Microwave Ablation Versus Surgical Resection for Small (≤3 cm) Hepatocellular Carcinoma in Older Patients: A Propensity Score Matching Analysis

Abstract

Objective

To compare the efficacy of microwave ablation (MWA) and surgical resection (SR) for small (≤3 cm) hepatocellular carcinoma (HCC) in older patients.

Materials and Methods

This retrospective study initially enrolled 319 patients who were aged ≥65 years, had a single HCC ≤3 cm, and had Child-Pugh class A or B. Of these, 108 received MWA and 211 received SR. Overall survival (OS), disease-free survival (DFS), local tumor progression (LTP), complications, and postoperative hospital stay were compared between the groups. Hazard ratios (HRs) were estimated using the SR group as reference. Propensity score matching (PSM) was used to minimize confounding biases.

Results

After PSM, 80 patients each were included in the MWA and SR groups. There were no statistically significant differences in the 1-, 3-, and 5-year OS rates (MWA: 96.2%, 80.3%, and 55.4%, respectively; SR: 91.3%, 81.4%, and 64.8%, respectively; HR = 1.06; 95% confidence interval [CI], 0.61–1.85; P = 0.839) and DFS rates (MWA: 72.4%, 43.2%, and 26.4%, respectively; SR: 78.8%, 51.2%, and 38.0%, respectively; HR = 1.27; 95% CI, 0.84–1.90; P = 0.247) between the MWA and SR groups. MWA was associated with a higher LTP rate (HR = 2.96; 95% CI, 1.21–7.28; P = 0.028). Additionally, older patients in the MWA group had fewer complications (52.5% vs. 97.5%, P < 0.001) and shorter postoperative hospital stay (3 days vs. 6 days, P < 0.001) than those in the SR group.

Conclusion

In older patients with a single HCC ≤3 cm, MWA was superior to SR in terms of complications and postoperative hospital stay, and there was no significant difference in the 5-year OS and DFS outcomes. Therefore, MWA may be an alternative curative treatment for such patients.

INTRODUCTION

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and the third leading cause of cancer-related deaths worldwide [1]. With the continuous increase in life expectancy and the shift of global age structure of the population towards an aging pattern, along with the increasing incidences of HCC and Hepatitis B virus (HBV) infection among the older people, the number of older patients with HCC is anticipated to further increase [2,3,4]. Thus, the management of older patients with HCC has become a global health issue. Surgical resection (SR) is considered the first-line treatment for HCC ≤3 cm, as it achieves radical tumor removal [5,6]. However, SR results in a higher rate of postoperative complications and a longer recovery time because it damages the liver parenchyma; this is undesirable in older patients with HCC, especially in those with poor hepatic functional status and other chronic diseases [3,7,8]. Less trauma implies faster physical recovery; therefore, minimally invasive procedures may be more acceptable in this population.

Microwave ablation (MWA) has developed rapidly in recent years and has been widely adopted as a potent tool for the treatment of HCC. Our latest research has confirmed that the overall survival (OS) following MWA is comparable to that after SR, even when the HCC is in proximity to the liver capsule or is comorbid with clinically significant portal hypertension [9,10]. The American Association for the Study of Liver Diseases (AASLD) has recommended MWA as an effective treatment for patients with early HCC ≤3 cm who are ineligible for or refuse surgery [6]. Relative to SR, MWA provides comparable survival outcomes for patients with HCC up to 3 cm and is associated with shorter hospital stays and fewer complications [11,12]. Recent studies have shown that older and younger patients with HCC similarly benefit from MWA [13,14,15]. However, the comparative therapeutic outcomes of MWA and SR in older patients with small HCC remain unclear.

This study was designed to compare the efficacies of MWA and SR for small (≤3 cm) HCCs in older patients. Propensity score matching (PSM) was employed to improve the ability to compare between the groups.

