Thermoablative Techniques Research Articles

Current role of image-guided ablative therapies in lung cancer

Lung cancer is the leading cause of cancer-related mortality in the USA. Until recently, lung cancer treatment options (dependent upon the tumor grading and staging at presentation, and patient comorbidities) included surgical resection (lobar or sublobar), chemotherapy and external-beam radiation therapy. While these options are still viewed as the primary standard of care, newer minimally invasive percutaneous ablative techniques such as radiofrequency ablation, microwave ablation and cryoablation are currently being examined as treatment alternatives, especially in the setting of the nonsurgical candidate. This review will focus on these three distinct thermoablative techniques in the percutaneous setting of lung cancer treatment.

Focused ultrasound treatment of uterine fibroid tumors: Safety and feasibility of a noninvasive thermoablative technique

Objective: The purpose of this study was to determine the safety and efficacy of focused ultrasound surgery with magnetic resonance imaging guidance for the noninvasive treatment of uterine leiomyomas. Study Design: Fifty-five women with clinically significant uterine leiomyomas were treated. Pain and complications were assessed prospectively, and posttreatment magnetic resonance imaging was used to measure the treatment effects. Patients in three of the five centers underwent planned hysterectomy after treatment, which provided pathologic correlation of treatment. Results: Seventy-six percent of the enrolled patients completed the full treatment session. All treatments were conducted in an outpatient setting with minimal discomfort for subjects and no major complications. Pathologic examination of the uterus confirmed that magnetic resonance imaging guidance provides the safe and accurate delivery of effective levels of thermal energy with a 3-fold increase in volume of histologically documented necrosis, compared with treatment volume (6.6 ± 0.8 vs 18.4 ± 3.9 mL, P <.005). Conclusion: Magnetic resonance imaging-guided focused ultrasound surgery appears to be a well-tolerated treatment for uterine leiomyomas. (Am J Obstet Gynecol 2003;189:48-54.)

Locoregional therapies for hepatocellular carcinoma: a critical review from the surgeon's perspective.

This article reviews the current results of various locoregional therapies for hepatocellular carcinoma (HCC), with special reference to the implications for surgeons. Resection or transplantation is the treatment of choice for HCC, but most patients are not suitable candidates. The past decade has witnessed the development of a variety of locoregional therapies for HCC. Surgeons are faced with the challenge of adopting these therapies in the management of patients with resectable or unresectable HCC. A review of relevant English-language articles was undertaken based on a Medline search from January 1990 to August 2001. Retrospective studies suggested that transarterial chemoembolization is an effective treatment for inoperable HCC, but its perceived benefit for survival has not been substantiated in randomized trials, presumably because its antitumor effect is offset by its adverse effect on liver function. Nonetheless, it remains a widely used palliative treatment for HCC not amenable to resection or ablative therapies, and it also plays an important role as a treatment of postresection recurrence and as a pretransplant therapy for transplantable HCC. Better patient selection, selective segmental chemoembolization, and treatment repetition tailored to tumor response and patient tolerance may improve its benefit-risk ratio. Transarterial radiotherapy is a less available alternative that produces results similar to those of chemoembolization. Percutaneous ethanol injection has gained wide acceptance as a safe and effective treatment for HCCs 3 cm or smaller. Uncertainty in tumor necrosis limits its potential as a curative treatment, but its repeatability allows treatment of recurrence after ablation or resection of HCC that is crucial to prolongation of survival. Cryotherapy affords a better chance of cure because of predictable necrosis even for HCCs larger than 3 cm, but its use is limited by a high complication rate. There has been recent enthusiasm for heat ablation by microwave, radiofrequency, or laser, which provides predictable necrosis with a low complication rate. Preliminary data indicated that radiofrequency ablation is superior to ethanol injection in the radicality of tumor ablation. The advent of more versatile radiofrequency probes has allowed ablation of HCCs larger than 5 cm. Recent studies have suggested that combined transarterial embolization and heat ablation is a promising strategy for large HCCs. Thus far, no randomized trials comparing various thermoablative therapies have been reported. It is also uncertain whether a percutaneous route, laparoscopy, or open surgery affords the best approach for these therapies. Thermoablative therapies have been combined with resection or used to treat postresection recurrence, and they have also been used as a pretransplant therapy. However, the value of such strategies requires further evaluation. Advances in locoregional therapies have led to a major breakthrough in the management of unresectable HCC, but the exact role of the various modalities needs to be defined by randomized studies. Novel thermoablative techniques provide the surgeon with an exciting opportunity to participate actively in the management of unresectable HCC. Locoregional therapies are also useful adjuncts in the management of patients with resectable or transplantable disease. Hence, surgeons must be equipped with the latest knowledge and techniques of ablative therapy to provide the most appropriate treatment for the wide spectrum of patients with HCC.

