Incidence and prognosis of liver metastasis at diagnosis: a pan-cancer population-based study

Metastasis is a major cause of cancer-related death and liver metastasis (LM) is a distinct type for its relatively good prognosis after timely treatment for selected patients. However, a generalizable estimation of incidence and prognosis of LM is lacking. Cancer patients with known LM status in the Surveillance, Epidemiology and End Results database were enrolled in the present study. The incidence and prognosis of LM were calculated by primary cancer type and clinicopathological factors. Among 1,630,725 cases, 105,329 (6.46%) cases present LM at diagnosis, with a median survival of 4 months. LM presents at diagnosis in 39.96% of pancreatic cancer, 16.00% of colorectal cancer (CRC) and 12.68% of lung cancer. Of all LM cases, 25.58% originated from lung cancer, with 24.76% from CRC and 17.55% from pancreatic cancer. LM originated from small intestine cancer shows the best prognosis (median survival: 30 months), followed by testis cancer (25 months) and breast cancer (15 months). Subgroup analyses demonstrated disparities in incidence and prognosis of LM, with higher incidence and poorer prognosis in the older population, African American, male, and patients with inferior socioeconomic status. The current study provides a generalizable data resource for the epidemiology of LM, which may help tailor screening protocol, design clinical trials and estimate disease burden.