Evaluation of Transarterial Chemoembolization Protocol with Drug-Eluting Beads in Combination with Lipiodol for Hepatocellular Carcinoma: A Single-Center Controlled Study

Objectives To evaluate the efficacy and safety of transarterial chemoembolization (TACE) with drug-eluting beads (DEB-TACE) and lipiodol (DEB-Lipiodol TACE) in the treatment of unresectable hepatocellular carcinoma (HCC) patients. Materials and Methods The medical records of consecutive unresectable HCC patients who underwent DEB-TACE or DEB-Lipiodol TACE from June 2016 to July 2021 were retrospectively evaluated. Therapeutic response, overall survival (OS), progression-free survival (PFS), and adverse events (AEs) were compared among the groups. Results Three hundred and twenty-seven patients were enrolled in the study, including 293 patients in the DEB-TACE group and 34 patients in the DEB-Lipiodol TACE group. The objective response rate in the DEB-Lipiodol TACE group was 17.6%, significantly higher than that in the DEB-TACE group (5.8%, P=0.011). Similarly, DEB-Lipiodol TACE group also had a higher disease control rate (91.2% vs 68.6%, P=0.006). Median OS was 13 months (95% CI: 11.0 months and 15.0 months) and 22 months (95% CI: 17.3 months and 26.7 months) in the DEB-TACE group and DEB-Lipiodol TACE group, respectively (P=0.041). Meanwhile, median PFS was 7 months (95% CI: 5.2 months and 8.8 months) in the DEB-TACE group and 12 months (95% CI: 7.9 months and 16.1 months) in the DEB-Lipiodol TACE group (P=0.174). There was no statistically significant difference in AEs incidence among the two groups (P > 0.05). Conclusions DEB-Lipiodol TACE was safe, well tolerated, and had a better efficacy compared with DEB-TACE in unresectable HCC patients.


Introduction
Transarterial chemoembolization (TACE) is the current frst-choice treatment in patients with intermediate-stage hepatocellular carcinoma (HCC) according to the Barcelona Clinic Liver Cancer (BCLC) staging system, especially those presenting with large or multifocal tumors with preserved liver function, deteriorated performance status, and portal vein thrombosis or extrahepatic metastases [1,2]. TACE improves survival in HCC patients by combining targeted chemotherapy with ischemic necrosis caused by arterial embolization [3,4]. Unfortunately, however, there is no agreement on how to proceed with TACE, with high variability in chemotherapeutics and embolization modalities, and no clear evidence of the superiority of a particular embolic material or drug [5,6].
Nearly 40 years ago, conventional TACE (cTACE) was introduced as a treatment modality for unresectable HCC. cTACE is a combination of lipiodol and chemotherapeutic drugs injected into the tumor-supplying artery, with lipiodol acting as a contrast agent and an embolization agent. However, chemotherapeutic drugs spread rapidly from the mixture, so the visualized area does not refect their distribution. Furthermore, the low mechanical strength of lipiodol leads to tumor arteries' recanalization because it is quickly cleared by blood scouring [7]. To overcome the drawbacks of cTACE, drug-eluting beads (DEBs) are designed to selectively deliver large amounts of chemotherapeutic drugs into the tumor over an extended period of time, minimizing the drug's blood concentration and associated systemic efects [8,9]. However, two prospective randomized studies demonstrated that DEB-TACE did not show an advantage over cTACE in terms of radiological response and clinical outcomes [10,11]. DEBs have poor fowability and are difcult to infltrate into tumor peripheral arteries, leading to the reconstruction of tumor collateral circulation, which may be the main reason affecting the efcacy of DEB-TACE in the treatment of unresectable HCC [12]. Taken together, it is urgent to explore new embolization methods to address the challenges of peripheral arterial embolization and drug-controlled release.
Since lipiodol can rapidly difuse into the peripheral tumor arteries and disrupt the blood supply of tumors by the formation of viscous oil/water emulsion with plasma [12], in this study, after DEBs embolization of the targeting arteries, we observed that lipiodol could still difuse into the peripheral tumor arteries. However, as far as we know, no studies have reported DEBs combined with lipiodol (DEB-Lipiodol) embolization for unresectable HCC. Tus, the purpose of this study is to evaluate the efcacy and safety of DEB-Lipiodol in the treatment of unresectable HCC.

