Possible local treatment for liver metastases of adenoid cystic carcinoma (ACC): single-centre experience and literature review

BACKGROUND: Adenoid cystic carcinoma (ACC) is a relatively indolent cancer, for which the major cause of death is distant metastases. The median survival time of patients with distant metastases of ACC is approximately 20 months. Although the liver is not the most common site of secondary ACC, effective treatment of liver metastases could improve patient survival. This study explored the clinical features and treatment of liver metastases of ACC in one centre and performed a literature review. METHODS: This is a retrospective cohort study. The records of 25 ACC patients with liver metastases in our hospital from January 2000 to September 2018 and 13 case reports (from 2000 to 2018) from PubMed published in English were reviewed together. Survival curves were estimated by the Kaplan-Meier method. Multivariate cox regression analysis was used to identify risk factors for overall survival (OS). RESULTS: Patients with liver metastases of ACC had a poor prognosis. The median survival time of patients with ACC liver metastases was 14 months (4–26 months), and the 1-, 2-, and 3-year survival rates were 55.8%, 28.5%, and 15.2%, respectively. Isolated liver metastases were more likely to benefit from local treatment, such as surgery and radiofrequency ablation (RFA), than multifocal metastases. The prognosis was worse for patients who received systemic treatment for multifocal liver metastases than for those who received other treatment. Synchronous liver metastases were the predictive factor for OS both in univariate and multivariate analysis. CONCLUSIONS: Local treatment, such as surgical resection or RFA, may prolong the survival time of ACC patients with liver metastases. The definition of resectability for liver metastases needs further investigation.