Comparison of Efficacy and Safety of TACE Combined with Microwave Ablation and TACE Combined with Cryoablation in the Treatment of Large Hepatocellular Carcinoma.

Purpose: To retrospectively evaluate the efficacy and safety of TACE combined with microwave ablation (MWA) and TACE combined with cryoablation (CRA) in the treatment of large hepatocellular carcinoma.
Methods: A retrospective analysis was performed on 81 patients with large hepatocellular carcinoma (tumor diameter 5～8 cm cm) who received TACE combined with ablation in our hospital from February 2015 to February 2019. The study patients were divided into TACE combined with MWA group (T-MWA, n = 41) and TACE combined with CRA group (T-CRA, n = 40) according to the treatment plan. Overall survival (OS) and progress free survival (PFS) were compared between the two groups, and complications were observed. Survival curves for OS and PFS were constructed by the Kaplan-Meier method. Differences in overall survival were compared using the log-rank test.
Results: There was no statistical difference in general conditions between the two groups of patients. The results showed that 30 (73.2%) patients in T-MWA group achieved objective response (OR) and 39 (95.1%) patients achieved disease control (DC), compared with 24 (60.0%) patients in T-CRA group who achieved objective response (OR) and 37 (92.5%) patients who achieved disease control (DC). The median OS was 19.2 months in the T-MWA group and 18.6 months in the T-CRA group (P=0.64). The median PFS was 9.3 months in the T-MWA group and 12.3 months in the T-CRA group (P=0.6). Univariate and multivariate analysis showed that portal vein tumor thrombus (PVTT), intrahepatic tumor diameter, and the number of tumor lesions were common prognostic factors for OS and PFS. In terms of surgery-related complications and adverse reactions, abdominal pain and gastrointestinal reactions were observed in 13 (31.7%) and 11(26.8%) cases in the T-MWA group, while we observed 4 (10.0%) and 2 (5.0%) cases in the T-CRA group, respectively. The difference between the two was statistically significant (P < 0.05).
Conclusion: TACE combined with MWA and TACE combined with CRA were equally effective in the treatment of large hepatocellular carcinoma. TACE-CRA can effectively reduce the incidence of abdominal pain and gastrointestinal reactions in patients. However, compared with TACE-MWA, TACE-CRA is more likely to cause thrombocytopenia.

1. Introduction

Liver cancer is currently the sixth most common malignancy in the world and has developed into the fourth most common cause of cancer death. Among them, Hepatocellular carcinoma HCC is the most common pathological type of liver cancer, accounting for about 90% of all pathological types. In terms of Pathology, we usually call liver cancer with a diameter of ≥5 cm under the naked eye as large liver cancer. This type of liver cancer is the most common and difficult to remove by surgery [1, 2]. At present, surgical resection is still the preferred treatment for patients with liver cancer who have no obvious surgical contraindications, However, because there are no specific clinical symptoms in the early stage of HCC, it is difficult to diagnose early, so the first diagnosis of liver cancer patients Less than 20% are able to receive surgical treatment [3]. For patients who are not suitable for surgery, alternatives to surgery mainly include transcatheter arterial chemoembolization (TACE) and a variety of ablation techniques, including microwave ablation (MWA), cryoablation (CRA), Radiofrequency ablation (radiofrequency ablation, RFA), and so on [4]. TACE is an interventional treatment method for liver cancer in which chemotherapeutic drugs are directly injected into the blood supply artery of the tumor through a catheter, and the blood supply to the tumor is blocked with an embolic material. Currently, TACE is considered as a first-line treatment modality for BCLC stage B HCC according to the Barcelona Clinic Liver Cancer stage guidelines [5]. However, it is difficult to embolize all the blood supply arteries of the tumor during TACE, and there is the possibility of recanalization or regeneration of blood vessels after TACE, which promotes the recurrence and metastasis of the tumor and may promote the establishment of new collateral circulation in the blood supply arteries of the tumor, which makes the treatment of liver cancer with TACE alone limited and insufficient [6]. With the continuous development and improvement of percutaneous ablation technology, its curative effect is more and more worthy of affirmation, especially for small liver cancer ≤3 cm, the curative effect of ablation is equivalent to that of surgical resection [7]. Thanks to the continuous progress of current tumor ablation technology, the treatment scheme of TACE combined ablation for liver cancer has attracted extensive attention in recent years, and the combined therapy has been proven to significantly improve the curative effect and prolong the survival time of patients [8]. Especially for large HCC more than 5 cm, the curative effect of simple ablation is not accurate, and some studies have shown that the combined therapy is safe and effective for large HCC, and the tumor progression rate is lower than that of monotherapy. At this stage, there are still some controversies about the advantages and disadvantages of the above two regimens in the treatment of large liver cancer. Therefore, this study aimed to compare and analyze the efficacy and safety of TACE combined with MWA and TACE combined with CRA in large liver cancer and comprehensively analyze the obtained statistical data to provide data support for the optimization and improvement of the later clinical treatment plan for large liver cancer.

