CIO 2022-25 Risk Factors for Abscess Development Following Percutaneous Microwave Ablation Therapy of Hepatic Tumors

*Late-Breaking Abstract

Purpose: To investigate risk factors associated with post-microwave ablation (MWA) abscess development.

Methods: A retrospective case-control analysis was conducted to identify hepatic MWA performed at a single tertiary medical center between January 2010 and January 2022. Case and control patients were defined as those who did or did not develop intrahepatic abscess within 4 months following MWA, respectively. Correlations between risk factors and post-MWA abscess development were assessed by Fisher’s exact test and logistic regression analysis.

Results: Between 2010-2022, 256 patients underwent 349 MWA sessions with post-ablation abscess complication rate of 1.15% (4/349). Complications associated with intrahepatic abscess included bacteremia, empyema, pleural abscess, subcutaneous abscess, cholangitis, bile leak, biliocutaneous and arterio-biliary fistulae, and pseudoaneurysm. One patient expired from septic shock 5 days post-ablation. All abscesses were treated by percutaneous drainage and antibiotics. One patient required concomitant placement of a biliary stent and embolization of a biliocutaneous tract. History of Sphincter of Oddi manipulation and cholangiocarcinoma were significantly correlated with post-MWA abscess (odds ratio = 48.6 and 42.0, p < 0.01, respectively). The risk of developing post-MWA abscesses for patients with a history of cholangiocarcinoma or a history of Sphincter of Oddi manipulation were 20.0% and 27.2%, respectively. There was no significant association between MWA and abscess development in patients with prior liver-directed therapy or who received standard preprocedural antibiotic prophylaxis (p = 1.0 and 0.13, respectively). Standard pre-procedural antibiotic treatment was not significantly correlated with abscess development in MWA-treated patients, and more aggressive antibiotics regimens may be warranted in patients with risk factors for post-MWA abscess formation.

Conclusions: Patients with prior Sphincter of Oddi manipulation or cholangiocarcinoma are at greater risk of developing post-MWA abscess.