Efficacy of microwave ablation vs laparoscopic hepatectomy for primary small liver cancer: A comparative study

Abstract

BACKGROUND

In-depth comparative investigations in terms of clinical efficacies of liver tumor microwave ablation (MWA) and laparoscopic hepatectomy (LH), which are both important treatment modalities for liver neoplasms, have been limited in patients diagnosed with primary small liver cancer (PSLC).

AIM

To compare and analyze the clinical efficacy of liver tumor MWA and LH for PSLC.

METHODS

This study retrospectively analyzed the medical records of 123 patients with PSLC admitted to Xuzhou Central Hospital from January 2015 to November 2022 and categorized them based on treatment modalities into the LH and MWA groups. The LH group, consisting of 61 cases, received LH, and the MWA group, which included 62 cases, underwent liver tumor MWA. Basic data and various perioperative indicators were compared between the two groups, including changes in liver function indicators [alanine aminotransferase (ALT), glutamic aminotransferase (AST), and total bilirubin (TBIL)] pre- and post-treatment, and efficacy and postoperative complications were analyzed.

RESULTS

No statistically significant difference was observed between the two groups in terms of age, gender, tumor diameter, liver function Child-Pugh classification and number of tumors, body mass index, and educational status (P > 0.05). The overall effective rate was higher in the MWA group than in the LH group (98.39% vs 88.52%) (χ² = 4.918, P = 0.027). The MWA group exhibited less operation time, intraoperative bleeding, defecation time, and hospital stay than the LH group (P < 0.05). No difference was found in liver function indicators between the two groups pre-treatment (P > 0.05), and ALT, AST, and TBIL levels decreased in both groups post-treatment, with the MWA group demonstrating lower levels (P < 0.05). The MWA and LH groups exhibited postoperative complication rates of 4.84% and 19.67%, respectively, with statistically significant differences between the two groups (P = 0.012, χ² = 6.318).

CONCLUSION

MWA is more effective in treating PSLC, and it promotes faster postoperative recovery for patients, and more security improves liver function and reduces postoperative complications compared to LH.

Key Words: Microwave ablation of liver tumors; Laparoscopic hepatectomy; Primary small liver cancer; Clinical outcome

Core Tip: This study primarily aimed to comparatively analyze the clinical effectiveness of liver tumor microwave ablation (MWA) and laparoscopic hepatectomy (LH) in treating primary small liver cancer (PSLC). We conducted a comparative analysis of the two intervention methods from multiple perspectives, including various perioperative indicators, changes in liver function indicators pre- and post-treatment, curative effects, and postoperative complications. This study confirmed that MWA demonstrated better curative effects than LH in PSLC treatment, with a reduced intraoperative blood loss level, shorter surgical procedure and hospitalization durations, rapid recovery facilitation, liver function improvement, postoperative complication reduction, and a high safety level. Therefore, selecting the appropriate surgical method is the key to achieving better clinical outcomes. Our analysis provides more reliable clinical references and options for future PSLC treatment.

INTRODUCTION

Primary small liver cancer (PSLC), one of the most prevalent malignant tumors globally[1,2], is a digestive system malignancy characterized by high morbidity and mortality rates. According to statistics, over 90% of primary liver cancers were hepatocellular carcinomas[3], and the rest were cholangiocellular and mixed-type hepatocellular carcinomas. Hepatocellular carcinoma was categorized based on morphological characteristics into nodular, massive, and diffuse, and according to tumor size as microscopic (diameter ≤ 2 cm), PSLC (> 2 cm, ≤ 5 cm), large (> 5 cm, ≤ 10 cm), and giant hepatocellular carcinomas (> 10 cm). One of the small liver cancers was known as early-stage liver cancer or subclinical liver cancer, with generally no obvious clinical signs and symptoms. PSLC is generally characterized by pain in the liver area, weakness, lack of appetite, wasting, and fever[4,5]. It is potentially correlated with viral hepatitis, aflatoxin, metabolic and genetic determinants, chronic alcohol ingestion, smoking, and other relevant factors[6]. The proportion of PSLC in all liver cancers is increasing annually as awareness of risk factors for primary liver cancer and health screening increases and the detection rate of small liver cancers rises due to medicine development[7]. For the treatment of primary liver cancer, the major clinical approaches include surgical resection, ablation, liver transplantation, and drug therapy[8]. The standard treatment options for PSLC were laparoscopic surgical resection and microwave ablation (MWA) of liver tumors, which represent surgical and ablative procedures, respectively. The treatment protocol that effectively manages the disease while minimizing patient harm was individually determined, considering the specific circumstances of each patient.

