New research from USC Norris Comprehensive Cancer Center has discovered that immigrant adults with liver cancer in the U.S. have higher survival rates than people with the disease who were born in the U.S.
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.
Prior 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 USC Norris study, 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 finding is important, as liver cancer rates are rising among U.S.-born,” said study author Kali Zhou, MD, a member of the Cancer Epidemiology Program at USC Norris and a transplant hepatologist specializing in the treatment of chronic liver disease at Keck Medicine of USC.
“Understanding why immigrants have better outcomes may help us create strategies to improve the survival of those born here.”
California data studied for survival rates based on nativity and race/ethnicity
This study is one of the first to robustly address nativity status as a predictor of overall survival for adults with HCC, and it provides important estimates of HCC survival by region of birth.
Zhou and her colleagues 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.
California has a high concentration of immigrants, representing about a quarter of the foreign-born population nationwide.
The study 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 born in foreign countries.
The population-based registry provided a unique opportunity to compare HCC survival by nativity overall, separated by regions of origin within individual race and ethnicity groups.
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 Eastern Europe and Greater Middle East compared to West/South/North Europe for whites.
The path to improving treatment approaches
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.
According to Zhou, research has increasingly demonstrated the importance of social determinants of health to the diagnosis and treatment of cancer. A patient’s place of birth is one aspect of social background that could warrant a closer look.
“Birthplace is likely closely linked to socioeconomic status, cultural beliefs and social networks — all elements that may ultimately impact cancer outcomes,” Zhou said. “Assessing these social determinants with each patient will allow clinicians to better tailor resources and decision-making to help achieve the best outcomes.”
The new study indicates that greater care may be needed when addressing treatment plans for patients born in the U.S.
“We shouldn’t assume that U.S.-born patients have complete understanding or fewer barriers to care just because they may appear on the surface to be able to better navigate the health care system,” Zhou said.