Tumor complete response and pyogenic liver abscess secondary to concurrent microwave ablation plus atezolizumab and bevacizumab in liver cancer: a case report.

Background: Pyogenic liver abscess (PLA) could be fatal even after standard treatment with antibiotics and percutaneous drainage. Immune checkpoint inhibitors, bevacizumab or microwave ablation may cause PLA, respectively. This paper presents the first case of PLA secondary to the concomitant use of microwave ablation with atezolizumab and bevacizumab in the treatment of liver cancer.

Case description: A 54-year-old Chinese man with Barcelona Clinic Liver Cancer (BCLC) C-stage liver cancer complained of fever and chills twenty-nine days after concurrent microwave ablation plus atezolizumab and bevacizumab. Post-hospitalization, a computed tomography revealed a rim-enhancing hypodensity within the right lobe of the liver, approximately 8.8 cm in diameter containing foci of gas. Laboratory examination revealed elevated white blood cell count, C-reactive protein and procalcitonin, and blood culture indicated the presence of Escherichia coli bacteremia. The patient was diagnosed with PLA complicated by septic shock, and due to recurrent fever, multiple courses of antibiotics (imipenem/cilastatin sodium, cefoperazone/sulbactam, meropenem, respectively) were administered in combination with five percutaneous drainages over the next 90 days. The patient's fever eventually resolved, and the patient was discharged. The patient was re-treated with two cycles of atezolizumab and bevacizumab initiated in March 2024. An imaging evaluation in May 2023 demonstrated tumor progression. Subsequently, the patient underwent one transarterial chemoembolization procedure and two cycles of atezolizumab and bevacizumab over the subsequent 2 months. Notably, the patient achieved a complete response at the July 2024 imaging evaluation.

Conclusions: In patients undergoing atezolizumab and bevacizumab, the potential risk of PLA versus the antitumor benefit of microwave ablation requires to be assessed. The use of multiple courses of antibiotics over a prolonged period did not appear to influence the effectiveness of atezolizumab and bevacizumab. Further studies are, however, needed to substantiate this finding.