-year LTP rates were 3.4%, 6.9%, and 12.4%, respectively. For patient-level data, cumulative 1-year, 2-year, and 3-year RFS rates were 83.9%, 68.6%, and 45.4%, respectively. On post hoc analyses, none of the baseline characteristics showed a significant difference between the separable cluster electrode and multiple internally-cooled electrodes group. Cumulative LTP and RFS rates of the two groups also showed no significant difference (p = 0.401 and p = 0.881, respectively). Finally, major complication rates of the separable cluster electrode group (5.0%, 4/79) and multiple internally-cooled electrodes group (5.9%, 4/74) were also comparable (p = 1.000).

CONCLUSION

Switching monopolar RFA using a separable cluster electrode is a feasible and efficient technique for the treatment of HCCs smaller than 5 cm, providing comparable local tumor control to multiple internally-cooled electrodes.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02745483.

Pancreatic neuroendocrine tumors: Challenges in an underestimated disease

Pancreatic neuroendocrine tumours (PanNETs) are considered a relatively unusual oncologic entity. Due to its relative good prognosis, surgery remains the goal standard therapy not only in localized disease but also in the setting of locally or metastatic disease. Most of the patients are diagnosed in metastatic scenario, where multidisciplinary approach based on surgery, chemotherapies, liver-directed and/or molecular targeted therapies are commonly used. Owing to a deeper molecular knowledge of this disease, these targeted therapies are nowadays widely implemented, being the likely discovery of predictive biomarkers that would allow its use in other settings. This review is focused on describing the different classifications, etiology, prognostic biomarkers and multidisciplinary approaches that are typically used in PanNET.

Ablation techniques for primary and metastatic liver tumors

Ablative treatment methods have emerged as safe and effective therapies for patients with primary and secondary liver tumors who are not surgical candidates at the time of diagnosis. This article reviews the current literature and describes the techniques, complications and results for radiofrequency ablation, microwave ablation, cryoablation, and irreversible electroporation.

Radiofrequency ablation for neuroendocrine liver metastases: a systematic review

To determine the efficacy of radiofrequency (RF) ablation in neuroendocrine tumor (NET) liver metastases. A systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Eight studies were included (N = 301). Twenty-six percent of RF ablation procedures were percutaneous (n = 156), with the remainder conducted at surgery. Forty-eight percent of patients had a concomitant liver resection. Fifty-four percent of patients presented with symptoms, with 92% reporting symptom improvement following RF ablation (alone or in combination with surgery). The median duration of symptom improvement was 14-27 months. However, recurrence was common (63%-87%). RF ablation can provide symptomatic relief in NET liver metastases alone or in combination with surgery.

Liver-directed therapy for neuroendocrine liver metastases

Abstract: 

Neuroendocrine tumors are relatively uncommon neoplasms presenting with a wide spectrum of clinical behavior. Many patients may present with or develop liver metastases from neuroendocrine tumors, which significantly influences prognosis and the potential for symptoms. Data suggest that some patients may have symptomatic relief and oncologic benefit from liver-directed therapy for neuroendocrine tumor metastases. Surgical resection, tumor ablation, transarterial therapy such as bland embolization, chemoembolization and radioembolization, as well as liver transplantation have been studied as liver-directed therapies. Data continue to emerge to help guide selection of treatment modality for an individual patient. The spectrum of behavior of neuroendocrine metastases and heterogeneity in the literature are a challenge to arriving at cohesive recommendations for all patients.

Update on pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (pNETs) are relatively rare tumors comprising 1-2% of all pancreas neoplasms. In the last 10 years our understanding of this disease has increased dramatically allowing for advancements in the treatment of pNETs. Surgical excision remains the primary therapy for localized tumors and only potential for cure. New surgical techniques using laparoscopic approaches to complex pancreatic resections are a major advancement in surgical therapy and increasingly possible. With early detection being less common, most patients present with metastatic disease. Management of these patients requires multidisciplinary care combining the best of surgery, chemotherapy and other targeted therapies. In addition to surgical advances, recently, there have been significant advances in systemic therapy and targeted molecular therapy.

