Microwave ablation of lung malignancies: effectiveness, CT findings, and safety in 50 patients.
OBJECTIVE
To retrospectively evaluate effectiveness, follow-up imaging features, and safety of microwave ablation in 50 patients with intraparenchymal pulmonary malignancies.


METHODS
This HIPAA-compliant study was approved by the institutional review board; informed consent was waived. From November 10, 2003, to August 28, 2006, 82 masses (mean, 1.42 per patient) in 50 patients (28 men, 22 women; mean age, 70 years) were percutaneously treated in 66 microwave ablation sessions. Each tumor was ablated with computed tomographic (CT) guidance. Follow-up contrast material-enhanced CT and positron emission tomographic (PET) scans were reviewed. Mixed linear modeling and logistic regression were performed. Time-event data were analyzed (Kaplan-Meier survival estimates and log-rank statistic). All event times were the time to a patient's first event (alpha level = .05, all analyses).


RESULTS
At follow-up (mean, 10 months), 26% (13 of 50) of patients had residual disease at the ablation site, predicted by using index size of larger than 3 cm (P = .01). Another 22% (11 of 50) of patients had recurrent disease resulting in a 1-year local control rate of 67%, with mean time to first recurrence of 16.2 months. Kaplan-Meier analysis yielded an actuarial survival of 65% at 1 year, 55% at 2 years, and 45% at 3 years from ablation. Cancer-specific mortality yielded a 1-year survival of 83%, a 2-year survival of 73%, and a 3-year survival of 61%; these values were not significantly affected by index size of larger than 3 cm or 3 cm or smaller or presence of residual disease. Cavitation (43% [35 of 82] of treated tumors) was associated with reduced cancer-specific mortality (P = .02). Immediate complications included pneumothorax (Common Terminology Criteria for Adverse Events [CTCAE] grades 1 [18 of 66 patients] and 2 [eight of 66 patients]), hemoptysis (four of 66 patients), and skin burns (CTCAE grades 2 [one of 66 patients] and 3 [one of 66 patients]).


CONCLUSIONS
Microwave ablation is effective and may be safely applied to lung tumors. (c) RSNA, 2008.
Wolf
Farrah J
FJ
Departments of Diagnostic Imaging and Radiation Oncology, Office of Research Administration, Rhode Island Hospital, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02903. the 2007 RSNA Annual Meeting.
Grand
David J
DJ
Machan
Jason T
JT
Dipetrillo
Thomas A
TA
Mayo-Smith
William W
WW
Dupuy
Damian E
DE
D000368:Aged; D017115:Catheter Ablation / Q000295:instrumentation*; D003287:Contrast Media; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D012189:Retrospective Studies; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
D003287:Contrast Media