Study Design and Patient Selection.
Te present retrospective, single-center study was conducted in accordance with the principles of the Declaration of Helsinki, and all procedures performed in this study were approved by the local hospital ethics committee. Written informed consent was obtained from all patients prior to treatment.
We analyzed the electronic medical records of 403 consecutive patients with unresectable HCC who received treatment with DEB-TACE or DEB-Lipiodol TACE at our center between June 2016 and July 2021. Te diagnosis of HCC depended on the diagnostic criteria of the European Association for the Study of Liver and the American Association for the Study of Liver Disease [2,13]. Te TACE treatment regimen was nominated by the multidisciplinary tumor board prior to initial TACE treatment in these patients. Meanwhile, the choice of the TACE technique (DEB-TACE or DEB-Lipiodol TACE) depends entirely on the operator's experience and preference at the time of treatment.
Te inclusion criteria of this study were as follows: (1) age >18 years old; (2) Child-Pugh class A or B. Exclusion criteria were as follows: (1) patients had been treated with previous surgical, locoregional, and/or systemic treatments; (2) hepatic dysfunction or renal impairment; (3) patients have other malignancies besides HCC; (4) medical records are related to hospitalization for the initial TACE treatment, 1 month of radiological and clinical follow-up, and/or clinical data deemed sufcient for statistical analysis were not available.

TACE Protocol.
TACE was performed based on our institutional standard protocol and has been described previously [14,15], and it was consistent with the standard chemoembolization protocol for hepatocellular carcinoma [16]. Briefy, under local anesthesia, 5-F catheter or 2.4-F microcatheter was selected to insert the tumor-supplying arteries according to the condition of the liver and vascular anatomy. For DEB-TACE, CalliSphere beads (Jiangsu Hengrui Medicine Co., Ltd., China) of diferent sizes (usually 100-300 μm) were loaded with epirubicin in 80 mg per vial. Te nonionic contrast agent was then added to the solution, and the mixture was slowly injected into the target vessels. In this study, a maximum of two vials were used per patient. If necessary, further embolization was performed with blank microspheres until the fow was near stasis. For DEB-Lipiodol TACE, like DEB-TACE, DEBs were frst injected into the target vessels, and then, lipiodol (mixed with epirubicin) was slowly injected. In order to improve the efect of embolization, further reduce the damage to normal liver tissue, and protect the liver function of patients, a microcatheter under 3F is usually used to superselect the branch of the supplying artery for embolization. After embolization, reexamination angiography of the hepatic artery was performed to confrm the devascularization.

Follow-Up and Repeated TACE.
All patients were followed-up until 31 August 2021. Laboratory tests and abdominal contrast-enhanced CT or MR were performed 6-8 weeks after the initial TACE. Follow-up CT or MR (approximately 6-8 weeks after initial TACE) was compared with preoperative imaging to determine the objective tumor radiologic regression (ORR) and disease control rate (DCR) in the liver according to modifed response evaluation criteria in solid tumors [17]. ORR was defned as complete response (CR) or partial response (PR). DCR was defned as CR, PR, or stable disease (SD). TACE was repeated if patients are with intrahepatic residual viable tumor or recurrent tumor on contrast-enhanced CT or MR images and with preserved liver function. Follow-up of all patients was conducted at a 6-8-week interval after the previous TACE.

Defnition and Evaluation of Data.
Overall survival (OS) referred to the time interval between the initial TACE and the date of death or last follow-up. Progression-free survival (PFS) referred to the period between the date of initial TACE and the date of progression for patients. Adverse events (AEs) were recorded and assessed by the Common Terminology Criteria for Adverse Events Version 5.0. In addition, postembolization syndrome, such as fever, pain, nausea, and vomiting, is not considered an AE in itself, but rather an expected outcome of embolization therapy [18].

Statistical
Analyses. All analyses were performed by using SPSS software, Version 24.0 (IBM, Armonk, New York). Categorical data were represented by numbers with percentages and calculated using the chi-squared test. Continuous variables were presented as mean ± standard deviation and calculated using Student's t-test. OS and PFS were plotted by using the Kaplan-Meier method. Log-rank test was used for univariate analysis, in which variables with P value less than 0.10 in univariate analysis were added to multivariate analysis. P < 0.05 indicated a statistically signifcant diference. Te receiver operating characteristic (ROC) curve analysis was performed to demonstrate the diagnostic signifcance of hypertransaminasemia for tumor response.

