Factors contributing to cavitation after CT-guided percutaneous radiofrequency ablation for lung tumors

Cavitation has been described in lung neoplasms after radiofrequency ablation (RFA). In this retrospective study, the frequency and timing of cavitation after RFA of unresectable lung tumors was analyzed to determine the factors that contribute to cavitation and to assess the clinical course of patients who develop cavitation.

The authors retrospectively studied 100 lung RFA lesions in 48 patients (37 men, 11 women, age 69.7 years +/- 10.7, mean +/- SD) who underwent lung RFA between June 2000 and March 2006. RFA was performed using a LeVeen electrode inserted under guidance by computed tomography (CT). Follow-up consisted of CT performed at 1 week, 1 month, and every 2 to 3 months thereafter to determine the frequency of, time of radiographic appearance of, and factors contributing to cavity formation and the clinical course after cavitation.

Cavitation was detected by CT at 1.5 months +/- 0.8 after RFA (14 sessions). No symptoms were noted in 12 sessions, but high fever developed after 1 month in two sessions. The frequency of cavitation was significantly higher in patients with lung cancer as the primary lesion (10/14), those who underwent RFA for lesions located within 1 cm of the chest wall (11/14), and those with pulmonary emphysema (7/14) (P < .05). Age, sex, maximum power output,total ablation time, minimum impedance, and tumor diameter were not significant contributors to cavity formation.

In our study, cavitation occurred at a frequency of 14% at 1.5 months +/- 0.8 after RFA ablation, but the majority of patients were asymptomatic. Cavitation seems to occur more frequently in patients with a lesion near the chest wall, lung cancer as the primary lesion, and in those with pulmonary emphysema at baseline before the lung RFA.