2. Materials and Method

2.1. Clinical Information

In this study, the clinical data of 81 patients with large liver cancer admitted to our hospital from February 2015 to February 2019 were selected for retrospective analysis. The inclusion criteria are as follows. ① According to the diagnostic criteria of liver cancer in AASLD guidelines, combined with the clinical or pathological data of the patients, the maximum diameter of the tumor measured according to enhanced CT or enhanced MRI images is 5∼8 cm [9]; ② Surgical treatment such as surgical resection or liver transplantation is not recommended after multidisciplinary consultation in the hospital; ③ Child Pugh grade A and B of liver function; ④ PS score 0–2; ⑤ There was no intervention, chemoradiotherapy, immunization, and surgical treatment within 1 month before treatment. The exclusion criteria were as follows: ① Child pugh grade of liver function, including severe jaundice, hepatic encephalopathy, and refractory ascites; ② Severe coagulation dysfunction and difficulty to correct; ③ The peripheral blood cells of patients decreased significantly due to chemotherapy, hypersplenism, and other reasons, such as white blood cell count <3.0 × 109/L, platelet count <50.0 × 109/L; ④ The main portal vein was embolized, and the collateral circulation was not perfect; ⑤ Complicated with serious basic diseases and unstable disease control; ⑥ The follow-up cannot be completed on schedule, or the follow-up data are incomplete or missing; ⑦ Liver function child-PughC grade; ⑧ with active infection, especially biliary tract infection.

2.2. Experimental Grouping and Surgical Plan

2.2.1. Experimental Grouping

Among the 81 cases included in the experiment, 41 patients with liver cancer treated with TACE combined with MWA were regarded as t-mwa group, and the other 40 patients with liver cancer treated with TACE combined with CRA were regarded as t-cra group; Inform the patients and their authorized clients of the advantages and disadvantages of different treatment methods before the operation, including the expected curative effect, possible complications, operation risks, and expenses. The choice of treatment scheme is finally voluntary by the patients and their authorized clients. All operations have signed the informed consent of interventional therapy.

2.2.2. Treatment Solutions

After admission, all patients completed routine preoperative examinations including biochemistry, coagulation, and blood routine, etc., and then two physicians with more than 10 years' experience in interventional therapy performed a standard TACE treatment: After routine disinfection, laminating, 2% lidocaine local anesthesia, the modified Seldinger technique was used for femoral artery puncture to open the vascular approach, and guide wire and 5F RH catheter were introduced. Firstly, the celiac trunk, superior mesenteric artery, and diaphragmatic artery were selected for angiography, and the location of tumor supplying artery was determined. The 2.7f RAPIDTHRU®microcatheter guide wire system (Hengri medical, Lianyungang city, Jiangsu province) was routinely introduced to perform superselective selection of the blood supply artery. First, 2.0 mg/m2 of RAPIDTHRU and 50 mg/m2 of lobaplatin were mixed with superliquid iodide oil and then fully emulsified. The amount of iodide oil was estimated according to the size of the tumor (1–3 ml/cm). The dose is less than or equal to 20 ml, and lipiodol is slowly injected into the embolization of the tumor supplying artery. According to the patient's tumor blood supply, the choice of embolization microsphere intervention can help reduce the tumor blood supply.