MATERIALS AND METHODS

Patients

This study was approved by the Institutional Review Board of Shandong Provincial Hospital (SWYX: IRB No. 2022-079) and the requirement for informed consent from patients was waived owing to its retrospective nature. HCC was diagnosed based on the AASLD guidelines [6]. According to the World Health Organization definition and age cut-offs reported in most previous studies, older people were defined as adults aged 65 years or more [3,16,17].

A total of 4362 patients with HCC who had received MWA or SR as initial treatment from January 2012 to November 2023 at Shandong Provincial Hospital were screened for eligibility. The inclusion criteria were as follows: 1) age ≥65 years, 2) solitary HCC ≤3 cm in diameter, and 3) Child-Pugh class A or B. The exclusion criteria were as follows: 1) presence of macrovascular invasion or extrahepatic metastasis, 2) combined with other malignancies or other serious comorbidities, such as hepatic encephalopathy, upper gastrointestinal bleeding, or liver cancer rupture, and 3) incomplete clinical information and follow-up data. Finally, 319 patients were enrolled, of whom 108 were treated with MWA and 211 with SR. The detailed patient selection process is illustrated in Figure 1.

Fig. 1. Flowchart of study patient selection. HCC = hepatocellular carcinoma, MWA = microwave ablation, SR = surgical resection.

Treatments and Follow-Up

The individual treatment plans of the patients were determined by a multidisciplinary team, including oncologists, hepatobiliary surgeons, radiologists, and interventional radiologists, and were based on patient preference. The SR procedures were performed by a team of experienced hepatobiliary surgeons under general anesthesia using an open approach. Anatomic resection was the primary choice, and non-anatomic resection was used in cases where the former was not feasible. The extent of resection depended on the size and location of the tumor, as well as the liver function status of the patient. The operator ensured that at least 1 cm of the tumor margin was removed during the procedure. Routine intraoperative ultrasound was performed to assess the tumor status and resection margins. The Intermittent Pringle maneuver was routinely applied to control intraoperative bleeding. The status of the tumor margins was independently confirmed by two pathologists based on the surgical specimens.

MWA was performed by an experienced team of interventional radiologists. A microwave ablator (MTC-3C, Vison Medical Devices R&D Center, Nanjing, China) with a water-cooled microwave antenna was used during the procedure, with an output power of 40–80 W at 2450 ± 50 MHz for 3–10 minutes at each site. Intravenous midazolam and fentanyl were used for conscious sedation, along with 1% lidocaine for local anesthesia. A microwave antenna was inserted percutaneously into the tumor at a predetermined location under real-time ultrasound or CT guidance. Adjacent vulnerable organs were separated using artificial ascites to avoid ablation-induced thermal damage. Tumors <2 cm in maximum diameter were ablated using a single microwave antenna, while tumors >2 cm were ablated using two microwave antennas simultaneously. The ablation zone was required to cover the entire tumor and exceed 1 cm around the HCC. Antenna track ablation was routinely performed during needle removal to reduce the risk of bleeding and tumor implantation metastasis. The completeness of ablation was assessed using contrast-enhanced ultrasound or CT/MRI within 1–3 days after MWA, and supplemental MWA was performed as soon as possible if imaging revealed a residual tumor.

Patients underwent follow-up evaluations within 1–3 months of treatment, including liver function tests, alpha-fetoprotein levels, and contrast-enhanced ultrasound or CT/MR imaging at 3-month intervals for the first year and every 3–6 months thereafter. Disease recurrence was defined as the detection of newly developed lesions on diagnostic imaging. Upon detection of tumor recurrence, a thorough evaluation of the patient’s liver function and tumor burden was required at the first opportunity to determine a new treatment plan.

Therapeutic Outcomes

OS, disease-free survival (DFS), and local tumor progression (LTP) were compared between the two groups before and after PSM. OS was defined as the period of time from the first treatment for HCC to death or the last follow-up. DFS was defined as the interval from initial treatment to recurrence, death, or last follow-up, whichever occurred first. New lesions appearing within or around the ablation area and at the margins of the resection were considered LTP.

