Reclassification of tumor size for solitary HBV-related hepatocellular carcinoma by minimum p value method: a large retrospective study

Abstract

Abstract Background and objectives Tumor size is one of the most important issues for hepatocellular carcinoma (HCC) treatment and prognosis, but the classification of it is still controversial. The aim of this study was to screen appropriate cutoffs for size of solitary hepatitis B virus (HBV)-related HCC. Methods A cohort of 1760 patients with solitary HBV-related HCC undergoing curative liver resection was divided into 11 groups based on tumor size in 1-cm interval. The minimum p value method was used to screen the appropriate size cutoff according to overall survival (OS). If multiple cutoffs meet the above standard, a univariate analysis will be performed by using the Cox proportional hazards regression model, and hazard ratio (HR) will be considered as a criterion to assess the difference in survival. Results There are 8 dichotomy, 8 trichotomy, and no inquartation cutoffs that were screened when classifying tumor sizes in accordance with OS. The HR values of tumor size at these trichotomy cutoffs for OS were compared, and the highest HR value is 2.79 when size cutoff is 3/9 cm. Then, we reclassified patients into three new classifications: ≤ 3 cm (n = 422), > 3 and ≤ 9 cm (n = 1072), and > 9 cm (n = 266). The comparison of clinicopathologic characteristics among these three classifications showed that the increase of tumor size was associated with the increase of α-fetoprotein (AFP), microvascular invasion (MVI), tumor differentiation, and liver cirrhosis. And the comparison of the OS among three classifications showed statistical differences. Conclusions This study suggested that size criteria of 3 cm and 9 cm in solitary HBV-related HCC patients were appropriate based on biological characteristics and prognostic significance.