Characteristics of Cases and Follow-up Results
Among the included 101 cases, there were 64 males and 37 females. The age ranged from 28 to 88 years, with a mean age of 61.3 ± 11.87 years. Among them were 47 cases of hepatitis B, 8 cases of hepatitis C, 46 cases of non-hepatitis, and 57 cases of liver cirrhosis. In the preoperative liver function assessment, 82 cases were classified as Child-Pugh A grade, while 19 were classified as B. There were 89 cases of single lesions, 12 cases of multiple lesions, 78 cases of lesions smaller than 3 centimeters, 18 cases of lesions ranging from 3 to 5 centimeters, and 5 cases of lesions larger than 5 centimeters. A total of 56 cases of primary malignant tumors and 45 cases of secondary malignant tumors were identified. Postoperative follow-up was carried out until October 2018, with a follow-up period ranging from 6 to 44 months. The average follow-up time was 26.45 ± 10.53 months. As of October 2018, there were 22 cases of recurrence, 79 cases of no recurrence, 97 cases of survival, and 4 cases of death. The disease-free survival rates at 1, 2, and 3 years after surgery were 80.2%, 72.3%, and 70.3%, respectively. Similarly, the overall survival rates at 1, 2, and 3 years after surgery were 99%, 97%, and 96%, respectively.
Results of Single-factor Analysis
During the follow-up observation of 101 patients, it was found that 22 patients experienced recurrence after undergoing microwave ablation treatment, while the remaining 79 patients were recurrence-free. In the recurrent cases, there were 15 males and 7 females. Out of the total, there were 12 cases with cirrhosis, 10 cases with a history of hepatitis, 10 cases with Grade A liver function, 12 cases with Grade B liver function, 15 cases with a single lesion, 7 cases with multiple lesions, and 21 cases with a diameter of ≤ 5 centimeters. Additionally, there were 11 cases of primary liver tumors and 11 cases of secondary liver tumors. A single-factor analysis was conducted on several variables. The results demonstrated a significant correlation between recurrence and the number of lesions in the Child-Pugh B stage (P < 0.05). However, there was no correlation between recurrence and gender, age, tumor type, history of hepatitis, or cirrhosis (P > 0.05). Please refer to Table 1 for specific results.
Table 1
Univariate analysis of factors related to recurrence after percutaneous microwave ablation treatment for hepatic malignant tumors
Factor | Number of Cases | Recurrence | No Recurrence | P-value |
Gender | male | 64 | 15 | 49 | 0.596 |
female | 37 | 7 | 30 | |
Age | > 60 | 59 | 15 | 44 | 0.293 |
≤ 60 | 42 | 7 | 35 | |
cirrhosis | Yes | 57 | 12 | 45 | 0.84 |
No | 44 | 10 | 34 | |
History of hepatitis | Yes | 55 | 10 | 45 | 0.338 |
No | 46 | 12 | 34 | |
Child Pugh grading | A | 82 | 10 | 72 | < 0.001 |
B | 19 | 12 | 7 | |
Number of lesions | single | 89 | 15 | 74 | 0.001 |
Multiple | 12 | 7 | 5 | |
Lesion size | < 3cm | 79 | 16 | 63 | 0.407 |
3-5cm | 17 | 5 | 12 | 0.678 |
> 5cm | 5 | 1 | 4 | 0.146 |
Tumor type | Primary | 56 | 11 | 45 | 0.561 |
secondary | 45 | 11 | 34 | |
The Impact of Melting Parameters on the Range
We screened the characteristics of 55 cases from the data, which included intraoperative parameters and complete postoperative imaging data at 1 month. It is important to note that all cases in the study had a single lesion. The majority of lesions have a maximum diameter of ≤ 3cm (which accounts for 96.3% of cases), whereas a minority of cases have a maximum diameter of ≤ 5cm. 3. Use the same model as the ablation needle. 4. All are single-electrode, single-point ablations. The analysis of ablation power and time reveals that, within a specific range, ablation's transverse and longitudinal diameters gradually increase with the increase in power and time. Statistical significance (P < 0.05) is observed when the ablation power is set at 60W for a duration of 6 minutes, as compared to 5 minutes. Similarly, when the ablation time is 6 minutes, statistical significance (P < 0.05) is observed between the ablation power of 60W and 55W or 50W. Please refer to Fig. 2.
