Intraoperative laparoscopic ultrasound-guided resection and microwave ablation for colorectal liver metastases

Table 1 Comparison of baseline characteristics between the two groups (mean ± SD)

Group	n	Gender (n)		Age (years)	Body mass index (kg/m2)	Number of liver metastases		Primary tumor location
		Male	Female			Single	Multiple	Rectal cancer	Colon cancer
Control	150	74	76	59.60 ± 2.15	19.52 ± 0.77	81	69	79	71
Observation	150	77	73	59.98 ± 2.74	19.49 ± 0.83	83	67	76	74
t/χ²		0.120		1.336	0.325	0.054		0.120
P value		0.729		0.183	0.746	0.817		0.729

Table 2 Comparison of therapeutic effects between two groups, n (%)

Group	n	Complete response	Partial response	Stable disease	Progressive disease	Overall response rate
Control	150	15 (10.00)	61 (40.67)	35 (23.33)	39 (26.00)	76 (50.67)
Observation	150	17 (11.33)	89 (59.33)	31 (20.67)	13 (8.67)	106 (70.67)
χ²						12.572
P value						0.000

Table 3 Comparison of adverse reactions between two groups, n (%)

Group	n	Hepatic dysfunction	Anemia	Gastrointestinal reactions	Neurotoxicity	Incidence (%)
Control	150	27 (18.00)	10 (6.67)	13 (8.67)	11 (7.33)	61 (40.67)
Observation	150	13 (8.67)	5 (3.33)	3 (2.00)	3 (2.00)	24 (16.00)
χ²						22.473
P value						0.000

Table 4 Comparison of Karnofsky Performance Status scores between two groups (mean ± SD)

Group	n	Karnofsky Performance Status points
		Before treatment	After treatment
Control	150	66.29 ± 6.51	77.26 ± 7.16a
Observation	150	66.87 ± 6.57	84.13 ± 8.15a
t		0.768	7.756
P value		0.443	0.000

^aP < 0.05 vs before and after treatment.

Table 5 Univariate regression analysis

Factor	n	3-year overall survival (%)	95%CI	χ²	P value
Gender				0.077	0.898
Male	151	34.45	27.31-38.92
Female	149	42.27	27.12-41.13
Age	0.327			0.742	0.393
≤ 60 years	162	39.87	29.51-41.77
> 60 years	138	31.65	24.31-37.65
American Society of Anesthesiologists grade				0.043	0.992
1	56	47.92	22.17-44.91
2	213	34.63	28.21-38.94
3	31	25.18	18.81-41.56
Intraoperative contrast-enhanced ultrasound with Sonazoid				0.798	0.000
Yes	150	54.87	19.46-41.17
No	150	33.27	28.32-37.91
Postoperative T stage				0.463	0.521
T2-T3	229	43.31	29.69-40.28
T4	71	21.24	21.36-38.77
Postoperative N stage				7.954	0.020
N0	114	54.31	33.22-47.51
N1	118	26.42	25.47-39.69
N2	68	26.38	14.78-32.91
Number of liver mets				5.269	0.033
≤ 3	182	49.12	31.92-44.93
>3	118	24.63	22.31-34.17
Tumor differentiation				6.199	0.024
Low	142	52.37	33.12-45.64
Moderate/high	158	22.65	21.42-33.57

Survival rates and confidence intervals are reported as percentages. T and N stages follow the American Joint Committee on Cancer Tumor-Node-Metastasis staging system.

Table 6 Multivariate Cox regression analysis of prognostic factors

Factor	Coding	Hazard ratio	95%CI	P value
Intraoperative contrast-enhanced ultrasound with Sonazoid application	No = 0; yes = 1	2.134	1.162-3.929	0.017
Postoperative N stage	N0 = 0; N1 = 1; N2 = 2	1.459	0.995-2.169	0.176
Number of liver metastases	≤ 3 = 0; > 3 = 1	1.480	0.913-2.524	0.251
Differentiation of primary tumor	Low = 0; moderate/high = 1	0.521	0.312-0.914	0.017

Variables were coded as 0/1 for binary categories or ordinal scales (e.g., N stage).