Abstract: Objective To investigate the effect and safety of CyberKnife stereotactic radiotherapy in the treatment for abdominal lymph node metastases of primary hepatocellular carcinoma (PHCC). Methods Thirty-seven patients with abdominal lymph node metastases of PHCC who underwent CyberKnife radiotherapy in our hospital from January 2015 to September 2017 were enrolled. The total dose of CyberKnife radiotherapy ranged from 40Gy to 63Gy. The single dose ranged from 5Gy to 10Gy, divided into 4-10 fractions. Short-term therapeutic effect was assessed by Modified Response Evaluation Criteria in Solid Tumors. Long-term therapeutic effect was assessed by 1, 2, and 3-year overall survival rates and local control rates. The Kaplan-Meier method was used to calculate cumulative survival rate and local control rate. The log-rank test was used for the comparison of overall survival time between groups. Results The patients were followed up for 2-58 months, with an average of 14 months. Among all 37 patients, 8 (21.62%) achieved complete remission, 24 (64.86%) achieved partial remission, 4 (10.81%) achieved a stable condition, and 1 (2.70%) experienced disease progression. The effective rate was 86.48%, and the disease control rate was 97.29%. The 1, 2 and 3-year overall survival rates were 61.8%, 39.4% and 22.1%, respectively; The 1, 2 and 3- year local control rates were 86.0%, 80.3% and 63.1%, respectively; The median overall survival time was 16.0 months (range from 2 to 58 months). Among the 19 patients with abdominal pain or lower back pain, 12 (63.2%) achieved alleviation of pain symptoms after 3 times of treatment, 14 (73.7%) achieved complete remission at the end of treatment. Survival rate of patients with a total dose of ≥45 Gy treated with CyberKnife radiotherapy was significantly higher than that of patients with a total dose of <45 Gy, and there was significant difference between the 2 groups (P=0.000). The survival rate of patients without pain symptoms was significantly higher than that of patients with pain symptoms, and the difference was statistically significant (P=0.004). The incidence of gastrointestinal toxicities in Grade I and Ⅱ were 13.5％(5／37), no case appeared Grade III or above adverse events. Conclusion CyberKnife is safe and effective in the treatment of abdominal lymph node metastases of PHCC. CyberKnife stereotactic radiotherapy can effectively improve the survival rate and the local control rate, with less adverse reaction.

Key words: Primary hepatocellular carcinoma, Abdominal lymph node metastases, Cyberknife, Curative effect, Safety