Two weeks later, the patients who had undergone one TACE treatment were reexamined, including biochemistry, coagulation, and blood routine examination, etc. At the same time, a CT examination was performed to observe the lipiodol deposition. Patients who had no obvious contraindications and voluntarily accepted further ablation were given one ablation.

For patients in the T-MWA group, a standard CT-guided MWA treatment was given, ablation was usually performed under local anesthesia, and analgesics were usually given before or during surgery to patients who could not tolerate pain. Intraoperative microwave therapy instrument (Nanjing Yigao Medical Instrument Co., LTD., Jiangsu Province). Output power: The number of ablation needles was reasonably selected according to the location, size, and shape of the lesion. When multiple needles were combined, they were arranged at a proper spacing of 1.5∼2.0 cm to ensure that the ablation area covered more than 1 cm at the edge of the lesion. The ablation time was determined by the size of the lesion and adjacent organs, and the single point ablation time was usually 5∼10 min. Intraoperative CT scan was performed to detect the ablation range. For patients in t-CRA group, a standard CRA treatment was given, also cT-guided, under local anesthesia. According to the location, size, and shape of the lesion, the number of ablation needles was reasonably selected. In the multineedle combination scheme, the appropriate pattern was arranged according to the spacing of 3–3.5 cm. The cryogenic surgical system AH-1 (Shenyang Medical Innovation Technology Co., LTD., Liaoning Province) was started. First, the temperature around the ablation needle was lowered to below −150°C, and the duration of cryoablation was determined according to the size of the lesion, which generally lasted 10∼15 min. Then CT scan monitoring was performed. Then continue to rewarm to 20°C∼30°C and repeat the above cold-heat cycle. Plain CT scan should be performed after ablation to ensure that the ablation range covers the tumor lesion and the surrounding normal liver tissue of 1 cm.

2.3. Observation Indicator

To the starting point of combination therapy for postoperative follow-up, in patients with death or the end of the follow-up time as the end of follow-up, the main form of follow-up for outpatient care, secondary form for follow-up telephone or other communications, instruct patients on postoperative 1∼2 months in the hospital outpatient reviewed for the first time, instead of 2∼3 months after the first review a review and follow-up of 3 years, During the follow-up review, the results were evaluated, and those requiring further treatment were given further treatment.

2.3.1. General Clinical Information

The differences in gender, age, PS score, liver function grade, ascites, tumor diameter, portal vein invasion, and other baseline characteristics between the two groups were observed.

2.3.2. Short-Term Efficacy

The efficacy was evaluated according to enhanced CT or MRI during the first outpatient review, and the Evaluation method is referred to as the Modified Response Evaluation Criteria in Solid Tumors (mRECIST) [10]. Complete response (COM-plete response, CR): all target lesions disappeared; Partial response (PAR-tial response, PR): the total diameter of target lesions before treatment was reduced by at least 30%. Progressive disease (PD): the sum of the diameter of the target lesions before treatment is taken as a reference, and the sum of the diameter of the target lesions increases by at least 20% or new lesions appear; Stable disease (SD): the reduction of target lesion diameter did not reach PR, and the increase did not reach PD. Objective Response Rate (ORR) and disease control rate (DCR), wherein ORR includes all cases of OR and PR, while DCR includes all cases of OR, PR, and SD.

2.3.3. Long-Term Efficacy

The patients were followed up regularly after treatment, and their Overall Survival (OS), Progress Free Survival (PFS), and 1-, 2-, and 3-year survival rates were recorded. OS was defined as the period from the beginning of TACE treatment to the end of patient death or follow-up, while PFS was defined as the period from the beginning of TACE treatment to the occurrence of tumor progression or death.

