University of Southern California study shows immigrant adults with liver cancer possess survival rates than those born in the US

Immigrant adults with liver cancer in the United States have higher survival rates than people with the disease who were born in the U.S., according to new research from the USC Norris Comprehensive Cancer Center.

Hepatocellular carcinoma (HCC), the most common form of liver cancer, contributes to more than 27,000 deaths annually in the United States. Immigrants comprise a significant proportion of those diagnosed with HCC in the U.S. Research has shown that birthplace, also referred to as nativity, impacts incidence and risk factors for HCC, but little was known about its influence on survival after diagnosis.

The new study, just published in the Journal of the National Cancer Institute, identified a previously unrecognized disparity in survival after a diagnosis of liver cancer across all major racial/ethnic groups, with immigrants having better survival compared to those born in the U.S. This study is one of the first to robustly address nativity status as a predictor of overall survival for adults with HCC and provides important estimates of HCC survival by region of birth.

“Liver cancer is one of few cancers with increasing deaths. We identified a novel disparity by birthplace, whereby immigrants with liver cancer demonstrated better survival than their U.S.-born counterparts,” said study author Kali Zhou, MD, member of the Cancer Epidemiology Program at the USC Norris cancer center and a transplant hepatologist specializing in the treatment of chronic liver disease at Keck Medicine of USC. “This was true across different racial/ethnic groups. This finding is important as liver cancer rates are rising among U.S.-born and understanding why immigrants have better outcomes may help us create strategies to improve the survival of those born here.”

California has a high concentration of immigrants, representing about a quarter of the foreign-born population nationwide. This study used California Cancer Registry data to investigate whether birthplace impacts survival among patients with liver cancer, a cancer with poor prognosis that is common among immigrants, though rising in those born in the U.S.

Zhou, who is also an Assistant Professor of Clinical Medicine at the Keck School of Medicine of USC, and her colleagues identified 51,533 adults with HCC with available birthplace data in the California Cancer Registry between 1988 and 2017, of which 20,400 were people who were born in foreign countries. Cases were categorized as people who are born in the U.S. or people born in any other country, then stratified by four mutually exclusive race and ethnicity groups: Hispanic, non-Hispanic (NH) White, NH Black, and NH Asian/Pacific Islander. Results showed that 40% of all HCC cases were among those born outside of the U.S., and that their five-year survival rate was higher than patients with HCC who were born in the U.S. across all four major race and ethnicity groups. Among foreign-born people, lower mortality was observed in those from Central and South America compared to Mexico for Hispanics, East Asia compared to Southeast Asia for Asian/Pacific Islanders, and East Europe and Greater Middle East compared to West/South/North Europe for Whites.

The population-based California Cancer Registry provided a unique opportunity to compare HCC survival by nativity overall separated by regions of origin within individual race and ethnicity groups. Understanding the reasons for better survival among immigrants may help researchers address the disparity in survival rates by identifying ways to improve outcomes for people born in the U.S.

In addition to Kali Zhou, other contributors from the USC Norris Comprehensive Cancer Center and the Keck School of Medicine include Lihua Liu, PhD; Mariana Stern, PhD; Wendy Setiawan, PhD; Norah Terrault, MD, MPH; and Myles Cockburn, PhD.

This work was supported by the California Department of Public Health, the Centers for Disease Control and Prevention’s National Program of Cancer Registries, and the National Cancer Institute’s Surveillance, Epidemiology and End Results Program.