Additionally, intraoperative blood loss, complication rates, and postoperative hospital stay were compared between the two groups. During MWA, CT or ultrasound imaging was used to calculate the amount of blood loss by measuring the three-dimensional diameter of the subcapsular hepatic hematoma. The grading of complication severity was based on the Clavien-Dindo classification, with major complications including grade III and above [18,19].

Statistical Analysis

Statistical analyses were conducted using SPSS version 27.0 (IBM Corp., Armonk, NY, USA) and GraphPad Prism version 9.0 (GraphPad Software Inc., Boston, MA, USA). To minimize the selection bias, a 1:1 PSM with a 0.05 caliper was applied, incorporating variables with P ≤ 0.2 in the baseline comparisons. Standardized mean difference (SMD) was used to assess the balance of covariates between groups, with SMD <0.1 being considered sufficiently balanced. Categorical variables were compared using Pearson’s chi-square test or Fisher’s exact test, whereas continuous variables were compared using independent samples t-tests or the Mann–Whitney U test. OS, DFS, and LTP were analyzed using the Kaplan–Meier method; the hazard ratios (HRs) with the SR group as the reference and its 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression. All tests were two-tailed, and results with P < 0.05 were considered statistically significant.

RESULTS

Baseline Characteristics

In total, 319 older patients with small HCC were enrolled in the study and assigned to one of two groups based the initial therapeutic modality used; 108 and 211 patients received MWA and SR, respectively (Table 1). Before PSM, the MWA group had more patients with portal hypertension (37.0% vs. 19.9%, P < 0.001), lower model for end-stage liver disease (MELD) scores (7.5 vs. 7.9, P = 0.016), lower platelet (PLT) counts (133.5 x 10⁹/L vs. 149.0 x 10⁹/L, P = 0.003), and smaller tumor size (1.8 cm vs. 2.4 cm, P < 0.001) than the SR group.

Table 1. Baseline characteristics before and after PSM.