Transplantation and surgical strategies in patients with neuroendocrine liver metastases: protocol of four systematic reviews

Background

Hepatic metastases of neuroendocrine tumors (NETs) are considered a major prognostic factor associated with significantly reduced survival compared to patients without liver metastases. Several surgical and nonsurgical strategies are present to treat resectable and nonresectable liver metastases, some of which have the potential to cure liver mestatases.

Objective

The aims of the four systematic reviews presented in the paper are to determine the effectiveness of liver resection versus nonsurgical treatment of patients with NET liver metastases, to investigate the impact of neoadjuvant and adjuvant treatment options on the tumor-free survival, to assess the role of liver transplantation in patients presenting with unresectable bilateral hepatic metastases, and to evaluate the role of primary tumor resection in presence of unresectable liver metastases.

Methods

Literature search was performed on Medical Literature Analysis and Retrieval System Online, Excerpta Medica Database, and the Cochrane Library (Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials). No language restrictions were applied. Randomized controlled trials, prospective and retrospective comparative cohort studies, and case-control studies will be used for the qualitative and quantitative synthesis of the systematic reviews. Case series will be only included in a separate database for descriptive purposes.

Results

This study is ongoing and presents a protocol system of four systematic reviews that will assist in determining the effectiveness of liver resection versus nonsurgical treatment of patients with NET liver metastases. This study is also assumed to investigate the impact of neoadjuvant and adjuvant treatment options on the tumor-free survival, the role of liver transplantation, and the relevance of primary tumor resection in presence of unresectable liver metastasis.

Conclusions

The systematic reviews will show the current evidence based on the effectiveness of surgical strategies in patients with NET liver metastases and serve as basis for clinical practice guidelines.

Trial Registration

The systematic reviews have been prospectively registered with the International Prospective Register of Systematic Reviews: liver resection (CRD42012002652); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002652 (Archived by WebCite at http://www.webcitation.org/6LQUqMnqL,). neoadjuvant and adjuvant treatment strategies (CRD42012002656); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002656 (Archived by WebCite at http://www.webcitation.org/6LQVvEHuf). liver transplantation (CRD42012002655); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002655 (Archived by WebCite at http://www.webcitation.org/6LQW7WFo3,). resection of the locoregional primary NET (CRD42012002654); http://www.crd.york.ac.uk/prospero/display_record.asp?ID=CRD42012002654 (Archived by WebCite at http://www.webcitation.org/6LQWEIuGe).

Outcome after resection and radiofrequency ablation of liver metastases from small intestinal neuroendocrine tumours

BACKGROUND

In patients with small intestinal neuroendocrine tumour (SI-NET), liver resection or radiofrequency ablation (RFA) of liver metastases is performed for palliation of carcinoid syndrome, and in an effort to improve survival. Data are generally reported from case series, and no randomized trials have studied these treatments. The aim was to compare outcome after liver resection and/or RFA with that of non-surgical treatment in patients with liver metastases from SI-NET.

METHODS

The study included patients with liver metastases from SI-NET who underwent liver RFA/resection or were treated non-surgically. A propensity score match was performed to reduce bias between groups, using baseline variables such as the Charlson co-morbidity index, age, symptoms, carcinoid heart disease, extent of metastases and proliferation index.

RESULTS

Some 103 patients who had RFA and/or liver resection were compared with 273 controls. Propensity score matching resulted in two matched groups, each of 72 patients, with no significant differences in baseline variables. The matched resection/RFA and control groups showed no difference in overall survival (both 74 per cent at 5 years; P = 0·869) or disease-specific survival (74 versus 78 per cent respectively at 5 years; P = 1·000). However, urinary 5-hydroxyindoleacetic acid levels were lower (median 77 versus 120 µmol per 24 h; P = 0·005) and the proportion of patients with progressive disease within the liver was smaller (2 of 18 versus 8 of 18; P < 0·001) in the resection/RFA group after 5 years.