The etiology and pathogenesis of PSLC are currently undetermined[9]. Academic research indicated that early detection and treatment effectively save the lives of patients with PSLC[10-12]. One study[13] revealed laparoscopic hepatectomy (LH) to be less damaging to patients’ liver function, demonstrates higher liver function reserve capacity, is less invasive, causes less intraoperative bleeding, and exhibits a lower incidence of postoperative complications than open hepatectomy. The range of inactivated tissues is expanding with the continuous improvement of ablation techniques, thereby increasing definitive treatment results[14,15]. MWA is the use of physically generated high heat to coagulate and inactivate tumor tissue in the body[16,17], prompting the body to decompose, remove, or mechanize necrotic tissue, thereby destroying the lesion for eradication. MWA is less traumatic for patients and exhibits the characteristics of simple operation, quick recovery, safety, and efficiency[18]. Furthermore, it does not require tumor removal, which indicates the presence of a variety of minimally invasive methods available and a wealth of treatment opportunities and options for patients with liver cancer[19]. Moreover, it cures patients who cannot undergo surgical treatment. MWA, LH, and other surgical modalities were gaining clinical attention as one of the important treatment methods for liver tumors. A wide range of medical practitioners acknowledged its advantages and disadvantages.

However, studies comparing MWA with LH were scarce. This study aims to investigate the clinical efficacy of MWA and LH in PSLC treatment.

MATERIALS AND METHODS

Subjects

This study retrospectively analyzes the medical records of 123 patients with PSLC admitted to Xuzhou Central Hospital from January 2015 to November 2022, categorized based on treatment modality into the LH (61 cases) and MWA groups (62 cases).

Diagnostic criteria of PSLC

Hepatocellular carcinoma confirmed by liver puncture histopathology or postoperative pathology; a single cancer foci of ≤ 3 cm in diameter; liver function Child-Pugh grades A or B[20].

Inclusion criteria

Age of > 18 years and ≤ 69 years; normal preoperative coagulation and other indicators; no extrahepatic transfer or other surgical, chemotherapeutic, or anti-tumor treatments.

Exclusion criteria

Patients with surgical contraindications; incomplete case information; cardiac, pulmonary, renal, and other vital organ insufficiency; pregnant and lactating women. The basic information of the two groups of patients.

Shedding or rejection criteria

Lost to follow-up post-discharge; automatically discharged from hospital during treatment; serious complications occurring during hospitalization (malignant arrhythmia, myocardial infarction, cardiac arrest, severe decline in muscle strength, etc.); rejecting the experimenter midway.

Criteria for loss of follow-up

Those who were actively hospitalized and refused to be followed up by telephone, or those who were unreachable during the follow-up period due to force majeure factors.

Treatment process

The LH group received LH, with the operation as follows. The patient is positioned supine. A 1-cm sub-umbilical incision was created after general anesthesia, and pneumoperitoneum was established by puncture of pneumoperitoneum needle. A 1-cm Trocar was placed via this puncture, and a laparoscopic lens was placed to explore for abdominal fluid, tumor site, size, and number, cases with a liver texture, etc., that was compatible with surgical resection. The position of the other operating trocar was identified based on the specific tumor location. The corresponding lesion area of the liver was resected with the help of an ultrasonic knife and bipolar electrocoagulation, and the resection line was identified at 2 cm from the surface of the tumor with an electric knife. The resection line was gradually cut through the liver tissue from superficial to deep and from anterior to posterior for complete resection of the liver tumor. The large vessels and corresponding bile ducts were clamped closed with a titanium clip during excision, and hemostasis was achieved through electrocoagulation. The tumor was placed in a specimen bag, and the specimen was removed from the bag after dilatation through the sub-umbilical observation hole.

