OBJECTIVE - Chinese women residing in Asia and Hawaii have low consumption of tobacco but a high incidence of lung cancer. To explore this question further, we conducted a study of lung cancer among Chinese women residing in mainland US.
METHODS - Using data from NCI's SEER program, we identified residents of Los Angeles County, the San Francisco Metropolitan Area, and the Seattle-Puget Sound Area who were 50 years or older, diagnosed with cancer of the lung or bronchus in 1999-2001, with race specified as non-Hispanic white (n = 18,493), Chinese (n = 853), Filipino (n = 615), or Japanese (n = 282). The sex-specific observed number of lung cancer cases among each Asian sub-group was compared to the expected number of lung cancer cases for each Asian sub-group. The expected number was determined by multiplying the age-, sex-, and geographic area-adjusted incidence rates for non-Hispanic whites by the age- and sex-specific ratio of percentage of current smokers in each Asian sub-group to whites in 1990, and then by the size of the respective Asian populations.
RESULTS - Chinese women had a four-fold increased risk of lung cancer, and Filipino women a two-fold increased risk, compared to that expected based on rates in US non-Hispanic whites with a similar proportion of cigarette smokers. Lung cancer among Chinese, Filipino, and Japanese males, as well as Japanese females, did not deviate from expected risk. Among Chinese women, the increased risk was largely restricted to adenocarcinoma and large cell undifferentiated carcinoma.
CONCLUSIONS - Chinese female residents of the western US mainland have a much higher risk of lung cancer than would be predicted from their tobacco use patterns, just as they do in Asia.