2.3.4. Complication

Surgical complications were recorded according to regular follow-up results after combination therapy, and surgery-related complications were assessed according to criteria defined by the Complication classification system of the European Society of Cardiovascular and Interventional Radiology (CIRSE). Level 2: requiring hospitalization for observation, but resulting in a prolonged stay of less than 48 hours, requiring no additional treatment, and with no sequelae; Level 3: requiring additional hospitalization for observation >48 hours, or requiring additional treatment, without sequelae; Grade 4: complications lead to mild permanent sequelae (normal function can be restored after treatment without affecting the independent living of patients); Level 5: severe permanent sequelae (inability to live independently); Grade 6: Patients die, with grade 1–2 as mild complications and grade 3–6 as major complications [11].

2.4. Statistical Methods

Statistical software SPSS 26.0 (IBM SPSS, Chicago, IL) was used for statistical analysis. Shapiro–Wilk normality test was used to determine normality. If normal distribution was not met, median (quartile spacing) was used for description. If normal distribution is satisfied, mean ± standard deviation is used for description, and t-test is used. Count data were described by frequency (percentage), and a chi-square test was used to analyze differences between groups. The survival curves of OS and PFS were constructed by the Kaplan–Meier method. Survival analysis used the log-rank test to compare differences in overall survival. Cox regression model was used to conduct univariate and multivariate analysis on the related variables of the enrolled patients. Multivariate analysis was performed on all the variables assessed by univariate analysis with P < 0.05, so as to analyze the significance of related variables in predicting OS and PFS. The hypothesis test was conducted as a two-sided test and P < 0.05 was considered statistically significant.

3. Results

3.1. Baseline Characteristics

The baseline characteristics of the two groups are shown in Table 1. A total of 81 patients with unresectable large liver cancer were included, including 52 males and 29 females. The average age was 58.48 ± 8.43 years; PS score: 0 in 42 cases, 1∼2 in 39 cases; Liver function score: GRADE A 64 cases, grade B 17 cases; There were 56 cases without portal vein invasion and 25 cases with portal vein invasion. There were 40 cases of single tumors and 41 cases of multiple tumors. The maximum diameter of tumors was 5–10 cm in 49 cases and >10 cm in 32 cases. There was no significant difference in baseline characteristics between the two groups (P > 0.05).

Table 1

Comparison of baseline characteristics of study patients.

Characteristics	T-MWA group	T-CRA group	P-value
	n = 41	n = 40
Age(years)	57.3 ± 9.81	59.70 ± 6.66	0.568
＞58	21(51.2)	24(60.0)
≤58	20(48.8)	16(40.0)
Gender			0.585
Male	28(68.3)	24(60.0)
Female	13(31.7)	16(40.0)
PS			0.858
0	21(51.1)	21(52.5)
1	18(43.9)	16(40.0)
2	2(4.9)	3(7.5)
Etiology			0.513
HBV	36(87.8)	32(80.0)
Other	5(12.2)	8(20.0)
Cirrhosis			0.478
Yes	29(70.7)	32(80.0)
No	12(29.3)	8(20.0)
Tumor number			0.74
Single	19(46.3)	21(52.5)
Multiple	22(53.7)	19(47.5)
Child-Pugh class			1.000
A	32(78.0)	32(80.0)
B	9(22.0)	8(20.0)
AFP level (ng/ml)			0.719
≤400	23(56.1)	25(62.5)
>400	18(43.9)	15(37.5)
PVTT statue			0.941
Yes	12(29.3)	13(32.5)
No	29(70.7)	27(67.5)
ALT (U/L)	27.00 [20.00,44.00]	27.50 [21.00,48.00]	0.688
AST (U/L)	37.00 [28.00,45.00]	35.50 [26.75,47.25]	0.932
Albumin (g/L)	38.60(4.49)	37.24(4.98)	0.199
Total bilirubin (μmol/L)	17.30 [13.30,23.90]	15.00 [11.43,21.33]	0.236

Note. T-MWA: TACE Combined With microwave ablation; T-CRA: TACE Combined With radiofrequency ablation.