The MWA group underwent liver tumor MWA as follows. The preceding steps were performed in the supine position, under general anesthesia, with pneumoperitoneum establishment and laparoscopic lens exploration, as previously in the LH group. A thermal isolation zone was established and the MWA needle was placed in the center of the tumor under the lumpectomy after accurate exploration of the tumor location under the guidance of the lumpectomy ultrasound probe. The appropriate radiofrequency voltage and time were then set and the ablation treatment was initiated after determination. The ablation protocol was selected based on the tumor size. A one- or two-point MWA was utilized for lesions of ≤ 2 cm in diameter, and a multi-point MWA was employed for lesions of > 2 cm in diameter. The ablation output was 60 W, and each ablation cycle lasted 5 minutes. The coagulation mode was changed and the needle tract was cauterized to prevent bleeding from the needle tract and to end the procedure if the ultrasound showed complete tumor ablation post-treatment. Ablation treatment was continued if tumor ablation was incomplete, and the tumor exhibited hyperechoic changes on ultrasound post-procedure, with inactivated tissue beyond the preoperative tumor margins. The procedure was completed with the choice of whether to perform a hilar block or hemihepatic blood flow block, based on tumor location in both groups.

Observation methods

Efficacy criteria[21] were identified based on the patient’s peritoneal fluid into complete remission (CR), which is the complete disappearance of ascites maintained for more than one month; partial remission (PR), with over 50% reduction in ascites; stabilizing disease (SD), with no significant change in ascites and less than 50% reduction from pre-treatment; progressive disease, with a > 25% increase in ascites from pre-treatment. Total effective rate = (CR + PR + SD) / total number of cases × 100%. The extraction time, intraoperative bleeding, defecation, and length of hospital stay were recorded for both groups. Liver function indexes pre- and post-treatment were taken from an automatic biochemical analyzer, consisting of alanine aminotransferase (ALT), glutamic aminotransferase (AST), and total bilirubin (TBIL). Postoperative complications were documented in both groups, including nausea and vomiting, lung infection, incisional infection, and abdominal bleeding. All patients were followed up from December 1, 2016, to March 30, 2023.

Statistical analysis

The measurement data (including age and tumor diameter, body mass index, operation time, intraoperative bleeding, defecation time, length of hospital stay, and liver function indicators) were presented as mean ± SD using the t-test. The count data (gender, educational status, liver function Child-Pugh classification, number of tumors, efficacy, and postoperative complications) were expressed as rates and percentages (%) using χ² tests. The test level was α = 0.05. Statistical Package for the Social Sciences version 23.0 was used for analysis.

RESULTS

Comparison of basic information between the two groups of patients

No statistically significant difference was found between the two groups in terms of age, gender, tumor diameter, liver function Child-Pugh classification and the number of tumors, body mass index, and educational status (P > 0.05) (Table 1).

Table 1 Comparison of basic information between the two groups of patients.

Group	LH group (n = 61)	MWA group (n = 62)	t/χ2	P value
Age (years)	65.27 ± 16.08	66.18 ± 16.24	0.312	0.755
Gender (M/F)	34/27	33/29	0.078	0.780
Tumour diameter (cm)	4.53 ± 1.46	4.48 ± 1.43	0.192	0.848
Liver function Child-Pugh classification (A/B)	42/19	44/18	0.065	0.798
Number of tumours (single/multiple)	47/14	46/16	0.136	0.712
Body mass index (kg/m2)	23.16 ± 4.75	23.23 ± 4.84	0.081	0.936
Education status (junior high school and below/high school and above)	39/22	37/25	0.236	0.627

LH: Laparoscopic hepatectomy; MWA: Microwave ablation.

Comparison of the efficacy of the two groups of patients

The total effective rate after treatment was 98.39% in the MWA group, which was significantly higher than in the LH group at 88.52%, with a statistically significant difference (P < 0.05) (Table 2).

Table 2 Comparison of the efficacy of the two groups of patients, n (%).

Group	Number of examples	CR	PR	SD	PD	Total efficiency
LH group	61	24 (39.34)	17 (27.87)	13 (21.31)	7 (11.48)	54 (88.52)
MWA group	62	39 (62.90)	16 (25.81)	6 (9.68)	1 (1.61)	61 (98.39)
χ2						4.918
P value						0.027

CR: Complete remission; PR: Partial remission; SD: Stabilizing disease; PD: Progressive disease; LH: Laparoscopic hepatectomy; MWA: Microwave ablation.

Comparison of perioperative indicators between the two groups of patients

The operative time, intraoperative bleeding, defecation time, and hospital stay were less in the MWA group than in the LH group (P < 0.05) (Figure 1).

Figure 1 Comparison of perioperative indicators between the two groups of patients. Indicates comparison with laparoscopic hepatectomy group. A: The duration of surgery; B: The amount of intraoperative bleeding; C: The amount of intraoperative fluids; D: The length of hospital stay. ^aP < 0.05. LH: Laparoscopic hepatectomy; MWA: Microwave ablation.

