Particle therapy, a type of radiation therapy, can be categorized as proton beam and heavy particle therapy. Although the biological characteristics differ between the two types of radiation therapy, they share a common feature, i.e., high-dose concentration compared with conventional radiation (X-rays and gamma rays). The efficacy and safety of particle therapy have already been demonstrated in numerous solid tumors, and public insurance coverage has gradually been extended since 2016. Excellent local control and safety have also been reported for large hepatocellular carcinomas, which are difficult to be treated with stereotactic radiotherapy that uses X-rays, and insurance coverage for large tumors (with a diameter of ≥4 cm) was extended in April 2022. To date, particle therapy has been performed frequently on large tumors or in cases that are difficult to treat with other modalities. However, there is also growing evidence of noninferiority or superiority to existing treatments. As insurance coverage expands, particle therapy is expected to play an even greater role as part of the multidisciplinary treatment of hepatocellular carcinoma.

In Japan, oral direct-acting antiviral therapy for hepatitis C was introduced in 2014 and has been widely known for its high efficacy and safety. It contributes to an improved long-term prognosis in chronic liver disease. We conducted an intervention for hepatitis C virus (HCV) antibody-positive individuals who were not previously addressed to treat as many patients as possible. Of 1,180 eligible patients, 240 were contacted by medical institutions after excluding those with negative HCV RNA tests or HCV antibody titers < 4.0. Information letters were subsequently sent to 149 patients at their homes, and 9 patients made appointments to a hepatologist. Several studies on dealing with in-hospital patients have been conducted; however, only a few studies have focused on out-of-hospital patients. This intervention can help achieve microelimination and reduce the risk of litigation for patients from our hospital.

In a 40-year-old woman with no history of liver disease or alcohol consumption, contrast-enhanced abdominal computed tomography of a hepatic lesion demonstrated homogeneous dark staining in the arterial phase and washout in the portal venous phase, causing suspicion about hepatocellular carcinoma (HCC). The contrast-enhanced abdominal magnetic resonance imaging revealed that the lesion was slightly enhanced compared to the liver parenchyma in the early phase, washed out in the late phase, hypointense compared to the liver parenchyma in the 15-minute hepatocyte phase, and hyperintense in the diffusion-weighted imaging phase, lending support for the diagnosis of HCC. However, contrast-enhanced ultrasonography did not show any defects in the postvascular phase, which were not typical HCC findings. Given the challenging diagnosis, ultrasound-guided tumor biopsy was performed, leading to the diagnosis of hepatic angiomyolipoma.

A 70-year-old man with cirrhosis-sustained viral response following treatment for HCV (Child-Pugh class A) had two distinct treatment histories for single hepatocellular carcinoma (HCC) by radiofrequency ablation. A combination of atezolizumab and bevacizumab was initiated for treatment of HCC with lymph node metastasis. After seven treatment courses, he complained of nausea, malaise, and anorexia; laboratory data revealed eosinophilia. Furthermore, hormonal examination revealed hypopituitarism or hypothalamic adrenocortical insufficiency. Following hydrocortisone administration, the symptoms vanished and eosinophil counts normalized. Under continuous hydrocortisone administration, atezolizumab and bevacizumab was administered for 34 courses without persistent adrenal insufficiency, which was followed by three courses of durvalumab and tremelimumab combination therapy; subsequently cabozantinib was administered. Although hypoadrenalism is a relatively rare immune-related adverse event with non-specific symptoms, eosinophil count may serve as a useful marker. Furthermore, immune checkpoint inhibitors can be continued following appropriate corticosteroid administration.