Subcapsular liver tumors treated with percutaneous radiofrequency ablation: a prospective comparison with nonsubcapsular liver tumors for safety and effectiveness.
OBJECTIVE
To assess the safety and effectiveness of percutaneous radiofrequency (RF) ablation of subcapsular liver tumors.


METHODS
The study protocol was approved by the institutional review board, and all patients gave written informed consent. One hundred eighty-one patients (79 men, 102 women; age range, 36-85 years) underwent ultrasonographically (US) guided percutaneous RF ablation of 361 primary or secondary (metastatic) liver tumors. Forty-four patients had one or more subcapsular nodules (group 1), and 137 had nonsubcapsular nodules only (group 2). Overall, 80 nodules were subcapsular and 281 were nonsubcapsular. The completeness of the ablation was assessed with contrast material-enhanced computed tomography (CT) 1 month after RF ablation. If residual tumor was documented, RF ablation was repeated. All patients in whom the ablation was complete after the first or second ablation session were monitored with CT or contrast-enhanced US every 3 months. Major complication, complete ablation, and local tumor progression rates were compared by using the chi(2) test or Fisher exact test.


RESULTS
Three (7%) major complications (intraperitoneal bleeding, skin burn, and tumor seeding) occurred in group 1, and two (1.5%) cases of tumor seeding occurred in group 2 (P = .093). No RF ablation-related deaths occurred. The complete ablation rate was 98% (43 of 44 patients) in group 1 and 98.5% (135 of 137 patients) in group 2 (P = .756). The local tumor progression rate after a median follow-up of 25 months (range, 13-54 months) was 16% (seven of 43 patients) in group 1 and 9.6% (13 of 135 patients) in group 2 (P = .355).


CONCLUSIONS
The difference in major complication rate between the subcapsular and nonsubcapsular liver tumors was not significant. The safety of RF ablation of subcapsular tumors seems acceptable, and the effectiveness is comparable to that of RF ablation of nonsubcapsular tumors.
Department of Internal Medicine, Section of Interventional Ultrasound, St Anna Hospital, Corso Giovecca 203, 44100 Ferrara, Italy. srs@unife.it
Sergio
S
Sartori
Paola
P
Tombesi
Francesca
F
Macario
Ingrid
I
Nielsen
Davide
D
Tassinari
Mirella
M
Catellani
Vincenzo
V
Abbasciano
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D017115:Catheter Ablation; D016009:Chi-Square Distribution; D003287:Contrast Media; D018450:Disease Progression; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D014463:Ultrasonography
D003287:Contrast Media