Influence of clinical and tumor characteristics on survival in patients with hepatocellular carcinoma with bone metastasis.

525 Background: Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, and the incidence of liver cancer is rapidly rising in the United States. Advanced HCC generally has a dismal prognosis with an expected survival of less than 1 year. Bone metastases from HCC are infrequent with a poorer prognosis. However, the factors influencing their survival are not well-understood. We aimed to study the effects of clinical and tumor characteristics on survival in HCC patients with bone metastasis. Methods: We selected adult patients with HCC who had bone metastasis diagnosed between 2004 and 2019 using the National Cancer Database (NCDB). We described baseline characteristics using percentages. We performed the Kaplan-Meier method to calculate the median overall survival (OS). We included demographics (age at diagnosis, gender, race, insurance status), comorbidity score, and treatment characteristics. Results: Of a total of 3301 HCC patients with bone metastasis, 87.1% were male, and 12.9% were female. Among all, 72.2% were white, 19.3% were black, and 8.5% were others. A total of 59.9% of patients were <65 years. Eighty-six-point four percent of the patients had a total Charlton-Deyo comorbidity score of <3 and 13.6% had it ≥3. Among patients with known tumor grade, 25.4% had well differentiated, 37.8% moderately differentiated, 35.4% poorly differentiated, and 1.2% undifferentiated tumors. In univariate analysis, patients with well-differentiated tumors had better OS compared to poorly differentiated tumors (5.4 mo vs. 3.3 mo, p<0.05). In treatment groups, both single and multi-agent chemotherapy as first-course therapy significantly improved OS compared to patients’ chemotherapy was not administered (6.8 mo vs. 2.1 mo; 8.9 mo vs. 2.1 mo, respectively). We found no mortality difference between age, gender and race groups. Conclusions: In this cohort analysis of NCDB data, we report better OS in treatment receipt, lower tumor grade, and lower comorbidity score in HCC patients with bone metastasis. Previous studies of HCC patients with bone metastasis have been limited by small sample sizes, and lack of nationwide oncology outcomes data. Further large-scale prospective studies are needed.