3.2. Recent Clinical Efficacy

The enhanced CT results of the first outpatient review 1∼2 months after the combined treatment were evaluated (Table 2). CR was observed in 5(12.2%) patients in the T-MWA group and 2(5.0%) patients in the T-CRA group. PR was achieved in 25 (61.0%) patients in the T-MWA group and 22(55.0%) patients in the T-CRA group. It can be concluded that 30 (73.2%) patients in the T-MWA group achieved an objective response, while 24(60.0%) patients in the T-CRA group achieved an objective response. In addition, 39 (95.1%) patients in the T-MWA group achieved disease control, while 37(92.5%) patients in the T-CRA group achieved disease control, and there was no statistical significance between the two groups (P > 0.05).

Table 2

Comparison of recent clinical efficacy.

Parameters	T-MWA group	T-CRA group	P-value
	(n = 41) n(%)	(n = 40) n(%)
CR	5(12.2)	2(5.0)	0.449
PR	25(61.0)	22(55.0)	0.749
SD	9(22.0)	13(32.5)	0.414
PD	2(4.9)	3(7.5)	0.977
ORR	30(73.2)	24(60.0)	0.307
DCR	39(95.1)	37(92.5)	0.977

Note. T-MWA: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation; CR: Complete response; PR: Partial response; SD: Stable disease; PD: Progressive disease; ORR: Objective response rate; DCR: Disease control rate.

3.3. Long-Term Clinical Efficacy

Long-term efficacy was evaluated according to follow-up results of patients (Table 3). The median OS and PFS were 19.2 months and 9.3 months in the T-MWA group and 18.6 months and 12.3 months in the T-CRA group. The 1-year, 2-year, and 3-year survival rates in the T-MWA group were 82.9%, 43.3%, and 22.6%, respectively, while the 1-year, 2-year, and 3-year survival rates in the T-CRA group were 77.5%, 35.0%, and 20.0%, respectively. There was no statistical difference in the 3-year survival rates between the two groups (P > 0.05). The survival curves of OS and PFS were constructed by Kaplan–Meier method, as shown in Figures 1–6. There was no statistically significant difference in OS and PFS between the two groups (P > 0.05). Cox regression model was used for univariate and multivariate analysis of the variables related to the enrolled patients, as shown in Tables 4 and 5. The results showed that the number of lesions and PVTT were statistically significant prognostic factors for OS, while gender, number of lesions, and PVTT were statistically significant prognostic factors for PFS (P < 0.05).

Table 3

Comparison of Long-term clinical efficacy.

Parameters	T-MWA group	T-CRA group	P-value
	(n = 41)%	(n = 40)%
OS
1 year	82.9% (41)	77.5% (31)	0.593
2 years	43.3% (18)	35.0% (14)	0.587
3 years	22.6%	20.0%	0.643
Median OS (month)	19.2	18.6
PFS
1 year	43.9% (18)	55.0% (22)	0.254
2 years	22.0% (90)	18.3% (7)	0.721
3 years	4.9%	5.2%	0.603
Median PFS (month)	9.3	12.3

Note. T-MWA: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation; OS: overall survival; PFS: progress free survival.

Figure 1

1-year OS survival curve.

Figure 2

Two-year OS survival curve.

Figure 3

3-year OS survival curve.

Figure 4

1-year FPS survival curve.

Figure 5

2-year FPS survival curve.

Figure 6

3-year FPS survival curve. Note: T-MW A: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation; OS: overall survival; PFS: progress free survival.

Table 4

Prognostic factors associated with overall survival.

Factor	Univariate analysis		Multivariate analysis
	HR(95% CI)	P-value	HR(95% CI)	P-value
Age (8 vs. ≤58)	1.598(0.963∼2.653)	0.071	—	—
Gender (male vs. female)	1.442(0.858∼2.423)	0.165	—	—
PS (0 vs. 1–2)	1.145(0.700∼1.880)	0.582	—	—
Etiology (HBV vs. Other)	1.133(0.577∼2.233)	0.711	—	—
Cirrhosis (yes vs. no)	0.860(0.491∼1.501)	0.589	—	—
Tumor number (multiple vs. Single)	1.889(1.144∼3.129)	0.014	1.968(1.138∼3.396)	0.017
Child-Pugh class (A vs. B)	1.070(0.589∼1.943)	0.820	—	—
AFP level (>400 vs. ≤400)	1.042(0.628∼1.723)	0.871	—	—
PVTT statue (yes vs. no)	3.845(2.248∼6.552)	<0.001	4.251(2.360∼7.648)	<0.001
Treatment (T-MWA vs. T-CRA)	1.121(0.684∼1.843)	0.642	—	—

Note. T-MWA: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation.

