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

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.