CONCLUSION

These data do not support the use of liver resection and/or RFA in an effort to prolong survival in patients with liver metastases from SI-NET.

Liver-directed therapy for neuroendocrine neoplasm hepatic metastasis prolongs survival following progression after initial surgery

BACKGROUND

Surgery confers the best chance of long-term survival in patients with neuroendocrine neoplasm hepatic metastases (NENHM). Disease progression invariably occurs in the majority of patients. No previous study has addressed the outcomes after treatment of hepatic disease progression in patients who initially underwent surgical extirpation of NENHM. This was the principal aim of the current study.

METHODS

Seventy-four patients with NENHM underwent surgery for NENHM between December 1992 and December 2009. Of these, 50 patients developed disease progression in the liver. These patients were then treated with specific liver-directed therapies according to consensus of a multidisciplinary team. The current study evaluates progression-free survival (PFS) and overall survival (OS) following treatment of hepatic disease progression with specific liver-directed therapies.

RESULTS

No patient was lost to follow up. The median follow-up after treatment of progression was 29 months (range = 2-137). The median PFS and OS after diagnosis of disease progression were 15 and 48 months, respectively. Specific liver-directed therapies included surgery in 10 patients, radioembolization in 15, cytotoxic chemotherapy in 14, and conservative therapy in 11. Four independent factors associated with PFS and OS were identified through a multivariate analysis. These were initial progression-free survival (PFS, P = 0.006, HR= 0.32), extra-hepatic disease (OS, P = 0.029, HR = 4.04; PFS, P = 0.004, HR = 4.03), histological grade (PFS, P = 0.006, HR = 4.08), and type of secondary intervention (PFS, P = 0.024, HR = 0.63).

CONCLUSION

A multimodality approach towards treatment of disease progression as shown in this study that includes repeat surgery or radioembolization has been shown to achieve a superior outcome in the setting of disease progression/recurrence.

Percutaneous radiofrequency thermal ablation of primary and metastatic hepatic tumors: current concepts and review of the literature

The liver is a common site for primary malignancy and hematogenous metastasis. Although surgical resection of primary or metastatic hepatic tumors is generally regarded as first-line therapy, the majority of patients with hepatic malignancy have disease that is not amenable to surgical resection because of tumor location, poor hepatic reserve, or medical comorbidities. This has led to significant interest in the development of nonsurgical image-guided therapies, including radiofrequency ablation (RFA). RFA is appealing as a minimally invasive therapy that may be performed on an outpatient basis. It enables ablation of an area 3 to 5 cm in diameter, with relatively low morbidity and mortality rates. The results concerning the use of percutaneous RFA in the treatment of hepatocellular carcinoma, colorectal metastases, and other hepatic metastases are reviewed in this article. Clinical and technical considerations and complications are also discussed.

Evolving diagnostic and treatment strategies for pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (NET) have diverse clinical presentations. Patients with symptoms of hormone secretion may require specific medical interventions to control those symptoms prior to antitumor intervention. In some patients, tumors in the pancreas may be occult and specialized diagnostic imaging or surgery may be required for diagnosis. Other patients may present with more advanced disease, presenting with symptoms of tumor bulk rather than hormone secretion. Treatment options for patients with advanced pancreatic neuroendocrine tumors include surgical resection and hepatic directed therapies, including partial hepatectomy, hepatic artery embolization, or other ablative techniques. Streptozocin or temozolomide-based chemotherapy regimens are active against pancreatic NET, and can also play an important role in the palliation of patients with advanced disease. A number of biologically targeted agents targeting the VEGF and mTOR signaling pathways have recently shown promise, with recent trials showing treatment with the VEGFR tyrosine kinase inhibitor sunitinib or the mTOR inhibitor everolimus improves progression-free survival in patients with advanced NET.