Table 5

Prognostic factors associated with progress free survival.

Factor	Univariate analysis		Multivariate analysis
	HR(95% CI)	P-value	HR(95% CI)	P-value
Age (years) (>58 vs. ≤58)	1.448(0.915∼2.293)	0.114	—	—
Gender (male vs. female)	1.681(1.042∼2.713)	0.033	2.165(1.301∼3.566)	<0.001
PS (0 vs. 1–2)	0.937(0.597∼1.470)	0.776	—	—
Etiology (HBV vs. Other)	0.888(0.485∼1.623)	0.698	—	—
Cirrhosis (yes vs. no)	0.732(0.435∼1.231)	0.239	—	—
Tumor number (multiple vs. Single)	2.137(1.321∼3.478)	<0.001	2.225(1.351∼3.664)	0.002
Child-Pugh class (A vs. B)	0.966(0.555∼1.681)	0.902	—	—
AFP level (>400 vs. ≤400)	0.827(0.520∼1.315)	0.422	—	—
PVTT statue (yes vs. no)	2.184(1.344∼3.549)	0.002	1.992(1.196∼3.320)	0.008
Treatment (T-MWA vs. T-CRA)	0.893(0.569∼1.401)	0.621	—	—

Note. T-MWA: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation.

3.4. Complications and Adverse Events

Grade 5 to 6 severe complications were not observed in any of the experimental groups. Fever was the most common complication in both groups, of which 13(31.7%) cases were observed in the T-MWA group and 18(45.0%) cases in the T-CRA group. There was no statistical significance between the two groups (P > 0.05). In the t-MWA group, 13(31.7%) and 11(26.8%) cases of postoperative abdominal pain and gastrointestinal reactions were more common, while in the T-CRA group, only 4 (10.0%) and 2 (5.0%) cases were observed. The difference between the two groups was statistically significant (P < 0.05). There is no significant difference in the incidence of ASCITES and intrahepatic hemorrhage between the two groups after surgery. Ascites were observed in the T-MWA group and the T-CRA group, respectively. Intrahepatic hemorrhage was observed in 4 (9.8%) patients vs. 5 (12.5%) patients, and intrahepatic hemorrhage was observed in 1 (2.4%) patients vs. 3 (7.5%) patients, with no significant difference between the two groups (P > 0.05). Thrombocytopenia was more common in the T-CRA group. A total of 12 (30.0%) thrombocytopenia patients were found, including 1 grade 3 thrombocytopenia patient who was discharged after positive symptomatic treatment without permanent sequelae. In addition, the incidence of liver abscess and liver dysfunction is low in all patients and only one liver abscess and liver dysfunction is found in the T-MWA group. Liver dysfunction was found in 2 patients in the T-CRA group, and there was no significant difference between the two groups (P > 0.05) (see Table 6).

Table 6

Complications and adverse events related to T-MWA and T-CRA

Complications	T-MWA group (n = 41) n(%)		T-CRA group (n = 40) n(%)		P-value
	Minor	Major	Minor	Major	Minor	Major
Fever	13(31.7)	0	18(45.0)	0	0.316	—
Abdominal pain	13(31.7)	0	4(10.0)	0	0.034	—
GR	11(26.8)	0	2(5.0)	0	0.007	—
Ascites	4(9.8)	0	5(12.5)	0	0.969	—
IH	1(2.4)	0	3(7.5)	0	0.59	—
Liver abscess	0	1(2.4)	0	0	—	1
Thrombocytopenia	2(4.9)	0	11(27.5)	1(2.5)	0.012	0.881
Liver dysfunction	0	1(2.4)	0	2(5.0)	—	0.983

Note. T-MWA: TACE combined with microwave ablation; T-CRA: TACE combined with radiofrequency ablation; GR: gastrointestinal reactions; IH: intrahepatic hemorrhage.