Variables		Before PSM				After PSM
		MWA group (n = 108)	SR group (n = 211)	P	SMD	MWA group (n = 80)	SR group (n = 80)	P	SMD
Age, yrs		69 (66–72)	69 (67–72)	0.779	0.007	69 (66–73)	68 (67–71)	0.708	0.068
Sex, male		73 (67.6)	158 (74.9)	0.168	0.168	54 (67.5)	52 (65.0)	0.738	0.052
Etiology				0.251	0.140			0.720	0.057
	HBV	76 (70.4)	161 (76.3)			58 (72.5)	60 (75.0)
	Others	32 (29.6)	50 (23.7)			22 (27.5)	20 (25.0)
Liver cirrhosis		85 (78.7)	181 (85.8)	0.108	0.203	66 (82.5)	67 (83.7)	0.833	0.033
Portal hypertension		40 (37.0)	42 (19.9)	<0.001	0.429	26 (32.5)	24 (30.0)	0.733	0.054
Child–Pugh class B		16 (14.8)	18 (8.5)	0.085	0.225	11 (13.7)	10 (12.5)	0.815	0.038
ALBI grade 2/3		55 (50.9)	100 (47.4)	0.550	0.071	37 (46.3)	34 (42.5)	0.634	0.076
MELD score		7.5 (5.0–8.8)	7.9 (7.0–9.1)	0.016	0.538	7.9 (6.8–9.2)	7.8 (6.8–8.7)	0.714	0.002
PLT, x109/L		133.5 (87.0–160.8)	149.0 (116.5–193.0)	0.003	0.352	134.0 (82.8–163.3)	130.5 (97.5–168.3)	0.871	0.031
AFP > 200 ng/mL		22 (20.4)	40 (19.0)	0.763	0.036	15 (18.8)	13 (16.3)	0.677	0.068
AST, U/L		30.0 (22.8–45.0)	29.0 (22.0–40.5)	0.369	0.092	30.5 (22.8–42.5)	29.5 (22.0–42.0)	0.400	0.081
ALT, U/L		26.5 (17.0–37.3)	25.0 (16.5–36.0)	0.644	0.050	26.0 (16.0–38.3)	24.0 (16.0–36.0)	0.734	0.014
TBIL, µmol/L		18.7 (13.5–23.2)	16.6 (12.9–21.4)	0.098	0.053	19.3 (14.7–23.5)	17.2 (12.9–22.3)	0.120	0.039
ALB, g/L		40.1 (36.1–42.8)	40.0 (37.6–42.9)	0.825	0.088	41.1 (36.7–43.3)	40.7 (37.8–43.8)	0.993	0.092
INR		1.1 (1.0–1.2)	1.1 (1.0–1.2)	0.639	0.021	1.1 (1.0–1.2)	1.1 (1.0–1.2)	0.753	0.098
Tumor size, cm		1.8 (1.4–2.1)	2.4 (2.0–2.8)	<0.001	0.539	1.9 (1.7–2.2)	2.0 (1.7–2.4)	0.529	0.034
Tumor location
	I, II, III, IV	27 (25.0)	58 (27.5)	0.634	0.056	21 (26.3)	20 (25.0)	0.856	0.029
	V	15 (13.9)	38 (18.0)	0.349	0.107	11 (13.8)	13 (16.3)	0.658	0.068
	VI	34 (31.5)	53 (25.1)	0.227	0.147	23 (28.8)	22 (27.5)	0.860	0.028
	VII	13 (12.0)	30 (14.2)	0.589	0.062	10 (12.5)	11 (13.8)	0.815	0.036
	VIII	19 (17.6)	32 (15.2)	0.576	0.068	15 (18.8)	14 (17.5)	0.837	0.032
	Subcapsular	29 (26.9)	77 (36.5)	0.084	0.200	24 (30.0)	22 (27.5)	0.727	0.056
	Subphrenic	13 (12.0)	30 (14.2)	0.589	0.062	8 (10.0)	9 (11.3)	0.798	0.041
	Perivascular	9 (8.3)	25 (11.9)	0.336	0.109	8 (10.0)	10 (12.5)	0.617	0.076
Imaging features predictive of MVI
	Non-smooth tumor margins	43 (39.8)	94 (44.6)	0.419	0.095	34 (42.5)	34 (42.5)	1.000	0
	Peritumoral enhancement	25 (23.2)	47 (22.3)	0.860	0.021	20 (25.0)	19 (23.8)	0.854	0.029

Data are presented as n (%) or median (interquartile range).

PSM = propensity score matching, MWA = microwave ablation, SR = surgical resection, SMD = standardized mean difference, HBV = hepatitis B virus, ALBI = albumin-bilirubin, MELD = model for end-stage liver disease, PLT = platelet count, AFP = alpha-fetoprotein, AST = aspartate aminotransferase, ALT = alanine aminotransferase, TBIL = total bilirubin, ALB = albumin, INR = international normalized ratio, MVI = microvascular invasion

Eighty patients from each group underwent PSM (Table 1). The PSM-matched patients were balanced in terms of all the baseline characteristics (SMD < 0.1), including previously identified significantly different variables, such as portal hypertension, MELD scores, PLT counts, and tumor size. In addition, the location characteristics of the tumor in proximity to large vessels or the liver capsule and the imaging features predictive of microvascular invasion (MVI) were balanced.

Overall Survival

The median follow-up time for these 319 patients was 46 months (range: 1–119 months). Before PSM, 36/108 patients (33.3%) in the MWA group and 56/211 patients (26.5%) in the SR group died during the follow-up period. The median OS were 71 and 70 months in the MWA and SR groups, respectively. The 1-, 3-, and 5-year OS rates were 96.2%, 82.3%, and 61.9%, respectively, in the MWA group and 91.5%, 79.1%, and 65.9%, respectively, in the SR group (HR, 1.02; 95% CI, 0.67–1.54; P = 0.942) (Fig. 2A).

Fig. 2. Kaplan–Meier curves showing the OS of older patients with HCC treated with MWA and SR before (A) and after (B) PSM. There was no significant difference in the OS rates between the MWA and SR groups both before and after PSM. OS = overall survival, HCC = hepatocellular carcinoma, MWA = microwave ablation, SR = surgical resection, PSM = propensity score matching, HR = hazard ratio, CI = confidence interval.