NANETS treatment guidelines: well-differentiated neuroendocrine tumors of the stomach and pancreas

Well-differentiated neuroendocrine tumors (NETs) of the stomach and pancreas represent 2 major subtypes of gastrointestinal NETs. Historically, there has been little consensus on the classification and management of patients with these tumor subtypes. We provide an overview of well-differentiated NETs of the stomach and pancreas and describe consensus guidelines for the treatment of patients with these malignancies.

Thermal ablative therapies for secondary hepatic malignancies

Hepatic metastatic disease affects more than half of the patients with colorectal cancer and neuroendocrine cancer. Hepatic resection remains the gold standard for liver metastasis from colorectal and neuroendocrine primaries. Thermal ablative technologies, however, are increasingly being used either alone or in combination with resection to treat this group of patients. Radiofrequency ablation is the most common modality used in the United States, whereas microwave ablation has been more widely used in the East. In addition to being adjuncts to hepatic resection, ablation has gained an increased popularity in the management of patients who are not operative candidates or have unresectable colorectal or neuroendocrine hepatic metastasis. Although radiofrequency ablation seems to have a higher local recurrence than resection, ablation remains an important therapeutic option for many patients with hepatic metastasis.

Neuroendocrine liver metastases

This review summarizes regional strategies for management of neuroendocrine liver metastases (NLM), including hepatic resection, ablation, liver transplantation, and hepatic arterial embolization/chemoembolization. Despite early disease recurrence and/or progression, resection of NLM with or without combined ablation provides long-term survival and symptom improvement. When complete resection of gross liver disease is not feasible, resection as a tumor debulking strategy should be considered in patients with extreme hormonal symptoms refractory to other treatments or with tumors in locations that would affect short-term quality of life. Hepatic arterial embolization with or without local instillation of chemotherapy may induce disease response, symptomatic improvement, and prolonged survival in patients with unresectable NLM. Early disease recurrence, high postoperative mortality, the absence of extensive experience, and lack of universal indications for organ allocation preclude orthotopic liver transplantation as an option for most patients with unresectable NLM.

Liver metastases of neuroendocrine tumors: treatment with hepatic transarterial chemotherapy using two therapeutic protocols

OBJECTIVE

The objective of our study was to retrospectively determine the effectiveness of hepatic transarterial chemotherapy using two therapeutic protocols-mitomycin C alone and combined mitomycin C and gemcitabine-on local tumor control and survival rate in patients with liver metastases from neuroendocrine tumors.

MATERIALS AND METHODS

This article describes a retrospective study of 48 patients (age range, 37-77 years; mean age, 61.1 years; SD, 10.3) with liver metastases from neuroendocrine tumors who underwent repetitive selective hepatic artery chemotherapy using mitomycin C alone (group 1, n = 18 patients who underwent 182 therapeutic sessions; mean, 10.11 sessions per patient) and combined mitomycin C and gemcitabine chemotherapy agents (group 2, n = 30 patients who underwent 312 therapeutic sessions; mean, 10.4 sessions per patient) with 4-week intervals between treatment sessions.

RESULTS

Both treatment protocols were well tolerated by all patients. Only minor side effects occurred in both groups, and no major complications developed. Local tumor control evaluation according to the Response Evaluation Criteria in Solid Tumors (RECIST) revealed the following for group 1: partial response, 11.1%; stable disease, 50%; and progressive disease, 38.9%. RECIST criteria for group 2 indicated partial response in 23.33%, stable disease in 53.34%, and progressive disease in 23.33%. The survival rate from the initial diagnosis to the fifth year for group 1 was 11.11% and for group 2, 46.67%. The median survival time from the initial diagnosis of group 1 was 38.67 months, whereas in group 2 it was 57.1 months.

CONCLUSION

Transarterial hepatic chemotherapy using mitomycin C and gemcitabine can be an effective therapeutic protocol for controlling local metastases and improving survival time in patients with hepatic metastases from neuroendocrine tumors.