Study Population and Patient
Characteristics. From June 2016 to July 2021, a total of 403 unresectable HCC patients received either DEB-TACE or DEB-Lipiodol TACE in our study. Of these, 76 patients were excluded because they did not meet the study requirements, as shown in Figure 1. Finally, 327 patients were enrolled in the study, 293 receiving DEB-TACE and 34 receiving DEB-Lipiodol TACE. Tere were no signifcant diferences in baseline characteristics between the two groups, and detailed baseline demographics and characteristics of the 327 patients were summarized in detail in Table 1.
In the DEB-TACE group, AEs occurred after embolization in 36 patients. Eight patients developed grade 1 liver abscess, 11 patients developed grade 2 liver abscesses, and 3 patients developed grade 3 liver abscesses, which subsided after abscess drainage and antibiotic treatment. In addition, 7 patients developed grade 1 biloma, and 4 patients developed grade 2 biloma. Tree patients died of liver and kidney failure 1-3 days after embolization. In the DEB-Lipiodol TACE group, AEs occurred after embolization in 5 patients, and there was no statistically signifcant diference in AEs incidence between the two groups (P > 0.05). Two patients developed grade 3 liver abscesses, which disappeared after symptomatic treatment. Tree patients developed grade 2 biloma, which improved after drainage. Tere were no TACE-related deaths in this group.

Treatment Response.
In the DEB-TACE group, 1 patient achieved CR, 16 patients achieved PR, and 184 patients achieved SD. Hence, the ORR and DCR were 5.8% and 68.6%, respectively. In the DEB-Lipiodol TACE group, 1 patient achieved CR, 5 patients achieved PR, and 25 patients achieved SD. Tus, the ORR and DCR were 17.6% and 91.2%, respectively. Terefore, the ORR (P � 0.011) and DCR (P � 0.006) of the DEB-Lipiodol TACE group were signifcantly better than those of the DEB-TACE group.

Progression-Free Survival.
In the DEB-TACE group, the median PFS was 7 months (95% CI: 5.2 months and 8.8 months). In the DEB-Lipiodol TACE group, the median PFS was 12 months (95% CI: 7.9 months and 16.1 months) (Figure 3), and there was no signifcant statistical diference between the two groups (P � 0.174). Univariate analysis (Table 2) indicated that the BCLC stage, aspartate aminotransferase, PLR, NLR, tumor size, and TACE sessions were associated with PFS. Ten, through multivariate analysis (Table 4), we found that BCLC stage and TACE sessions were independent prognostic factors afecting PFS.
3.6. ROC Analysis. ROC analysis was performed on the correlation between these changes and objective remission. Te results showed that no correlation was found between the objective response and post-treatment transient transaminase elevation (P � 0.787 and P � 0.389, respectively) ( Figure 4). In addition, there was no signifcant correlation between postoperative hyperaminotransferemia and objective radiologic response in the D-TACE group and the DEB-Lipiodol TACE group (Figures 5 and 6).

Discussion
Te present study yielded a major fnding that we were able to demonstrate a positively potentiating efect of the additional use of lipiodol compared to DEB-TACE alone for unresectable HCC. Te results of this study showed that compared with the DEB-TACE group, the DEB-Lipiodol TACE group had a better tumor response and a greater survival beneft.

