**4.10. RFA of thyroid metastasis**

Guidelines on thyroid cancer from the National Comprehensive Cancer Network (NCCN, 2010) state that distant metastases from recurrent or persistent medullary thyroid carcinoma that are causing symptoms (e.g., those in bone) could be considered for palliative resection, RFA, or other regional treatment. The guidelines state that these interventions may also be considered for asymptomatic distant metastases (especially for progressive disease) but observation is acceptable, given the lack of data regarding alteration in outcome (44). Monchik and colleagues evaluated the long-term effectiveness of RFA and percutaneous ethanol (EtOH) injection treatment of patients with local recurrence or focal distant metastases of well-differentiated thyroid cancer (WTC). A total of 20 patients underwent treatment of biopsy-proven recurrent WTC in the neck. Sixteen of these patients had lesions treated by ultrasound-guided RFA (mean size, 17.0 mm; range of 8 to 40 mm), while 6 had ultrasound-guided EtOH injection treatment (mean size, 11.4 mm; range of 6 to 15 mm). Four patients underwent RFA treatment of focal distant metastases from WTC. Three of these patients had CT-guided RFA of bone metastases (mean size, 40.0 mm; range of 30 to 60 mm), and 1 patient underwent RFA for a solitary lung metastasis (size, 27 mm). Patients were then followed with routine ultrasound, whole body scan, and/or serum thyroglobulin levels for recurrence at the treatment site. No recurrent disease was detected at the treatment site in 14 of the 16 patients treated with RFA and in all 6 patients treated with EtOH injection at a mean follow-up of 40.7 and 18.7 months, respectively. Two of the 3 patients treated for bone metastases were disease-free at the treatment site at 44 and 53 months of follow-up, respectively. The patient who underwent RFA for a solitary lung metastasis was disease-free at the treatment site at 10 months of follow-up. No complications were experienced in the group treated by EtOH injection, while 1 minor skin burn and 1 permanent vocal cord paralysis occurred in the RFA treatment group. The authors concluded that RFA and EtOH ablation show promise as alternatives to surgical treatment of recurrent WTC in patients with difficult reoperations. They stated that further long-term follow-up studies are needed to ascertain the precise role these therapies should play in the treatment of recurrent WTC (45).

#### **4.11. RFA of Soft tissue masses**

158 Hyperthermia

of Gastroenterology's updated guidelines for the diagnosis, surveillance and therapy of BE , Wang and Sampliner states that "further evaluation of the most recent technology; radiofrequency ablation is awaited. Cryotherapy is beginning clinical trials and older technologies are becoming more refined (e.g., photodynamic therapy with the development of new agents). Documentation of the frequency and duration of the surveillance protocol

Yeh and Triadafilopoulos noted that a wide variety of endoscopic mucosal ablative techniques have been developed for early esophageal neoplasia. However, long-term control of neoplasic risk has not been demonstrated. The authors explained that most studies show that specialized intestinal metaplasia may persist underneath neo-squamous mucosa, posing a risk for subsequent neoplastic progression (41). Shaheen noted that the pathogenesis of BE is poorly understood. Given that some patients will have repeated bouts of severe erosive esophagitis and never develop BE, host factors must play an important role. The author stated that the utility of neoadjuvant radiation and chemotherapy in those with adenocarcinoma, although they are widely practiced, is not of clear benefit, and some authorities recommend against it. Ablative therapies, as well as endoscopic mucosal resection, hold promise for those with superficial cancer or high-grade dysplasia. The author noted that most series using these modalities feature relatively short follow-up; longer-term

studies are needed to better ascertain the effectiveness of these treatments (38).

Pedrazzani et al evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of BE that is considered to be the main risk factor for the development of esophageal adenocarcinoma. They found that high power setting APC showed to be safe. The effects persist at a mean follow-up period of 2 years with a comparable cost in term of complications with respect to standard power settings. The authors stated, however, that further studies with greater number of patients are required to confirm these results and to assess if ablation reduces the incidence of malignant progression (42). Hage et al stated that although endoscopic removal of BE by ablative therapies is possible in the majority of patients, histologically complete elimination can not be achieved in all cases. Persistent BE may still harbor molecular aberrations and must therefore be considered still to be at risk of

Guidelines on thyroid cancer from the National Comprehensive Cancer Network (NCCN, 2010) state that distant metastases from recurrent or persistent medullary thyroid carcinoma that are causing symptoms (e.g., those in bone) could be considered for palliative resection, RFA, or other regional treatment. The guidelines state that these interventions may also be considered for asymptomatic distant metastases (especially for progressive disease) but observation is acceptable, given the lack of data regarding alteration in outcome (44). Monchik and colleagues evaluated the long-term effectiveness of RFA and percutaneous

after endoscopic ablation therapy requires careful study" (40).

**4.9. RFA of esophageal neoplasm** 

progression to adenocarcinoma (43).

**4.10. RFA of thyroid metastasis** 

Radiofrequency ablation devices have been cleared by the FDA for the general indication of soft tissue cutting, coagulation, and ablation by thermal coagulation necrosis. This clearance was based only on bench testing or animal testing performance data. Guidelines from the National Comprehensive Cancer Network (NCCN, 2010) include recommendations for RFA of the trunk and extremities in metastatic soft tissue sarcoma. The guidelines include metastasectomy with RFA as an alternative method for control of metastatic lesions in limited metastases. The guidelines also include RFA as options for symptomatic patients with disseminated metastases. "The guidelines are intentionally nonspecific about this group of options, because many different issues are factored into this decision (e.g., patient performance status, patient preferences, specific clinical problems from the metastases, treatment availability.)" (46).
