To study the independent risk factors of tumor recurrence after radiofrequency ablation (RFA) in patients with hepatocellular carcinoma (HCC), and to establish a preoperative prediction score.

A retrospective study was conducted on 168 HCC patients treated with RFA at Zhongshan Hospital affiliated to Sun Yat-sen University from June 2016 to September 2019. The X-tile software was used to determine the optimal cut-off value of preoperative circulating tumor cells (CTC) which was then used to analyze the relationship between different CTCs values with various clinical factors. The Cox regression model was used to analyze independent risk factors of recurrence after RFA, and each independent risk factor was assigned a score of 1 to compose the prediction score. The patients were divided into the low-risk group (0-2 scores), intermediate-risk group (3 scores) and high-risk group (4-5 scores). The Kaplan-Meier method was used to draw cumulative recurrence curves in calculating the cumulative recurrence rates of the 3 different groups.

Of 168 patients, there were 151 males and 17 females. Their age (Mean±SD) was 58.33±9.53 years. CTC≥1/3.2 ml was detected in 131 patients (77.98%) (range 0-20/3.2 ml). The X-tile software determined the preoperative CTC cut-off value of HCC patients to be 2/3.2ml which separated a CTC-negative group with 93 patients, and a positive group of 75 patients. On analyses, the relationship between preoperative CTC and various preoperative clinical parameters were related to number of tumor nodules, tumor maximum diameter and alpha-fetoprotein (AFP) levels (P<0.05). Multivariate analysis showed that CTC positivity[HR(95%CI): 1.990(1.332-2.974)], AFP>20 ng/ml[HR(95%CI): 1.659(1.111-2.477)], PIVKA-II>40 mAU/ml[HR(95%CI): 1.580 (1.022-2.443)], number of tumor nodules ≥2[HR(95%CI): 1.568 (1.057-2.326)], and tumor diameter>30 mm[HR (95%CI): 1.544 (1.007-2.369)] were independent risk factors of recurrence (P<0.05) after RFA in HCC patients. The cumulative recurrence rates of patients at 6 months, 12 months, and 18 months were 14.9%, 35.6%, and 56.4% in the low-risk group, 38.9%, 70.5%, and 85.0% in the intermediate-risk group, and 64.5%, 84.5% and 100% in the high-risk group. The differences were significant (P<0.05).

Preoperative CTC positivity, AFP>20 ng/ml, PIVKA-II>40 mAU/ml, tumor nodules ≥2, and tumor diameter>30 mm were independent risk factors of recurrence after RFA in HCC patients. This preoperative predictive score could be used to guide clinical treatment strategies.

Carcinoma, hepatocellular; Radiofrequency ablation; Circulating tumor cells; Prediction score