After PSM, 28/80 patients (35.0%) in the MWA group and 22/80 patients (27.5%) in the SR group died during the follow-up period. The median OS were 68 and 67 months in the MWA and SR groups, respectively. The 1-, 3-, and 5-year OS rates were 96.2%, 80.3%, and 55.4%, respectively, in the MWA group and 91.3%, 81.4%, and 64.8%, respectively, in the SR group (HR, 1.06; 95% CI, 0.61–1.85; P = 0.839) (Fig. 2B).

Disease-Free Survival

In total, 197 patients experienced relapse or died during the follow-up period. MVI was pathologically confirmed in 89 patients (42.2%) in the SR group. Before PSM, 57/108 patients (52.8%) in the MWA group and 93/211 patients (44.1%) in the SR group experienced recurrence. The median DFS in the MWA and SR groups were 33 and 37 months, respectively. Kaplan–Meier analysis showed that the 1-, 3-, and 5-year DFS rates were 72.2%, 46.5%, and 32.2%, respectively, in the MWA group and 80.1%, 51.1%, and 34.8%, respectively, in the SR group, with no significant difference between the groups (HR, 1.11; 95% CI, 0.82–1.50; P = 0.482) (Fig. 3A).

Fig. 3. Kaplan–Meier curves showing the DFS rates of older patients with HCC treated with MWA and SR before (A) and after (B) PSM. There was no significant difference in the DFS rates between the MWA and SR groups both before and after PSM. DFS = disease-free survival, HCC = hepatocellular carcinoma, MWA = microwave ablation, SR = surgical resection, PSM = propensity score matching, HR = hazard ratio, CI = confidence interval.

After PSM, 44/80 patients (55.0%) in the MWA group and 30/80 patients (37.5%) in the SR group experienced recurrence. The median DFS in the MWA and SR groups were 24 and 39 months, respectively. The 1-, 3-, and 5-year DFS rates were 72.4%, 43.2%, and 26.4%, respectively, in MWA group and 78.8%, 51.2%, and 38.0%, respectively, in SR groups, with no significant difference between groups (HR, 1.27; 95% CI, 0.84–1.90; P = 0.247) (Fig. 3B).

Local Tumor Progression

Before PSM, LTP was detected in 18/108 patients (16.7%) in the MWA group and 13/211 patients (6.2%) in the SR group. The cumulative 1-, 3- and 5-year LTP rates were 8.4%, 17.6%, and 19.9%, respectively, in the MWA group and 1.5%, 4.7%, and 10.7%, respectively, in the SR group (HR, 2.76; 95% CI, 1.31–5.82; P = 0.004) (Fig. 4A). After PSM, LTP was detected in 14/80 patients (17.5%) in the MWA group and 5/80 patients (6.2%) in the SR group. The cumulative 1-, 3- and 5-year LTP rates were 7.6%, 18.6%, and 22.2%, respectively, in the MWA group and 1.3%, 4.5%, and 10.9%, respectively, in the SR group (HR, 2.96; 95% CI, 1.21–7.28; P = 0.028) (Fig. 4B).

Fig. 4. Kaplan–Meier curves showing the cumulative incidence of LTP in older patients with HCC treated with MWA and SR before (A) and after (B) PSM. Notably, significant differences in LTP rates were consistently observed between the MWA and SR groups both before and after PSM. LTP = local tumor progression, HCC = hepatocellular carcinoma, MWA = microwave ablation, SR = surgical resection, PSM = propensity score matching, HR = hazard ratio, CI = confidence interval.