4. Discussion

Patients with large hepatocellular carcinoma have poor prognosis due to large tumor burden and severe vascular invasion, and no reliable radical cure has been developed at this stage. Currently, the combined application of TACE, ablation, radiotherapy, chemotherapy, and immunotherapy is a research hotspot [12]. In this study, 81 patients with large liver cancer were selected as the research subjects for retrospective analysis. They were divided into microwave ablation combined with conventional treatment group and conventional cryoablation group according to the treatment plan. The clinical efficacy and complication rate of the two groups were compared and statistically analyzed according to the follow-up results, and the conclusions were drawn. We found no statistically significant difference in ORR (30(73.2%) vs. 24 (60.0%), P=0.307) and DCR (39(95.1%) vs. 37 (92.5%) P=0.977) between the T-MWA group and the T-CRA group in terms of short-term efficacy. In terms of long-term efficacy, the patients were followed up for 3 years, and there were no statistically significant differences in 3-year cumulative survival, median OS (19.2 months vs. 18.6 months, P=0.64), or median PFS (9.3 months vs. 12.3 months, P=0.60) between the two groups. This suggests that the combination therapy of T-MWA and T-CRA seems to have the same efficacy in the treatment of large HCC. Univariate and multivariate analysis showed that the condition of portal vein tumor thrombus (PVTT) and the number of tumor lesions were common prognostic factors for OS and PFS. In terms of treatment-related complications and adverse events, we found that compared with patients in the T-MWA group, patients receiving T-CRA combination therapy had a lower probability of perioperative abdominal pain and gastrointestinal reactions but a higher probability of thrombocytopenia, with statistically significant differences between the two groups (P < 0.05).

Previous studies have confirmed that TACE combined with ablative therapy for liver cancer is more effective and can benefit patients more than single therapy [13-16]. In terms of combination therapy for large HCC, Zheng et al. retrospectively analyzed 258 large HCC patients who received TACE combined with MWA (n = 92) or TACE alone (n = 166) and found that for large HCC patients, compared with TACE alone, the combination therapy of TACE + MWA has more advantages in prolonging the survival of patients, and the progression-free survival of patients is longer [17]. Cui et al. enrolled 110 patients with large HCC and divided them into the TACE-CRA group (n = 56) and TACE group (n = 54) according to the treatment regimens and compared the efficacy between the two groups. The study showed that TACE combined with cryoablation could significantly improve the OS of HCC patients with tumors ≥10 cm compared with TACE alone. There were fewer complications. This study further optimized the above research ideas to analyze the impact of this treatment regimen on the survival of HCC patients. However, few researchers have directly compared the efficacy and safety of the two combination therapies [18]. Wei et al. selected 108 patients with advanced liver cancer and divided them into the TACE-MWA group (n = 48) and THE ACE-CRA group (n = 60), compared the overall survival (OS) and time to disease progression (TTP) of the two groups, and observed the occurrence of complications in the two groups. This study found that TESE-MWA and TESE-CRA had similar efficacy in the treatment of advanced unresectable liver cancer, but the complication rate of TESE-MWA was lower [19]. This study further explored the therapeutic effects of different therapeutic regimens for hepatocellular carcinoma in terms of tumor size and tumor type. In fact, due to the hidden development of liver cancer, early diagnosis is difficult; many patients have been found in initial progress for more than 5 cm large HCC, and its prognosis is often less than patients with small liver cancer. Its research significance is self-evident. In Niu et al.'s study, the median OS of the TESE-MWA group was 20.9 months, the median time to disease progression (TTP) was 8.8 months, and that of the TESE-CRA group was 13.0 months and 9.3 months, respectively. In our study, the median OS of the T-MWA group was 19.2 months. The median PFS was 9.3 months, while the median PFS in the T-CRA group was 18.6 months and 12.3 months, respectively. The difference in long-term efficacy between the two studies in the TACE combined with the CRA group may be attributed to the higher proportion of patients with multiple tumor lesions and PVTT in the former t-CRA group [20]. In our study, the proportion of patients with multiple tumor lesions and PVTT in the T-CRA group was 47.5% and 32.5%, respectively. Secondly, in terms of surgery-related complications and adverse events, Wei et al. believed that the t-MWA regimen had fewer complications, especially in thrombocytopenia, and this study found that the t-CRA treatment regimen could effectively relieve perioperative abdominal pain. These studies indicated that TACE combined with ablative therapy could effectively improve the therapeutic efficacy of large HCC patients, and no serious complications were observed.

