Radiofrequency Ablation of Carcinoid and Sarcoma Liver Metastases

Abstract

The relative safety of radiofrequency ablation for malignant tumors has increased the indications for its use in the therapy of metastatic disease. Although tumor debulking has been considered inappropriate oncologic therapy in the past due to the associated complications and lack of clinical benefit, with safer techniques we are now able to determine if destroying most of the tumor mass in the liver can translate into improved palliation or even improved survival in patients with diseases considered inoperable in the past. Radiofrequency Ablation (RFA) of Hepatic Metastases from Carcinoid TumorsCarcinoid tumors belong to the family of neuroendocrine tumors and are the most frequent gastrointestinal endocrine tumors (55%). They are still relatively rare, representing only 10% of small bowel tumors and 2% of all gastrointestinal malignancies. 1,2 The overall incidence is reported to be between 1 and 2/100,000 per year. 3-5 Carcinoid tumors have traditionally been classified according to their embryologic derivation. Foregut carcinoids comprise 20% of all carcinoid tumors and include thymic, lung, gastric, and duodenal tumors. Hindgut carcinoids constitute 15% of all carcinoid tumors and commonly originate from the colon 107 7 or rectum. Midgut carcinoids arise from the small bowel, appendix, and proximal colon, and make up 40% of carcinoid tumors. 4,5 The most common gastrointestinal site of origin is the appendix, followed by the small intestine and rectum. Carcinoid tumors produce a variety of biologically active hormones depending on their site of origin. The best characterized of these substances is serotonin, but they have also been found to produce and secrete adrenocorticotropic hormone (ACTH), gastrin, histamine, dopamine, substance P, chromogranin A, neurotensin, prostaglandins, and others. 4,5 Although generally indolent in their growth and progression, carcinoid tumors are the most frequent neuroendocrine tumors to metastasize to the liver. 6 In fact a majority of patients present with disseminated disease and involvement of the liver at the time of diagnosis. These patients usually have primary and metastatic carcinoid tumors that remain asymptomatic until their hepatic tumor burden overtakes the liver's ability to metabolize active hormones produced by these tumors, resulting in carcinoid syndrome. This severe endocrinopathy is characterized by flushing, diarrhea, cardiac valvular damage, bronchoconstriction, and asthma. 2,4,5,7 The incidence of carcinoid syndrome, caused by metastases to the liver is about 0.5/100,000, and most are associated with primary tumors of the small intestine. 8 Patients in whom metastatic disease is suspected should be evaluated by abdominal imaging, including ultrasound, computed tomography (CT), CT-angioportography, magnetic resonance imaging (MRI), or octreotide scintigraphy to rule out liver metastases. 1 Liver function tests are usually unreliable for screening for metastasis, as they are only elevated when there is a large burden of tumor in the liver. 5 Carcinoid met...

Grenzen und Perspektiven ablativer Verfahren bei Lebertumoren

“…Durchmesser von etwa 5 cm sicher zu behandeln. Gröûere Tumoren weisen auch bei repetitiver Therapie ein erhebliches Risiko für eine inkomplette Ablation auf und zeigen entsprechend hohe Lokalrezidivraten [1,8,16,22,26,28,37,49]. Gleiches gilt für eine groûe Anzahl von Lebertumoren.…”

“…Zwar berichten einige kleinere Studien über die Durchführung von Ablationen bei diffusem hepatischem Tumorbefall. Aussagen über das Langzeitüberleben sind in diesen Studien nicht zu erhalten [1,8,16,22,26,28,37,49]. Hinsichtlich der Lokalisation des Lebertumors gilt, dass prinzipiell jeder Tumor, der durch einen Applikator erreichbar ist, auch lokal behandelt werden kann.…”