Complication Rate and Postoperative Hospital Stay

After PSM, the MWA group showed significantly lesser intraoperative blood loss than the SR group (15 vs. 200 mL, P < 0.001). While the SR group demonstrated a significantly higher rate of postoperative complications than the MWA group (97.5% vs. 52.5%, P < 0.001), the rates of major complications (Clavien-Dindo classification grade ≥ III) were not significantly different (8.8% vs. 15.0%, P = 0.222). Patients experienced considerably lower pain after MWA than after SR, according to the numerical rating scale pain score (0 vs. 2, P < 0.001). Moreover, fewer patients in the MWA group experienced postoperative fever (7.5% vs. 33.8%, P < 0.001), hypoproteinemia (3.8% vs. 21.3%, P < 0.001), or received blood transfusions (2.5% vs. 18.8%, P < 0.001).

In addition, the MWA group had significantly shorter operative times (30.0 min vs. 163.0 min, P < 0.001) and postoperative hospital stays (3 days vs. 6 days, P < 0.001) than the SR group after PSM. In terms of mortality within 90 days, only one patient developed infectious shock after SR and eventually died of multiple organ failure. Detailed comparative analyses of the complications and postoperative hospital stay between the MWA and SR groups are presented in Table 2.

Table 2. Complications and postoperative hospital stay.

Variables		Before PSM			After PSM
		MWA group (n = 108)	SR group (n = 211)	P	MWA group (n = 80)	SR group (n = 80)	P
Postoperative complications		58 (53.7)	207 (98.1)	<0.001	42 (52.5)	78 (97.5)	<0.001
Clavien-Dindo classification
	I–II	55 (50.9)	194 (91.9)	<0.001	40 (50.0)	71 (88.8)	<0.001
	III–VI	9 (8.3)	31 (14.7)	0.105	7 (8.8)	12 (15.0)	0.222
NRS pain score		0 (0–1)	2 (2–3)	<0.001	0 (0–1)	2 (2–3)	<0.001
Fever		11 (10.2)	72 (34.1)	<0.001	6 (7.5)	27 (33.8)	<0.001
Hypoproteinemia		5 (4.6)	44 (20.9)	<0.001	3 (3.8)	17 (21.3)	<0.001
Blood transfusion		4 (3.7)	33 (15.6)	0.002	2 (2.5)	15 (18.8)	<0.001
Infection		3 (2.8)	19 (9.0)	0.038	2 (2.5)	4 (5.0)	0.683
Hydrothorax		7 (6.5)	16 (7.6)	0.719	5 (6.3)	6 (7.5)	0.755
Severe ascites		1 (0.9)	7 (3.3)	0.361	0 (0)	3 (3.8)	0.244
Hepatic failure		0 (0)	1 (0.5)	1.000	0 (0)	0 (0)	1.000
90-day mortality		0 (0)	1 (0.5)	1.000	0 (0)	1 (1.3)	1.000
Intraoperative blood loss, mL		15 (10–20)	200 (150–300)	<0.001	15 (10–20)	200 (150–350)	<0.001
Operative time, min		30.0 (24.8–36.0)	156.0 (126.0–214.5)	<0.001	30.0 (24.0–36.0)	163.0 (119.8–229.3)	<0.001
Postoperative hospital stay, days		3 (2–5)	6 (5–8)	<0.001	3 (2–5)	6 (4–9)	<0.001

Data are presented as n (%) or median (interquartile range).

PSM = propensity score matching, MWA = microwave ablation, SR = surgical resection, NRS = numerical rating scale

DISCUSSION

Considering the continuously increasing number of older patients with HCC, strengthening the clinical management of this group has become urgent. The precise choice of treatment is closely related to the quality of survival of older patients. This study demonstrated no difference in the 5-year OS and DFS rates of the MWA and SR groups in the treatment of older patients with small (≤3 cm) HCC. Compared with the SR group, the MWA group had fewer complications and shorter postoperative hospital stay.

Several previous studies have compared MWA and surgery for HCC in patients of all ages. Ryu et al. [20] enrolled 551 patients with single HCC ≤5 cm, with median ages of 68 years (range: 42–85 years) and 71 years (range: 38–87 years) in the SR and MWA groups, respectively. The authors concluded that there were no statistically significant differences between the two treatments in terms of OS and recurrence-free survival rates. Wang et al. [21] retrospectively analyzed 1289 patients with HCC with a median age of 57 years (range: 20–88 years) and demonstrated that MWA achieved survival outcomes comparable to those following laparoscopic hepatectomy for a single 3–5 cm HCC. However, the survival outcomes of MWA in older patients with small (≤3 cm) HCCs remains a problem.

