Breast cancer incidence is higher in high-income countries, because of its links with several risk factors [16
] and the presence of systematic screening policies [17
]. However, a decreasing trend has been observed since 2003 due to the decreasing use of HRT [18
]. Lower incidence rates in low-income countries probably reflect international variation in hormonal factors and accessibility to early detection facilities [19
Screening practices in Brazil were outlined by the Brazilian National Cancer Institute [21
] and have been followed by the states and municipalities. Screening guidelines include biannual mammography for women aged 50 to 69 years, and have been made public through occasional media campaigns.
In the study period, increasing CRs and ASRs were observed (Table
). In 1996, the ASR was 49.6/100,000 (95% CI: 39.2 to 60.0). In the following years, it had some fluctuation before becoming stable with rates higher than 60.0/100,000 in the last years of the series. Rates as high as these have been observed in other mid-income countries [22
] and could be justified in an area with an intermediate HDI such as Aracaju.
Increasing trends (Table
) were observed in the study, with an ASR-APC of 2.9 (95% CI: 1.1 to 4.6) and a CR-APC of 4.1 (95% CI: 2.0 to 6.3). Incidence rates were higher in peri- and postmenopausal women, with increasing trends in the groups aged 45–54 (APC: 3.9, 95% CI: 1.4 to 6.6) and 55–64 (APC: 5.6, 95% CI: 1.8 to 9.6) years. In the study community, formal screening invitations are not conducted. Rather, mammography is offered to women when they present to their health care practitioner because of other health problems, or even to request screening. This might somehow reflect the increasing trends in these age groups. Screening has been more consistently available since the early 1990s, when breast specialists began practicing in this community. In addition, first generation high-resolution breast imaging has also become available. Screening guidelines were established in 2004 on a biannual basis for women aged 50 to 69 years. The number of women in different age groups actually being screened is unknown. Furthermore, the role of HRT could not be established and might be worthy of future research.
Mortality rates are higher in high-income countries, but with decreasing trends, with a median ASR of 15.3/100,000 [22
]. In the United States, for instance, mortality rates standardized by the American population varied from 21.5/100,000 to 28.0/100,000, depending on the state, but have also presented decreasing trends [24
]. Low-income areas have shown a median ASR of 10.0/100,000, but with increasing trends [22
]. Possible explanations for this are the low incidence rates observed in those areas, and the lack of risk factors typically seen in high-income countries. Regarding increasing trends, inefficacy to detect less advanced tumors and lower accessibility to treatment facilities were suggested [19
]. In our study, crude and age-standardized mortality rates fluctuated throughout the years. A mean age-standardized mortality rate of 14.7/100,000 was observed in the 1996–2006 period. No significant trends were observed, with an ASR-APC of 3.0/100,000 (95% CI: -2.8 to 9.1) and CR-APC of 3.9 (95% CI: -2.2 to 10.3). However, there has been an increasing trend for the group aged 55–64 years, with an APC of 11.3 (95% CI: 1.1 to 22.4), probably reflecting the trend of increasing incidence in the peri- and postmenopausal periods. Actual cause of death has been a matter of discussion, because it has not always been adequately interpreted. In our study, breast cancer death was considered when it was certified as the underlying or contributing cause.
The mortality-to-incidence ratio has been advocated as a proxy for cancer survival, taken by 1-(M/R) [25
]. Mortality-to-incidence ratios around 0.24 have been observed in high-income countries, compared with 0.40 in less developed and 0.60 in low-income areas such as Africa [26
]. In the present study, a mean ratio of 0.27, which is similar to those of high-income areas, is rather satisfactory, but might be confirmed more accurately by survival studies.
It has been suggested that systematic screening, together with implementing better treatment facilities is the key to decreasing mortality rates [27
], but screening is sometimes contested because of the high cost of establishing mammography equipment, the low yield of biopsies, the lead time bias, and the diagnosis of lesions that would never become invasive [17
The Population-Based Cancer Registry of Aracaju has registered incident cancer cases in the State of Sergipe and has then selected cases from the area of Aracaju. This has resulted in a delay to close the annual database and case ascertainment has been more tedious. There have been some cases for whom place of residence could not be determined. Even after examining all sources and databases, a few cases still had to be excluded. The data were retrieved from several different sources of information, and some cases could be found in more than one information source; therefore, extra care had to be exerted to avoid duplication. Mortality rates were calculated from death records of the Official State Mortality Database. The cause of death has been criticized as being inadequately precise, mainly in developing areas, which jeopardizes our conclusions. However, official data were used and all possible effort was put into improving the quality of information.