A meta-analysis Provides Additional Confirmation of the Close Relationship Between the Number of Lesions and the Child-Pugh B Grade with the Recurrence of Liver Malignant Tumors in Patients who Undergo Percutaneous Microwave Ablation
We conducted a thorough literature search across multiple databases, such as PubMed, EMBASE, Cochrane Library, and CNKI. Keywords include "microwave ablation", "malignant liver tumor", and "recurrence". A total of 1280 articles were retrieved. Duplicates, unrecorded data, comments, expert opinions, case reports, and non-systematic reviews were excluded based on the title. Additionally, articles focusing on combination therapy and liver diseases other than the selected condition were excluded, resulting in 75 articles. Each included article underwent a meticulous screening process to eliminate those lacking statistical recurrence data or reported recurrence without conducting multiple-factor regression analysis. Eventually, 10 retrospective studies were included in the meta-analysis (Fig. 3). Relevant information about the author, publication date, study design, patient characteristics, and key findings were extracted from the article (Table 3).
Table 3
Incorporate basic characteristics of literature.
Authors | Year | Country | Child–Pugh B | Multiple nodule |
P-value | HR | 95% CI | P-value | HR | 95% CI |
Tomoki Ryu PMID: 34618325 | 2022 | Japan | 0.013 | 1.44 | 1.080–1.890 | < 0.001 | 1.51 | 1.22–1.87 |
Kanehiko Suwa PMID: 33675382 | 2021 | Japan | 0.708 | 1.09 | 0.696–1.706 | 0.051 | 1.149 | 0.999–1.321 |
Tianqiang Jin PMID: 32781862 | 2020 | China | 0.66 | 1.215 | 0.511–2.890 | < 0.004 | 2.825 | 1.401–5.695 |
Yun Xu PMID: 27649577 | 2017 | China | 0.023 | 2.657 | 1.001–7.052 | | | |
Tao Wang PMID: 27620527 | 2016 | China | | | | | 0.98 | 0.515–1.866 |
Chenwei Wang PMID:32449005 | 2020 | China | | | | 0.002 | 1.68 | 1.05–2.68 |
Zhiwei Chen CNKI | 2021 | China | 0.203 | 1.481 | 0.809–2.714 | < 0.001 | 2.547 | 1.532–4.237 |
Yuan Lv CNKI | 2020 | China | 0.36 | 2.56 | 0.350–18.970 | 0.17 | 1.55 | 0.83ཞ2.90 |
Fan Xie CNKI | 2022 | China | | | | < 0.001 | 2.998 | 1.858–4.836 |
Tomoki Ryu PMID: 31359277 | 2019 | Japan | | | | < 0.001 | 1.64 | 1.29–2.08 |
Note: HR: Hazard Ratio; CI: Confidence Interval |
Firstly, we aim to analyze the correlation between Child-Pugh B classification and recurrence rates following percutaneous microwave ablation. Upon conducting a preliminary statistical synthesis of the data from the included studies, the I2 test revealed an absence of significant heterogeneity among the groups (I2 = 0%, p = 0.64). Additionally, the funnel plot demonstrated the absence of publication bias (Fig. 4A-B). A fixed-effects model was used for analysis, yielding a pooled hazard ratio (HR) of 1.39 with a 95% confidence interval (CI) of [1.13, 1.72]. The p-value of less than 0.01 suggests a statistically significant increase in the risk of recurrence among patients with Child-Pugh B who underwent percutaneous microwave ablation therapy (Fig. 4C).
Subsequently, we examined the association between the number of lesions and recurrence following percutaneous microwave ablation. Our analysis revealed considerable heterogeneity among the studies (I² > 50%, p < 0.01) (Fig. 5A-B). Thus, we selected the random-effects model for meta-analysis to consider the possible variations among studies. Using random effects models, the analysis revealed a pooled hazard ratio (HR) of 1.69, with a 95% confidence interval (CI) of [1.33, 2.13] and a p-value of less than 0.01, indicating a statistically significant difference (Fig. 5C). These findings suggest that patients with multiple lesions have a significantly higher risk of postoperative recurrence than those with a single lesion. In particular, patients with multiple lesions have a significantly higher risk of postoperative recurrence when compared to those with a single lesion.
These findings are in line with previous outcomes reported by single-center studies. However, the larger sample size and higher statistical power of the meta-analysis enhance the stability and reliability of these findings.
In conclusion, our meta-analysis solidifies the strong association between tumor number and Child-Pugh B class and the recurrence of malignant liver tumors following percutaneous microwave ablation. This study offers precise guidance for clinical doctors, enabling them to assess postoperative recurrence risk accurately and develop tailored follow-up strategies for high-risk patients.