The sonographer's role in RFA therapy of liver lesions

Interventional techniques using ultrasound guidance, such as Radio Frequency Ablation (RFA) of liver lesions, are the domain of the radiologist. However, real time ultrasound imaging as performed by the sonographer, is critical in monitoring the successful insertion and placement of the RFA needle. RFA is used to create a localised and controlled application of heat in order to induce necrosis of cells within the liver lesions.

The role of the sonographer is to assist in establishing the criteria for RFA therapy. This includes assessing the liver to establish how easily the lesion can be identified; the size of the lesion; its proximity to large blood vessels and adjacent vital organs and the access route to the lesion itself. In essence, in this discussion, the focus will be on the sonographic techniques in the assessment of the liver prior to RFA and the RFA procedure itself. A brief review of the clinical role that can be provided by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) is also included.

Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors

Pancreatic endocrine tumors (PETs) have long fascinated clinicians and investigators despite their relative rarity. Their clinical presentation varies depending on whether the tumor is functional or not, and also according to the specific hormonal syndrome produced. Tumors may be sporadic or inherited, but little is known about their molecular pathology, especially the sporadic forms. Chromogranin A appears to be the most useful serum marker for diagnosis, staging, and monitoring. Initially, therapy should be directed at the hormonal syndrome because this has the major initial impact on the patient's health. Most PETs are relatively indolent but ultimately malignant, except for insulinomas, which predominantly are benign. Surgery is the only modality that offers the possibility of cure, although it generally is noncurative in patients with Zollinger-Ellison syndrome or nonfunctional PETs with multiple endocrine neoplasia-type 1. Preoperative staging of disease extent is necessary to determine the likelihood of complete resection although debulking surgery often is believed to be useful in patients with unresectable tumors. Once metastatic, biotherapy is usually the first modality used because it generally is well tolerated. Systemic or regional therapies generally are reserved until symptoms occur or tumor growth is rapid. Recently, a number of newer agents, as well as receptor-directed radiotherapy, are being evaluated for patients with advanced disease. This review addresses a number of recent advances regarding the molecular pathology, diagnosis, localization, and management of PETs including discussion of peptide-receptor radionuclide therapy and other novel antitumor approaches. We conclude with a discussion of future directions and unsettled problems in the field.

Radiofrequency ablation of hepatic metastases from thyroid carcinoma

BACKGROUND

Radiofrequency ablation (RFA) is performed for various types of liver tumors. It might also have a role in the palliative treatment of liver metastases from thyroid carcinoma.

SUMMARY

Three patients with liver metastases of thyroid carcinoma were retrieved from our database of 125 patients who had been treated with RFA for liver tumors. In all three patients, the metastases were a sign of widespread disease, and several other treatment modalities had been performed earlier. Two patients had metastases from medullary thyroid carcinoma and had severe diarrhea. The third patient had a rapidly progressive metastasis of a follicular thyroid carcinoma. The aim of the treatment was cytoreduction with amelioration of symptoms (n = 2) and debulking with increased sensitivity for subsequent (131)I treatment. The ablation was performed via laparotomy (n = 1), laparoscopically (n = 1), or percutaneously (n = 1). One patient experienced superficial burn wounds after a long-lasting RFA procedure. Severity of symptoms was reduced significantly after RFA for a prolonged period of time. RFA induced partial tumor necrosis because of hypervascularization of the tumor in one patient. After arterial embolization the second RFA treatment induced total tumor necrosis. Local recurrences at the site of the ablated liver metastases were not encountered during follow-up.

CONCLUSIONS

RFA is a useful treatment modality in patients with liver metastases from thyroid carcinoma. It should be considered an adjunct to other types of treatment or for those patients in whom more regular treatment modalities are not effective or possible or are associated with increased risks.

