Development and Identification of a Nomogram Prognostic Model for Patients with Primary Clear Cell Carcinoma of the Liver

BACKGROUND Primary clear cell carcinoma of the liver (PCCCL) is an infrequent variant of primary hepatocellular carcinoma (HCC), we retrospectively performed a large population-based cohort study to elucidate the relationships between demographic, carcinoma- and therapy-specific variables and overall survival (OS). MATERIAL AND METHODS The Surveillance, Epidemiology and End Results (SEER) database was queried to extract data on 419 patients with pathologically confirmed PCCCL from 1988 to 2015. A nomogram with good accuracy was formulated to predict long-term survival of PCCCL patients. RESULTS The OS for PCCCL patients was 25.6 months (95% confidence interval [CI]: 22.2-29 months), the overall 1-year, 3-year, and 5-year survival rates were 59.5%, 39.3%, and 29.9%, respectively. Log-rank analysis revealed that there was no statistically significant discrepancy in clinical outcome between PCCCL and common-type HCC after propensity-matched analysis. Multivariate Cox analysis confirmed that larger lesions (>96 mm), distant metastases and elevated alpha-fetoprotein (AFP) levels were independent prognostic factors for undesirable outcome. Conversely, surgery was an independent protective factor (hazard ratio [HR]=0.23, 95% CI 0.17-0.31), which significantly boosted OS by virtually 35 months (47.3 months versus 12.7 months, P<0.001). Radiotherapy or chemotherapy was not associated with OS for PCCCL patients (both P>0.05). The nomogram incorporated 4 independent prognostic factors and its concordance index for predicting survival was 0.761. CONCLUSIONS The prognosis of PCCCL resembled that of common-type HCC. Larger lesions, distant metastases, and enhanced AFP levels were associated with unsatisfactory prognosis. Surgery fulfill favorable prognosis while radiotherapy or chemotherapy exerted no significant effects on survival.