Comparison of liver function indicators pre- and post-treatment between the two groups

No difference was observed in the comparison of liver function indexes between the two groups pre-treatment (P > 0.05), and ALT, AST, and TBIL levels decreased in both groups post-treatment, which were lower in the MWA group than in the LH group (P < 0.05) (Figure 2).

Figure 2 Comparison of liver function indicators before and after treatment between the two groups. A: Alanine aminotransferase levels; B: Glutamic aminotransferase levels; C: Total bilirubin levels. ^aP < 0.05 vs the same group before treatment; ^bP < 0.05 vs the laparoscopic hepatectomy group after treatment. ALT: Alanine aminotransferase; AST: Glutamic aminotransferase; LH: Laparoscopic hepatectomy; MWA: Microwave ablation.

Comparison of postoperative complications between the two groups

The incidence of postoperative complications in the MWA group compared to the LH group (4.84% vs 19.67%) was statistically significant (P = 0.012, χ² = 6.318), tolerable, and promptly managed without affecting the normal treatment course and symptom relief (Table 3).

Table 3 Comparison of post-operative complications between the two groups of patients, n (%).

Group	Number of examples	Post-operative complications				Total incidence
		Nausea and vomiting	Lung infections	Infection of the incision	Abdominal bleeding
LH group	61	6 (9.84)	3 (4.92)	2 (3.28)	1 (1.64)	12 (19.67)
MWA group	62	2 (3.23)	1 (1.61)	0 (0.00)	0 (0.00)	3 (4.84)
χ2						6.318
P value						0.012

LH: Laparoscopic hepatectomy; MWA: Microwave ablation.

DISCUSSION

Research reveals that[22] laparoscopic MWA combined with hepatic artery chemoembolization is a safe and effective treatment option for early-stage hepatocellular carcinoma, with good recent results, prolonged survival, and low incidence of serious adverse events. This study revealed that MWA demonstrated a higher overall efficiency than LH (98.39% vs 88.52%), indicating that MWA is more effective than laparoscopic liver resection for patients with PSLC. This may be attributed to the application of an ablation needle in the MWA procedure. The ablation needle is accurately inserted into the tumor through the liver tissue under ultrasonography guidance. Subsequently, the electrode needle of the ablation device is used to generate heat within the tumor tissue utilizing high-frequency alternating current, thereby achieving the ablation effect. Tumor tissues demonstrate relatively poor heat tolerance. Coagulative inactivation is induced within the tumor tissue and the adjacent parenchymal tissue once the local temperature exceeds 50°C. Irreversible impairment of tissue cells occurs when the temperature surpasses 60°C. Moreover, the increased temperature generated by the tissue can disrupt the blood vessels that supply the tumor and the surrounding tissues. Tumor tissue necrosis becomes more comprehensive as a consequence of nutrient deprivation, which consequently diminishes the probability of intrahepatic metastasis of the tumor[23,24]. Operative time, intraoperative bleeding, defecation, and hospital stay were less in the MWA group than in the LH group, indicating that MWA promotes early recovery and is more minimally invasive for patients with small liver cancers. Liver function indicators reflect liver damage in a timelier manner. Notably, ALT, AST, and TBIL hold considerable significance. High ALT, AST, and TBIL levels are closely associated with liver damage in the body. Effective treatment interventions decrease the levels of abnormally increased liver function indices[25]. ALT, AST, and TBIL levels were lower in the treated group than in the LH group post-treatment because MWA causes coagulation and necrosis of the tumor and local liver tissue, resulting in transient impairment of liver function, decrease in ALT, AST, and TBIL levels post-treatment, and a gradual return to normal liver function due to complete absorption of necrotic tissue[26]. MWA is more convenient, less damaging to liver function, and can be repeated multiple times for single hepatocellular carcinoma of ≤ 5 cm in diameter[27]. The incidences of postoperative complications were 4.84% and 19.67% in the MWA and LH groups, respectively, with a statistically significant difference between the two groups. This indicates that MWA is a physical thermal ablation technique, with the thermal effect inducing tumor necrosis, thereby causing the death of tumor cells for therapeutic purposes. It exhibits a quick recovery, is less invasive, and demonstrates a high safety profile.

CONCLUSION

In conclusion, compared with LH, MWA of PSLC is more effective, with low intraoperative bleeding, shorter operation and hospital stay, rapid recovery, improved liver function, reduced postoperative complications, and high safety; thus, selecting the appropriate procedure is the key to achieving better clinical results.