Abstract: Objective: To explore the clinical epidemiological characteristics and survival outcomes of patients with multiple primary malignant tumors (MPMTs) combined with liver cancer.
Methods: From August 2010 to June 2023, patients with liver cancer were selected from malignant tumor patients admitted to the Cancer Center of Peking University Third Hospital. The basic information of the patients and the incidence information of liver cancer and other tumors were collected to make comparisons between MPMTs and single liver cancer, also groups with liver cancer as the first or the second primary cancer.
Results: The incidence of liver cancer combined with extraneous tumors was accounting for 13.1% (23/176) of liver cancer patients during the same period. Among the patients, 5 had synchronous multiple primary tumors, and 18 had metachronous multiple primary tumors. Of these patients, 9 had liver cancer as the first primary tumor, and 9 had liver cancer as the second primary tumor. Liver cancer patients with family history of cancer were more likely to have multiple primary tumors (χ²=5.22, P=0.030). Liver cancer as the first primary tumor had a shorter interval for multiple primary tumor onset compared to liver cancer as the second primary tumor (35 month vs. 156 month, P=0.009). The onset interval was negatively correlated with the diagnosis age of the first primary tumor (r=-0.60, P=0.009).
Conclusions: Multiple primary tumors associated with liver cancer tend to occur in patients with a family history of cancer. There was a difference in the tumor incidence interval between multiple primary cancers with liver cancer as the first primary tumor and multiple primary cancers with liver cancer as the second primary tumor.

Key words: Liver cancer, Multiple primary tumor, Family tumor history, Metachronous, Pathogenetic sequence