Preliminary single-operator experience with ultrasound-guided liver core needle biopsy performed by a supervised general surgery resident.

Objective: Ultrasound-guided core needle biopsy (CNB) is essential for diagnosing liver tumors not amenable to resection, but the outcomes of resident-performed CNB are poorly defined. We evaluated the diagnostic performance and safety of liver CNB performed by a single ultrasound-certified general surgery resident under specialist supervision. Material and Methods: In this retrospective single-center case series, 65 consecutive patients underwent ultrasound-guided liver CNB between July 2022 and January 2025. All procedures constituted the resident's entire initial experience with liver CNB. Diagnostic success was defined as obtaining sufficient tissue for definitive histopathological diagnosis. Predictors of diagnostic success were assessed using univariate analyses and logistic regression. Learning-curve effects were evaluated by comparing early and late tertiles of chronologically ordered cases and by modelling case number as a continuous predictor. The impact of lesion size was examined by subgroup analysis comparing <4 cm and ≥4 cm lesions and by treating the maximal lesion diameter as a continuous variable. Results: Adequate tissue was obtained in 58/65 biopsies (89.2%), with malignancy confirmed in 49 patients (75.4%) and benign lesions in 9 patients (13.8%). Diagnostic success was 85.7% in the early tertile and 95.5% in the late tertile (p=0.345). Logistic regression showed a non-significant trend toward a higher diagnostic yield over time. Neither lesion size (categorized as <4 cm versus ≥4 cm) nor maximal diameter (analyzed as a continuous variable) was significantly associated with diagnostic success. No immediate or clinically overt delayed complications were observed during 24 hours of in-hospital monitoring. Conclusion: This preliminary single-operator experience suggests that, under close supervision, an appropriately trained general surgery resident can perform ultrasound-guided liver CNB with a high diagnostic yield and a low observed complication rate. These hypothesis-generating findings support further multi-operator and comparative studies of resident-performed liver CNB.