Predictors and survival of primary clear cell carcinoma of liver: a population-based study of an uncommon primary liver tumor

BACKGROUND: The clinicopathological features and prognostic factors of primary clear cell carcinoma of the liver (PCCCL) remain unknown for the rarity. We aimed to determine the clinical and therapeutic characteristics of PCCCL and the effects of these factors on the prognosis. METHODS: Patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Data were analyzed with the Kaplan-Meier, Cox proportional hazards regression analyses and the multivariable competing risk model. RESULTS: We included 223 PCCCL patients and the majority of them had an age under 75 years (82.5%). Most patients were white people (63.2%). The patients diagnosed at localized stage (63.7%), T1 (49.8%), N0 (96.0%), M0 (87.4%) and American Joint Committee on Cancer (AJCC) I (44.4%) made up the majority of the population. More PCCCL tumors had a size beneath 4 cm (74.9%) and no vascular invasion (63.2%). The 3-, 5-, and 10-year overall survival (OS) probabilities and disease-specific survival (DSS) rates were 35.8%, 24.3%, 14.4%, and 41.6%, 29.4%, 22.2%, respectively. The patients with tumor ≥1 cm [OS, hazard ratio (HR) =1.822; DSS, HR =1.959] had a higher risk of death than those patients with tumor <1 cm. Among surgical means, hepatectomy (OS, HR =0.070; DSS, HR =0.050) and total hepatectomy plus transplant (OS, HR =0.074; DSS, HR =0.065) were more beneficial to PCCCL. CONCLUSIONS: PCCCL patients were inclined to be young, white people-prevalent, localized and early. PCCCL tend to had a slow growth and be weakly aggressive. However, comparing with previous reports, we found that PCCCL had a relatively poor outcome. Tumor size and surgery were the independent prognostic factors for OS and DSS.