The course and prognostic value of tumor stiffness detected by ultrasound elastography for transarterial chemoembolization of hepatocellular carcinoma.

Background: Transarterial chemoembolization (TACE) is recommended as the first-line treatment in intermediate-stage patients with hepatocellular carcinoma (HCC) or as a palliative treatment modality in advanced patients. However, tumor control usually requires multiple TACE interventions due to the presence of residual and recurrent lesions. Elastography can provide information about tumor stiffness (TS) to predict tumor residual or recurrence. In this study, we aimed to analyze the effects of TACE on HCC stiffness using ultrasound elastography (US-E). We investigated whether quantifying TS using US-E could predict the recurrence of HCC. Methods: This retrospective cohort study included 116 patients undergoing TACE to treat HCC. US-E was performed to measure the tumor's elastic modulus within 3 days before TACE, in the 2 days after the intervention, and at the 1-month follow-up. The known prognostic factors of HCC were also analyzed. Results: The average TS before TACE was 40.1±14.36 kPa, and the average TS 1 month after TACE was 19.3±9.80 kPa. The mean progression-free survival (PFS) was 39.129 months, and the 1-, 3-, and 5-year PFS rates were 81.0%, 56.9%, and 37.9%, respectively. The mean overall survival (OS) was 48.552 months, and the 1-, 3-, and 5-year OS rates of patients with malignant hepatic tumors were 95.7%, 75.0%, and 49.1%, respectively. Tumor number, tumor location, TS before TACE, and TS 1 month after TACE were significant predictive factors for OS (P=0.02, P=0.03, P<0.001, and P<0.001, respectively). Rank correlation analysis and linear regression revealed that a higher TS before or 1 month after TACE was negatively associated with PFS. The reduction ratio in TS before and 1 month after therapy was positively associated with PFS. The optimal cutoff TS value was set at 46 and 24.5 kPa before and 1 month after TACE according to the optimal Youden index. Kaplan-Meier survival analyses demonstrated that the 2 groups had significant differences in OS and PFS and that a higher TS was positively correlated with OS and PFS. Conclusions: Our results verify that US-E provides additional information to characterize the tumoral stiffness of HCC. These findings indicate that US-E is a valuable tool for evaluating the tumor response after TACE therapy in patients. TS can also be an independent prognostic factor. Patients with a high TS had a higher risk of recurrence and a worse survival time.