Changing Incidence/Age for BCa in Taiwan

#A163 Rapidly Changing Incidence and Age-Distribution of Female Breast Cancer in Taiwan during 1980-1999.

Ying-Chun Shen,1 Chee-Jen Chang,2 Chang-Fang Chiu,1 Ann-Lii Cheng.3

Hemato-Oncology Division, Internal Medicine Department, China Medical College H,1 Taichung, (Nil), Taiwan, Department of Medical Research, National Taiwan University Hospital,2 Taipei, Taiwan, Departments of Oncology and Internal Medicine, National Taiwan University Hospital,3 Taipei, Taiwan.

Background: Female breast cancer (FBC) in Taiwan is characterized by a striking rise of the incidence (triple in the past 20 years) and a relative young median age (45-49 y/o) at diagnosis.

These features are in sharp contrast to most developed Western countries. Since Taiwan is a rapidly westernized country in the past 40 years, we hypothesizes that the Western life style that is increasingly adopted by the younger generation may have an important impact on the rapidly changing incidence and age-distribution of FBC in Taiwan.

Materials and Methods: We compared the epidemiologic data of FBC during 1980 and 1999 in Taiwan and the American white population.Epidemiological data of FBC of Taiwanese were obtained from the Cancer Registry of Taiwan, Department of Health, R.O.C.( ).

For FBC of American white, the database of Surveillance, and Epidemiology, End Results (SEER) ( was adopted.

Age-specific incidences of FBC were plotted by calendar year at diagnosis and by birth cohort. Average annual percent change was estimated by the simple log-linear model for evaluation of secular trend. Effects of time period and birth cohort other than age were evaluated by age-period-cohort model.

Results: While the incidences of FBC in the older age groups (?50 y/o) were much higher in the American white population than Taiwanese, the differences were much smaller in the younger age groups (< 50 y/o).

The incidence was almost identical between the two populations for the age group of 30-34 y/o. In Taiwanese women younger than 50 y/o, the incidences of FBC were approaching that of American white; and this trend appeared to be the results of later cohorts in which they were born.

Furthermore, we demonstrated a very strong cohort effect and a minimal period effect on the secular trend and age-distribution pattern of FBC in Taiwan.

Conclusions: The younger generation of Taiwanese, in contrast to their parents, has a rapidly increasing risk of FBC, which is approaching that of the American whites. The cohort effect corresponded to the westernization of life style in Taiwan since mid-1960.

We anticipate that when these younger Taiwanese women, who were born after 1970 and have been living an almost completely westernized life style, grow older, the incidence and age-distribution of FBC in Taiwan will become more and more similar to that of the American white population.

Frontiers in Cancer Prevention Research, 2003 AACR

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