Preoperative Assessment of Hepatocellular Carcinoma Tumor Grade Using Needle Biopsy

TLDR

The accuracy of preoperative needle core biopsy (NCB) for predicting final hepatocellular carcinoma (HCC) tumor grade has not been previously evaluated, yet tumor grade is used to select transplant candidates. This study aimed to assess the diagnostic agreement between preoperative NCB tumor grading and final surgical pathology in HCC patients. The authors retrospectively analyzed 211 HCC patients (120 with NCB) from 1998–2004, collecting clinicopathologic and biopsy data and applying chi‑square and kappa statistics. The study found poor agreement between NCB and surgical pathology (kappa = 0.18), with NCB grade failing to predict microscopic vascular invasion while final grade did, indicating that NCB tumor grading may mislead transplant selection.

Abstract

To examine the diagnostic agreement of preoperative needle core biopsy (NCB) grading of hepatocellular carcinoma (HCC) compared with the final surgical pathologic tumor grade.Some centers have adopted protocols for selecting patients with HCC for transplantation based on tumor grade as determined by preoperative NCB. The validity of NCB to predict final tumor grade has not been previously assessed.A total of 211 patients who underwent hepatic resection, open radiofrequency, or transplantation for HCC between 1998 and 2004 were identified. Clinicopathologic, NCB, and surgical data were collected and analyzed using chi and kappa statistics.A total of 120 (67.4%) of the 178 who underwent resection or transplantation had an NCB. On preoperative NCB, the majority of HCC cases were classified as well-differentiated (n = 35; 37.6%) or moderately differentiated (n = 44; 47.3%), while 14 (15.1%) cases were categorized as poorly differentiated. In contrast, when tumor grading was based on the final surgical specimen, there was a significantly higher proportion of HCC cases graded as poorly differentiated (well-differentiated, n = 34; 36.6%; moderately differentiated, n = 33; 35.5%; poorly differentiated, n = 26; 27.9%) (P < 0.05). The overall percent agreement of NCB and surgical pathology to determine tumor grade was poor (kappa = 0.18, P < 0.0001). Whereas final pathologic tumor grade predicted the presence of microscopic vascular invasion (well, 15.7%; moderate; 31.9%, poor; 58.4%; P = 0.001), NCB grade did not (well, 23.7%; moderate, 28.0%; poor, 25.4%; P = 0.65).Selection of candidates for transplantation based on NCB tumor grade may be misleading, as NCB tumor grade often did not correlate with grade or presence of microscopic vascular invasion on final pathology. Clinicomorphologic criteria (tumor size, number) should remain the major determinants of eligibility for transplantation.