Sequential liquid-based cytology based on exfoliative cells of 18-gauge core needle groove to improve renal mass core needle biopsy yield: a real-world observational study

BACKGROUND: Renal mass biopsy (RMB) has regained clinical interest in recent years due to the pursuit of individualized and precision medicine. Renal mass core needle biopsy (RMCNB) for histopathology (HP), with or without liquid-based cytology (LBC), has been used increasingly in our hospital. This study investigated factors influencing the HP diagnostic yield of RMCNB, and compared the diagnostic rate between HP alone and HP plus LBC. METHODS: In this retrospective cross-sectional study, a total of 134 patients who underwent ultrasound-guided percutaneous RMCNB in the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between January 2015 and May 2022 were enrolled. All biopsies were performed using an 18-gauge core needle biopsy gun, and the sampling tissues and exfoliative cells of 18-gauge core needle groove were delivered for HP and LBC diagnosis, respectively. The patient demographics, clinical indications, tumor characteristics, number of biopsies, final pathological diagnosis, and follow-up data were reviewed. Univariate and multivariate logistic regression analyses were performed to evaluate the association between variables and HP diagnostic yield of RMCNB. The diagnostic rate between HP and HP plus LBC was compared using McNemar’s test and agreement was evaluated using the Kappa score. RESULTS: The most common indication of RMCNB was renal masses with a radiological diagnosis of locally advanced disease or distant metastasis (86.6%). The HP diagnostic yield was established in 88.1% (118/134) of cases, and the diagnostic rate of HP plus LBC was 94.0% (126/134). Logistic regression analyses revealed that non-enhanced area exceeding 50% [odds ratio (OR): 0.021, 95% confidence interval (CI): 0.003–0.134, P<0.001] and number of core biopsies (OR: 9.479, 95% CI: 1.528–58.794, P=0.016) were associated with the HP diagnostic yield of RMCNB. The diagnostic rate of HP plus LBC was significantly higher than that of HP alone (94.0% vs. 88.1%, P=0.008), and they showed substantial agreement (Kappa =0.638, P<0.001). Meanwhile, in the non-enhanced area ≥50% subgroup, the diagnostic rate between HP plus LBC and HP alone was significantly different (86.7% vs. 60%, P=0.008), and the agreement was fair (Kappa =0.375, P=0.009). CONCLUSIONS: RMCNB has a high diagnostic yield with a minimum of two high-quality core biopsies, LBC can improve the diagnostic yield of HP alone, especially in masses with large non-enhanced area.