Breast cancer incidence in a large cohort of Peruvian women affiliated to a pre-paid system.

Abstract

e12570 Background: Breast cancer (BC) is the second most common malignancy and the leading cause of death by cancer in Peruvian women (age-standarized rate [ASR] of 34 new cases/100,000 women estimated by GLOBOCAN 2008). The purpose of this study was to assess the incidence of BCin acohort ofwomenat Oncosalud, an oncologic pre-paid system that currently has 600,000 affiliates. Methods: We evaluated a dynamic cohort (period 1989 to 2011) of women affiliatedat Oncosalud – AUNA, an oncologic prepaid system.The crude incidence rate per year (number of new cases/women at risk), the specific rate according to age (number of new cases / persons-year) and cumulative risk were calculated. Results: Overall, during the assessment period, the BC incidence rate per year was 175.6 and the ASR incidence was 111.9 per 100,000 affiliates respectively. In our cohort of affiliates there were no BC cases before 1993 (with 907 women at risk for that year). The highest incidence rate was 177.6 registered in 1997 (11,822 women at risk). Incidence rates started decreasing in 2003 (169.2 with a population at risk of 39,593 women). The lowest incidence was 71.5, registered in 2011 (279,680 women at risk).According to age-groups, there were no BC cases under20 years old. Specificincidence ratesper age-group increases from the 30 year old-group (55.8). The peak of BC incidence was between 70 to 74 years old (407.4). In the same way, the cumulative risk increases after 30 years old. Conclusions: In our cohort of affiliates, the incidence of BC is greater than the general population, it could be due to the process of negative selection; however, specific incidence rates per age-group and cumulative risk are increased after 30 years, as seen in the general population.