[Evaluation of long-term therapeutic effects of ultrasound-guided percutaneous microwave ablation of liver metastases].

TLDR: There is a significantly higher probability of long-term survival for patients with well-differentiated tumors 3.0 cm or less in diameter and without recurrence or new metastasis after percutaneous microwave ablation.

Abstract: OBJECTIVE: To explore therapeutic results of local microwave ablation for hepatic metastasis and the factors influencing the survival after percutaneous microwave ablation therapy. METHODS: From July 1995 to June 2005 128 patients with 282 hepatic metastases nodules with the primary diseases of upper gastrointestinal tumor (n = 26), colorectal tumor (n = 44), breast carcinoma (n = 19), pulmonary carcinoma (n = 15), and malignant tumor in other part of the body (n = 24), underwent percutaneous microwave ablation therapy and were followed up for 29.7 +/- 19.9 months (1 - 103 months). The largest diameter of the metastatic nodules was 3.5 +/- 1.6 cm (0.7 - 8.6 cm). Sixty-four cases had 140 nodules 3.0 cm in diameter. Forty-seven patients had single nodule, 44 patients had 2 nodules, and 93 patients had 3 or more nodules. Fifty-seven patients had tumor of low differentiation, 53 had tumor of middle differentiation, and 18 had highly differentiated tumors. Kaplan-Meier method was used to calculate the cumulative survival rate. Statistical comparison of the effects of potential predictive factors on survival rate was performed using log-rank analysis. Multivariate analysis of the survival rates was performed by using Cox's proportional hazard model. RESULTS: The 1, 2, 3, 4, and 5-year cumulative survival rates of all 128 patients were 90.88%, 73.84%, 51.09%, 36.14%, and 31.89% respectively. Univariate analysis showed that tumor size (P = 0.028), tumor differentiation (P = 0.026) and local recurrence or new metastases (P < 0.001) significantly affected the survival. Multivariate analysis revealed that tumor size (P = 0.035), recurrence or new metastases (P = 0.001) and tumor differentiation (P = 0.038) each had a significant effect on survival. CONCLUSION: There is a significantly higher probability of long-term survival for patients with well-differentiated tumors 3.0 cm or less in diameter and without recurrence or new metastasis after percutaneous microwave ablation.