Identification of the risk factors for liver abscess after CT-guided interstitial brachytherapy and the evaluation of intensified antibiotic prophylaxis.

PURPOSE: To identify the risk factors for liver abscess in patients undergoing CT-guided interstitial brachytherapy, and the effectiveness of intensified antibiotic prophylaxis regimen in patients with assumed high-risk. METHODS: All patients who underwent CT-guided high-dose-rate interstitial brachytherapy of liver lesions between July 2017 and June 2022 at a single center were retrospectively evaluated. Patients with a follow-up shorter than 1 month were excluded. No routine periinterventional antibiotic prophylaxis was used. Patients with assumed risk factors (enterobiliary manipulations, biliary dilatation, central large tumor) were prescribed with 10-day ciprofloxacin and metronidazol, followed by ciprofloxacin for a week every month. Risk factors were identified using multivariable logistic regression and LASSO. RESULTS: 560 patients with 862 interstitial brachytherapy sessions were included. Of 55 patients with risk factors, 42 received antibiotic prophylaxis and 13 did not. The rate of liver abscess was 1.04% (9 of 862 procedures) per procedure and 1.6% (9 of 560 patients) per patient. The rate of hepatic abscess was 0.39% in patients without risk factors. Multivariable analysis and LASSO showed a significant correlation between liver abscess and the presence of biliodigestive anastomosis (p < 0.001) and biliary stent (p < 0.001). The rate of liver abscess in patients with enterobiliary manipulations was 23% (3 of 13) without antibiotic prophylaxis and 11.7% (4 of 34) under antibiotic prophylaxis (p = 0.376). CONCLUSION: The risk of liver abscess after CT-guided interstitial brachytherapy is extremely low in patients without risk factors. Biliodigestive anastomosis is a risk factor for liver abscess, and intensified antibiotic prophylaxis shows a trend to decrease liver abscess risk.