Radiofrequency ablation of liver metastases. Technique and initial results

Primary and secondary malignant hepatic tumors are the most common tumors with a much more higher incidence of hepatic metastases. Chemotherapy and radiation therapy are in general ineffective. Therefore, surgical resection is considered the method of choice in the treatment of malignant hepatic lesions. Due to systemic disease, general medical or procedure-related reasons hindering surgery, only 25 to 45% of the patients with metastatic disease of the liver are suitable for a curative surgical therapy. In resectable lesions thermoablative methods can offer an alternative to the surgical therapy. The most experience exists in radiofrequency ablation techniques. Technique, indications, contraindications, and limitations of the radiofrequency ablation will be discussed together with a presentation of own cases and a review of the literature. In 37 patients the primary technical success rate of the ablation was 97.3% (72 of 74 lesions). In 4 cases a hematoma of the liver capsule occurred. One of these had to be treated interventionally. During the limited follow-up period of 9 months no local recurrency was seen, however 4 patients developed new hepatic metastases. Beside differences in practicability it is not yet clarified if there are differences in the therapeutic efficacy of the different thermoablation methods. Nevertheless, the results of the ablation therapy may parallel the results of the surgical resection. Interstitial thermotherapy can provide a valuable contribution to local tumor control. However, the final significance of the thermoablation techniques within oncological therapy regimens has to be evaluated in further multidisciplinary studies.

MRI guidance of infra-red laser liver tumour ablations, utilising an open MRI configuration system: technique and early progress

Background/Aims: Primary and secondary liver tumours are a common clinical problem, with a poor prognosis in most cases. Surgical resection offers the best outcome, but is only appropriate for the minority. Thermal ablation techniques have been described, but the lack of an optimal means of monitoring has limited their use. We undertook a pilot study to assess the feasibility and safety of an integrated MR-guided laser thermoablation technique under local anaesthesia using a real-time colourisation thermal monitoring technique in a newly developed open MR scanner. Methods: Liver tumours were punctured after the administration of intravenous Mangafodipir trisodium (MnDPDP) using real-time MR image guidance under local or general anaesthesia, and treated using a water-cooled interstitial fibre and a Nd-YAG laser source. Twenty-seven procedures were performed in 12 patients. Therapy was monitored using a real-time MR colourisation sequence. Thermoablation was followed by a colour change in a region of interest. Results: Thermal lesions of mean size 3 cm in diameter were produced with a maximum size of 5 cm. Eight out of 12 patients were discharged the next day with few significant complications. Repeat procedures have been performed in seven of 12 patients. Two patients with lesions of 3 cm diameter have had complete tumour ablation with only one procedure. Conclusion: Percutaneous laser thermoablation for liver tumours performed as an integrated one-step technique in an open configuration MR scanner is described. It can be safely performed under local anaesthesia in the majority of patients, with few side effects. MR control shows the site and size of the evolving thermal lesions, allowing appropriate action to be taken in terms of further burns, time of application and power applied.

The efficacy and safety of argon plasma coagulation therapy in Barrett's esophagus

Background: Thermoablation is being used to eliminate the metaplastic epithelium of Barrett's esophagus and allow its reversal into squamous epithelium in an acid-controlled environment. This study assessed the efficacy and safety of a new thermoablation technique, argon plasma coagulation. Methods: Patients with circumferential Barrett's esophagus 2 to 5 cm long were enrolled. Acid suppression was accomplished with lansoprazole. One-half the circumference of Barrett's mucosa was treated with argon plasma coagulation, and the other half served as an internal control. After macroscopic squamous re-epithelialization occurred, biopsy specimens were obtained from both areas systematically. Results: Nine patients, all men with a mean age of 51.1 years, completed the study. During 24-hour esophageal pH monitoring a pH less than 4 occurred on average 2.8% of the time with a mean dose of lansoprazole of 70 mg/day. Squamous re-epithelialization developed in treated areas in all 9 patients. Biopsy showed that 7 of 9 patients (77.8%) had squamous re-epithelialization without intestinal metaplasia. Biopsy showed that 2 of 9 patients (22.2%) had squamous re-epithelialization with evidence of underlying intestinal metaplasia. There were no serious complications. Conclusions: Argon plasma coagulation in an acid-controlled environment was both efficacious and safe in the treatment of Barrett's esophagus. However, the reappearance of squamous epithelium after therapy did not exclude the presence of underlying intestinal metaplasia. (Gastrointest Endosc 1999;50:18-22.)

Reconstitution of Squamous Epithelium in Barrett's Oesophagus with Endoscopic Argon Plasma Coagulation: A Prospective Study

Background: Barrett's oesophagus is a premalignant condition. Recent reports have suggested that laser coagulation or photodynamic therapy combined with acid suppression may induce reconstitution of squamous mucosa. However, a high percentage of residual glands remain in cases treated with both techniques. Argon plasma coagulation (APC) appears to be an attractive alternative to other thermoablative techniques. The aim of this study was to investigate the reconstitution of squamous epithelium in Barrett's oesophagus after APC. Methods: Fifteen patients with histologically proven Barrett's oesophagus were included in a prospective study. After base-line documentation by videotaping and biopsies, Barrett's epithelium was treated by repeated APC at intervals of 4-6 weeks until complete squamous restoration was achieved. All patients were kept under high-dose proton pump inhibitor therapy. Results: In 13 patients complete reconstitution of squamous epithelium was achieved. Buried glands after squamous restoration were detected transiently in only one case after the first session. As side effects seven patients had mild retrosternal discomfort. One patient reported severe retrosternal pain for 1 week. He then refused further APC sessions. Another patient was excluded because of noncompliance. During the follow-up period (6-13 months) recurrence of Barrett's epithelium was observed in one patient. Conclusions: APC is a suitable technique for achieving squamous restoration in Barrett's oesophagus. The rare occurrence of remaining buried glands may result from the homogeneous coagulation achieved by the ionized argon gas beam.