Influence of thermal ablation of hepatic metastases from gastric adenocarcinoma on long-term survival: Systematic review and pooled analysis

The objectives of this systematic review and pooled analysis were to examine long-term survival, morbidity, and mortality following thermal ablation of gastric cancer hepatic metastases and to identify prognostic factors that improve survival. Patients with hepatic metastases from gastric cancer are traditionally treated with palliative chemotherapy. Surgical resection is an alternative treatment of hepatic metastases. Whether patients can obtain benefit from thermal ablation of hepatic metastases is still controversial. A systematic literature search was undertaken (1990–2018). Publications were included if they studied more than 7 patients undergoing thermal ablation for hepatic metastasis from gastric cancer in the absence of peritoneal disease or other distant organ involvement. The primary outcome was the hazard ratio (HR) for overall survival. Comparison between thermal ablation and systematic chemotherapy or hepatic resection had been carried out. The influence of liver metastasis-related factors, such as <3 cm versus >3 cm, single versus multiple and metachronous versus synchronous upon survival was also assessed. The median survival of thermal ablation for the 12 studies included was 22.93[20.45–25.41] months. Procedures were associated with a median 30-day morbidity of 6% (0%–23%) and with no mortality. The median 1-year, 2-year, 3-year, and 5-year survival were 79.14%, 39.79%, 28.45%, and 19.46%, respectively. Thermal ablation of hepatic metastasis was associated with improved overall survival compared with systematic chemotherapy (HR = 2.12; 95% CI 0.77–3.47; P=.000). Meta-analysis confirmed the additional survival benefit of size <3 cm (HR = 1.46; 95% CI 1.03–1.88; P = .002) and receiving chemotherapy after thermal ablation (HR = 2.14; 95% CI 1.05–3.23; P = .000). A use of RFA/ microwave ablation (MWA) as a liver-directed treatment may provide greater survival benefit than chemotherapy and is an alternative option for the treatment of liver-only metastases from gastric cancer. With the appropriate selection of patients, such as tumors <3 cm in diameter, thermal ablation may provide better prognosis than hepatic resection of hepatic metastasis with lower morbidity and mortality. Postoperation chemotherapy should be provided to patients with GLM who received thermal ablation.