Background In patients with hepatocellular carcinoma (HCC) who undergo follow-up with CT after treatment, the benefit of routinely including pelvic coverage is not well substantiated. Purpose To investigate the added value of pelvic coverage at follow-up liver CT in detecting pelvic metastasis or incidental tumors in patients treated for HCC. Materials and Methods This retrospective study included patients who were diagnosed with HCC between January 2016 and December 2017 and followed up with liver CT after treatment. Cumulative rates of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were estimated by using the Kaplan-Meier method. Cox proportional hazard models were used to identify risk factors for extrahepatic and isolated pelvic metastases. Radiation dose from pelvic coverage was also calculated. Results A total of 1122 patients (mean age, 60 years ± 10 [SD]; 896 men) were included. The cumulative rates at 3 years of extrahepatic metastasis, isolated pelvic metastasis, and incidental pelvic tumor were 14.4%, 1.4%, and 0.5%, respectively. At adjusted analysis, protein induced by vitamin K absence or antagonist-II (<i>P</i> = .001), size of the largest tumor (<i>P</i> = .02), T stage (<i>P</i> = .008), and initial treatment method (<i>P</i> < .001) were associated with extrahepatic metastasis. Only T stage was associated with isolated pelvic metastasis (<i>P</i> = .01). Because of pelvic coverage, the radiation dose increased by 29% and 39% in liver CT with and without contrast enhancement, respectively, compared with CT scans without pelvic coverage. Conclusion The incidence of isolated pelvic metastasis or incidental pelvic tumor was low in patients treated for hepatocellular carcinoma. © RSNA, 2023.

MWA appears to be a safe and effective treatment for early-stage HCC, demonstrating durable tumor control and a low incidence of major complications over 3 years.