It has been pointed out that cryopablative treatment for liver cancer may lead to adverse reactions of liver hemorrhage, and even lead to serious complications such as patients with uncontrolled hemorrhagic shock, but this study found that in the perioperative period in patients undergoing joint scheme, the phenomenon of the liver hemorrhage is rare and also have no observed cases of serious consequences; we think the possible reason is blood supply artery embolization with conventional tumors, effectively reducing the risk of bleeding during ablation [21]. In addition, the superliquid iodide oil used in TACE shows high density in plain CT scanning, which provides an accurate marker for CT-guided ablation and helps to accurately cover the entire tumor lesion. Thanks to the complementary advantages of the two technologies, in this study, the DCR rates of T-MWA and T-CRA groups were as high as 95.1% and 92.5%, respectively, and the ORR also reached 73.2% and 60%, Basically consistent with the results of previous studies Leuchte et al. [22], it further suggests that adjuvant TACE treatment can improve the efficacy, and the main mechanisms of action are analyzed as follows: At the same time, ablation also makes up for the shortcomings of incomplete TACE embolization, vascular recanalization, or reformation after embolization, and previous studies have shown that ablation can lead to the release of specific antigens after tumor cell rupture and also induce abscopal effects mediated by the antitumor immune response, thus further increasing the efficacy. Improve patient prognosis [23].

Clinically, the combination of TACE ablation should be individually selected according to the specific situation of the patients because the two ablation methods have their own characteristics. Microwave ablation has high frequency and strong penetration, and multineedle combined ablation has a synergistic effect and is not easily affected by the heat sink effect. Therefore, microwave ablation is heated up quickly, has a high intratumor temperature, and has a short ablation time and a large ablation range. The treatment process and therapeutic effect of cryoablation are easy to monitor, with less damage to the surrounding normal liver tissue and more safety. It can also treat tumors close to the dangerous site. In addition, cryoablation does not have the pain caused by high temperature and does not require intraoperative general anesthesia, which can reduce the risk of anesthesia [7]. Therefore, we recommend cryoablation for tumors adjacent to the gallbladder, gastrointestinal tract, diaphragm, etc. For lesions adjacent to the peritoneum, cryoablation can effectively reduce patients' pain, increase patients' compliance, and contribute to the realization of CR. However, cryotherapy will consume platelets in patients during treatment and should be avoided for patients with poor coagulation function [24].

There are some limitations to this study. First of all, this is a single-center retrospective study, which inevitably has some selective bias, leading to bias in the study results. On the basis of scientific evaluation by the team, the choice of our treatment plan fully respects the wishes of patients and their families and is greatly subjective due to the economic factors of patients, so the randomness is poor. Therefore, the patients in our experimental group may not fully represent the whole large HCC population. In addition, we failed to effectively record the complications and adverse reactions after TACE, failed to distinguish the complications and adverse reactions caused by TACE and ablation, and failed to form independent test samples. Finally, our sample size was small and the follow-up time was limited, which reduced our statistical power. In addition, small sample size and incomplete observation indicators may affect the bias of the research data and the overall reference value. In the follow-up research, the sample size should be further expanded to conduct in-depth research with large samples and multiple centers.

5. Conclusion

Both TACE combined with MWA and TACE combined with CRA can achieve considerable curative effect in the treatment of large liver cancer. TACE-CRA is more effective, and TACE-CRA can effectively relieve abdominal pain symptoms and reduce the risk of gastrointestinal reactions.