Liver metastases of neuroendocrine carcinomas: interventional treatment via transarterial embolization, chemoembolization and thermal ablation

The aim of this review article is to provide a practical clinical guideline for indication, technical aspects, protocol guideline and strategies for the interventional treatment of liver metastases from neuroendocrine tumors and focusing on the results of various protocols of management. The response to therapy, in the published articles, is calculated on the basis of the following clinical parameters; including symptomatic response (SR), biologic response (BR), morphological response (MR), progress free survival (PFS), and survival periods (SP). Transarterial chemoembolization (TACE) has been associated with SR rates of 60-95%, BR of 50-90%, MR of 33-80%, SR of 20-80 months, and a 5-year survival of between 50% and 65%. PFS was also between 18 and 24 months. In the transarterial embolization (TAE) group, SR was similar to the TACE group, MR was 32% and 82%, survival was between 18 and 88 months with a survival rate of 40-67%, and BR was between 50% and 69%. Radiofrequency ablation (RFA), either percutaneous or during surgery, has been associated with SR of 71-95% for a mean duration of 8-10 months, BR of 65%, and mean SP of 1.6 years after ablation. The mean survival following surgical resection for operable cases is 4.26 years+/-S.D.: 1.1.

CONCLUSION

The interventional protocols for the management of liver metastases from neuroendocrine tumors: for oligonodular liver metastatic deposits, local resection or RFA and/or LITT is recommended, while in multinodular diseases with higher tumor load, TACE or TAE is recommended.

Techniques of interventional tumor therapy

INTRODUCTION

The last few years have seen the rapid development of new image-guided interventions for the local treatment of malignant tumors. The goal of this article is to provide an overview of the techniques that are most commonly used today in interventional oncology.

METHODS

Selective literature review on the current state of image-guided interventional techniques for local tumor therapy.

RESULTS

While surgery, radiation oncology, and systemic chemotherapy are still the three main pillars of tumor therapy, a broad range of minimally invasive, image-guided techniques for local tumor treatment is now available. These may be categorized as percutaneous injection of a toxic substance, transarterial embolization, thermal ablation, and internal radiotherapy. The choice of treatment depends on the type, location, and size of tumor. The greatest amount of clinical experience to date has been gathered in the treatment of primary and secondary hepatic malignancy, but there are interventional treatment options for virtually all regions of the body. At present, the utility of this form of treatment is limited for very large or multiple tumors; novel therapeutic options for these situations are now being studied.

DISCUSSION

The outcome of treatment depends on a judicious determination of the indication for it. The indication should be established by interdisciplinary consensus after all treatment options have been considered.

Brachytherapy of liver metastases

Brachytherapy for the treatment of liver metastases is a novel approach. In this procedure, techniques of locally ablative treatment in interventional radiology and radiation therapy are combined. After computed tomography (CT)-guided percutaneous implantation of catheters into the hepatic tumor, the irradiation is performed in an afterloading technique. This minimally invasive procedure offers circumscriptive high-dose rate irradiation of the lesion to treat in a single session, irrespective of breathing motion or potential cooling effects of neighboring vessels. Good local control rates have been achieved in several tumor entities, including both secondary and primary malignancies of the liver. This article gives an overview of the application technique, possible adverse events, and outcome with special attention to the pancreatic cancer scenario.

Current status of sonographically guided radiofrequency ablation techniques

OBJECTIVE

The purpose of this article was to review the current clinical applications of sonographically guided radiofrequency ablation (RFA) techniques.

METHODS

Publications regarding RFA extracted from a computerized database (MEDLINE) and from references cited in these articles were reviewed to evaluate the clinical effect and patient outcome.

RESULTS

Radiofrequency ablation has shown some promising effects in the treatment of tumors in various parts of the body. The recent advances in RFA technology enable larger volumes of treatment and make RFA clinically practical. It is most often used for hepatic and renal tumors, and applications for other organs and structures are increasing and rapidly developing. Sonography provides a convenient way to guide and monitor the procedure in most situations.

CONCLUSIONS

Effectiveness of RFA in the treatment of tumors in various body parts has been achieved. Radiofrequency ablation should be considered as an alternative or complementary method in the integration of oncologic management to obtain the greatest benefit to patients.