Journal of Oncology 3
To compensate for the defciency of cTACE, DEBs were developed to achieve controlled drug release and permanent vascular embolization. However, DEBs have poor fowability and are difcult to infltrate into tumor peripheral arteries, often leading to incomplete tumor embolization [12]. Insufcient embolization is known to lead to elevated levels of hypoxia in tumor tissue, which often leads to tumor angiogenesis, metastasis, and recurrence [19,20]. Two previous prospective randomized studies also showed no signifcant diference in therapeutic efcacy between DEB-TACE and cTACE. Hence, in order to improve the efcacy of DEB-TACE in the treatment of unresectable HCC, DEBs and lipiodol were combined in this study to achieve complete embolization of tumor peripheral vessels. As indicated by the theoretical advantages, the ORR and DCR of the DEB-Lipiodol TACE group were signifcantly higher than those of the DEB-TACE group in this study, indicating that combined DEBs and lipiodol embolization can increase the rate of radiological response.
In terms of the impact of radiological response on OS, the radiological response was associated with longer OS. In the present study, DEB-Lipiodol TACE was associated with a higher rate of tumor response and increasing OS compared to DEB-TACE. Tis beneft in survival outcomes suggests that radiological response is one of the important determinants of long-term survival. Terefore, to put the results of this study into a clinical context, a combination of lipiodol and DEBs as an embolization regimen may be preferable to DEBs alone for patients requiring TACE as therapy of HCC. Meanwhile, the experience of the operator, local circumstances, and availability should be taken into consideration.
It has been reported that AEs were similar or decreased in DEB-TACE than cTACE, especially that the incidence of postembolization syndrome was reduced in DEB-TACE procedures [10,11]. While in systematic reviews, AEs of DEB-TACE were similar to those of c-TACE, including postembolic syndrome [21][22][23], suggesting that DEB-TACE is safe. In this study, except for 3 patients in the DEB-TACE group who died of liver and kidney failure, only a few patients developed grade 1-3 AEs, and all of them improved with symptomatic treatment. Furthermore, there were no deaths in the DEB-Lipiodol TACE group and no diference in AEs incidence between the two groups, suggesting that the DEB-Lipiodol TACE group is also safe.
Recent studies have shown that the infammation ratio of PLR may potentially serve as a quantitative biomarker for individual tumor characteristics [24,25]. A study [26] investigated infammatory biomarkers in patients with HCC treated with TACE and found that high baseline PLR predicted poorer tumor response and shorter PFS. Meanwhile, two other studies [27,28] also reported that high PLR is associated with poorer OS and metastasis in HCC patients treated with TACE. In this study, multivariable analysis showed that PLR was an independent prognostic factor afecting OS. Hence, baseline PLR may be important factor afecting prognosis.
Also, note that in Table 1   Journal of Oncology in patients with liver cancer and cirrhosis [29], which used Child-Pugh-Turcott (CPT) to grade liver function. TACE therapy is currently considered inappropriate for patients with hepatic decompensation, i.e., CPT B ≥8 (the presence of ascites or hyperbilirubinemia, or both), due to the high risk of severe postoperative complications. In this study, there were a total of 7 patients with CPT B ≥8 in the two groups (5 patients in the D-TACE group and 2 patients in the DEB-Lipiodol TACE group). Fortunately, no postoperative adverse events occurred in the above 7 patients after TACE treatment. Terefore, we believe that some HCC patients can receive TACE therapy under the close supervision of clinicians, even if the CPT B score ≥8. In addition, we believe that the factors afecting the therapeutic efect of TACE and the occurrence of postoperative adverse events are not only these fve factors but also related to the degree of cirrhosis and tumor blood supply. As mentioned in this article, when evaluating whether CPT B HCC patients can receive TACE treatment, not only the liver function reserve but also other factors of the patient should be considered. In addition, transient hyperaminotransferemia after cTACE has been shown to be signifcantly associated with objective treatment response [30]. Tis is inconsistent with the results of this study, and we speculate that it may be related to the sample size, the patient's HCC risk factors, and baseline liver function. Terefore, multicenter, large-sample studies are necessary to evaluate the relationship between transient hyperaminotransferemia and objective treatment response.
Our study has several limitations. First, the present study was conducted in a single institution with a small sample size, and therefore, a multicenter prospective randomized trial is needed to validate the results of this study. Second, patients and tumors may have diferent characteristics in diferent countries. Larger studies or meta-analyses in different regions may be required to demonstrate the efcacy of

Conclusion
In conclusion, this study indicated that DEB-Lipiodol TACE was able to achieve better tumor response and survival benefts in unresectable HCC patients compared with DEB-TACE. Meanwhile, DEB-Lipiodol TACE was also safe and well tolerated for HCC patients, with no severe AEs observed. Hence, on the basis of our fndings, DEB-Lipiodol TACE may be a potential new embolization treatment option for unresectable HCC patients. However, further prospective randomized controlled trials are needed to validate our observations. Overall survival PFS: Progression-free survival AEs: Adverse events.

Data Availability
Te data analyzed during this study are available from the Electrical Medical Database of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology. Te data are available from the author Chuansheng Zheng upon reasonable request.

Ethical Approval
Tis retrospective study was approved by the Institutional Review Board of the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.

Consent
Written informed consent was obtained from all patients prior to treatment.