A previous study has compared the survival outcomes between SR and MWA in older patients with HCC using Japanese data from 2001 to 2007 [22]. Since 2013, the rapid development of the ablation techniques, including artificial fluid infusion, three-dimensional ablation plans, and multi-model image fusion navigation, has promoted complete necrosis of HCC lesions and improved the survival outcomes in patients [23,24]. In our study, we collected data from 319 older patients who underwent advanced MWA techniques between 2012 and 2023. These data could provide updated and valuable evidence for older patients with HCC treated with MWA. Wang et al. [25] assessed the treatment efficacy of MWA and laparoscopic hepatectomy for HCC (3–5 cm) in older patients, but patients with tumors less than 3 cm in size were excluded. Our study enrolled older patients with small (≤3 cm) HCC and found that MWA achieved similar OS and DFS rates and fewer complications compared with SR. This result indicates that MWA might be an alternative curative option for older patients with small HCC, strengthening the evidence base for the application of MWA in older patients. The median follow-up period in this study was 46 months. In the future, continuous follow-ups will be conducted on these patients to obtain long-term outcomes over a 10-year period to further validate the findings of this study.

In terms of LTP, several previous meta-analyses have indicated that the risk of local progression in patients with HCC was significantly higher after treatment with MWA than with SR [26,27]. In the current study, LTP rates were significantly higher for MWA than for SR. After PSM, LTP was detected in 5/80 patients (6.2%) in the SR group, while the 5-year LTP rate in this group was 10.9%. The relatively high LTP rate may be attributed to the fact that our center, as a tertiary hospital, admits patients with more severe disease and higher MVI rates (42.2%) than primary care settings. Our previous related studies in the same hospital yielded similar 5-year LTP rates of 10.6% and 8.2% after SR [9,10]. It is well-established that MWA is incapable of achieving as sufficient a safe margin as the R0 resection in SR, which might account for over 50% of LTP occurrences being localized at the ablation margin [26,28].

Older patients tend to have poorer health because of physical decline and more comorbidities, which leads to lower tolerance to SR and higher therapeutic risks in this population [3,25]. For instance, the majority of older patients with HCC are at an increased risk of bleeding and hepatic decompensation after SR because of comorbid cirrhosis [3,29]. Prolonged general anesthesia during SR increases the likelihood of various anesthesia-related risks, including postoperative cognitive dysfunction, delirium, and potentially mortality, particularly in older patients [30,31]. The minimally invasive nature of MWA minimizes damage to healthy tissues and maintains the integrity of liver function [9]. The present study revealed that MWA was superior to SR in terms of intraoperative bleeding and postoperative complications, such as pain, fever, hypoproteinemia, and blood transfusion. Moreover, MWA was associated with a significantly shorter operative time and postoperative hospital stay than SR. These findings were consistent with those of previous studies [11,26,32]. Therefore, MWA offers more advantages than SR in terms of complications and postoperative hospital stay and is a safer treatment option for older patients with HCC.

Our study has some limitations. First, despite the use of scientific PSM methods to control for confounding variables, some inherent selectivity biases could not be completely removed because of the retrospective nature of the study. Second, the success of the MWA technique depends on the technical level of the operator at our center because of the single-center nature of this study. Whether the utility of these findings can be extended to other centers requires further validation. Third, the etiology of the patients in this study was predominantly HBV infection, and the results need to be verified in populations with other etiologies.

In conclusion, MWA was superior to SR in the treatment of older patients with a single HCC ≤3 cm, in terms of complications and postoperative hospital stay; there was no significant difference in the 5-year OS and DFS outcomes. Therefore, MWA may be an alternative curative treatment for such patients.

Availability of Data and Material

The datasets generated or analyzed during the study are available from the corresponding author on reasonable request.