Factors that influence the incidence of breast cancer in Arica, Chile (Review).

Breast cancer is a common disease estimated to occur in 1 in 9 women over their lifetime. Epidemiological research has identified a number of risk factors for breast cancer. Racial and ethnic differences in breast cancer mortality rates have been difficult to ascertain. The present review reports that there was an increase in the incidence of breast cancer in Arica, Chile, from 1997 to 2007, particularly in 2005, reaching 55.1% per 100,000 women, while the percentage decreased in 2006 and 2007. A greater percentage of breast cancer was found in individuals between 46 and 65 years of age when the population was distributed by age. The Indian population, Aymara, had only a 13.9% incidence of the disease. The incidence for breast cancer for patients with no family background reached approximately 88%, with or without Indian ethnicity, and 98.4% of these women did not have prior hormonal therapy. When the stage of the disease and the number of pregnancies were considered, results showed that there was an increase in the progression of the disease from stage I to stage III in women that had 1-3 pregnancies. Results also showed that 20.9 and 33.2% who received prior tamoxifen treatment were in stages I and IIA, respectively. The breast cancer incidence reached 42.4% when patients had a sister with the disease. It can be concluded that important differences in the risk factors of breast cancer should be identified in the future for a comparison with other biological factors, such as genetic and molecular factors. This may provide greater insight into breast cancer aetiology in different populations.