Breast cancer ranks second to stomach cancer as a primary cancer site. An increasing trend in mortality and morbidity of breast cancet has been shown since 1980s. Studies on migrant populations, in which higher incidences were shown than population in their motherlands, indicated the importance of environmental factors on breast cancer development. Older age, family history of breast cancer, early menarche, late menopause, late full-term pregnancy, never-having had a breast-fed child, and postmenopausal obesity were idenrified as risk factors in Korea. These are not different from risk factors detected in western countries. Nevertheless, a ^-shape age-specific incidences surve is shown in Korea shose incidence is relatively low. In western countries, where incidence rates are high, the incidences increase with age in a straight line. This difference may be explained by the "Estrogen-Augmented-:rogesterone Hypothesis" that is relevant to sex hormones. In fact, a nuch lower estradiol levels was reported in Korean women compared to those in American. On the other hand, genetic polymorphism is expected for future research on breast cancer etiology. Only preventive strategies based on epidemiology of breast cancer in Korea may effective to counter this malignancy in Korean women.
Breast Neoplasms* ; Breast* ; Child ; Epidemiology ; Estradiol ; Female ; Gonadal Steroid Hormones ; Hand ; Humans ; Incidence* ; Korea* ; Menarche ; Menopause ; Mortality ; Obesity ; Polymorphism, Genetic ; Pregnancy ; Risk Factors ; Stomach Neoplasms ; Transients and Migrants