Some Asian American communities experiencing high rates of certain cancers
California researchers are leading a nationwide effort to find out why rates of certain cancers are high in some Asian American communities.
It comes as health experts see rising rates of lung cancer and rising rates of early-onset breast cancer among Asian American women who have never smoked.
“Asian Americans are actually the first racial and ethnic group for whom cancer is the leading cause of death,” said Scarlett Gomez, a cancer epidemiologist at UC San Francisco and one of the leaders of the project.
UCSF is participating with researchers from UC Irvine, UC Davis, Cedars-Sinai and Temple University in launching a $12.5 million National Cancer Institute-funded study called the ASPIRE Cohort that will follow 20,000 Asian Americans over time. Researchers say this is the first large-scale longitudinal cancer study focused on Asian Americans.
As smoking rates have fallen across much of the United States, lung cancer cases have also declined. But researchers observed a slight increase among Asian Americans despite relatively low smoking rates, especially among women. More than half of Asian American women diagnosed with lung cancer are said to be non-smokers.
Many existing studies on lung cancer risk among nonsmokers were conducted in Asia, where exposure patterns may differ significantly from those in the United States, said Iona Cheng, a molecular epidemiologist at UCSF who also led the project.
Researchers know that outdoor air pollution, cigarette smoke and cooking oil fumes can contribute to lung cancer risk. However, it is unclear whether these can explain disease patterns among Asian Americans in the United States.
Rising breast cancer rates among Asian American women also add to this pressure.
“Early-onset breast cancer” diagnosed before age 50 is “growing fastest among Asian Americans,” Gomez said. Recent data shows rates among Asian Americans, Native Hawaiians and Pacific Islanders are approaching rates for non-Hispanic white women, he said. Cancer experts don’t know why.
One of the primary goals of the ASPIRE study is to move beyond treating Asian Americans as a single category. The term can encompass people with radically different exposure patterns and cuisines, with roots in dozens of countries from Sri Lanka to China’s border with Russia to the Pacific islands.
“When we break down and look at all the different Asian ethnicities, we see broad diversity,” Cheng said.
The incidence of thyroid cancer is higher in Filipino women, and stomach cancer is more common among some Koreans and Japanese. Combining all Asian Americans into a single category may make it impossible to detect these differences.
The study also aims to address long-standing gaps in representation. Although Asian Americans make up approximately 8% of the U.S. population, they have historically received little research funding.
Existing cancer studies often include too few Asian Americans to draw meaningful conclusions about specific ethnic groups, the researchers said. Salma Shariff-Marco, a social and behavioral scientist at UCSF who also leads the projects, helped make it difficult to demonstrate the need for more targeted research. The ASPIRE cohort was designed to demonstrate diversity by including a broader range of ethnic groups and more contemporary exposures than previous studies, he said.
