Breast cancer is surging among Asian American women — and scientists don’t know why

A new study led by UC San Francisco has found a sharp rise in invasive breast cancer among Asian American women over the past two decades. This increase is happening across almost every Asian American ethnic group, and it's happening faster than in any other U.S. ethnic group. The trend is especially noticeable among younger women and those with advanced or aggressive forms of the disease.

The research, published in JAMA Network Open, shows that breast cancer rates in Asian American women have climbed by more than 3% each year. The jump was even steeper among Chinese and Vietnamese women. Native Hawaiian women currently have one of the highest breast cancer rates in the U.S., but their rates only increased by about 1% annually, which is much slower than the other groups.

Experts believe that better breast cancer screening is not the reason for this trend. In fact, the fastest increases were seen in more advanced cancers that had already spread. One particularly alarming finding was a more than 6% annual rise in triple-negative breast cancer cases among Chinese American women between 2017 and 2022.

These troubling patterns highlight the need to treat Asian American, Native Hawaiian, and Pacific Islander women as distinct populations. The study's senior author, Scarlett Lin Gomez, PhD, emphasizes the importance of focusing on these disparities. Understanding what's driving the increase in younger women is still unclear, but factors like changes in lifestyle and diet may play a role, though they don't fully explain the trend.

Two UC San Francisco-led projects, CRANE and ASPIRE, aim to uncover more answers. Researchers hope these studies will shed light on why breast cancer is rising so rapidly in these communities and ensure all women have access to culturally appropriate education, screening, and timely follow-up care.