Surgery for liver metastases from primary melanoma: a systematic review and meta-analysis

Background: Historically, liver metastases due to melanoma have been associated with dismal prognosis. Moreover, the actual survival benefit from the treatment of melanoma liver metastases is still controversial. Hence, this study aims to evaluate the difference in surgical versus non-surgical options for melanoma liver metastases. Methods: Four databases (PubMed, EMBASE, Scopus, and Cochrane Library) were searched from inception to July 17, 2022. Studies were included if they compared outcomes between surgical and non-surgical treatment for patients with liver metastases from resectable melanoma. Meta-analyses were performed for the outcomes of 1-year, 2-year, 3-year and 5-year OS. Sensitivity analyses were performed for outcomes with substantial statistical heterogeneity. To account for possible moderators that might contribute to statistical heterogeneity, univariate meta-regression with mixed-effects models and subgroup analyses were conducted for the outcome of 2-year OS. Results: The search yielded 6610 articles; 13 studies were included in our analysis. Meta-analyses showed that survival outcomes were in favour of patients undergoing surgery as compared to non-surgery: 1-year OS (HR = 0.29, 95%CI 0.19–0.44, p < 0.00001), 2-year OS (HR = 0.19, 95%CI 0.09–0.38, p < 0.00001), 3-year OS (HR = 0.07, 95%CI 0.03–0.19, p < 0.00001) and 5-year OS (HR = 0.07, 95%CI 0.02–0.22, p < 0.00001). All included studies were of high quality. There was moderate-to-high statistical heterogeneity. Findings were robust to sensitivity analyses. Subgroup analyses and univariate meta-regression revealed neoadjuvant therapy and age as statistically significant subgroup and moderator respectively. Conclusions: This study suggests that surgical treatment of melanoma liver metastases could offer better OS outcomes compared with non-surgical treatment.