Temporal changes in breast cancer screening coverage provided under the Brazilian National Health Service between 2008 and 2017
Publicação importante do grupo de pesquisadores goianos da Universidade Federal de Goiás.
Danielle Cristina Netto Rodrigues1, Ruffo Freitas-Junior1, Rosemar Macedo Sousa Rahal1, Rosangela da Silveira Corrêa1, Pollyana Alves Gouveia1, João Emílio Peixoto2, Edésio Martins3 and Leonardo Ribeiro Soares1
Background: In Brazil, 70% of the population depends on the public healthcare system. Since early detection is considered crucial, this study aimed to evaluate temporal changes in breast cancer screening coverage provided under the Brazilian National Health Service (SUS) according to the different regions of the country between 2008 and 2017.
Methods: This ecological study analyzed data on breast cancer screening within the SUS for women aged 50–69 years. Coverage was calculated from the ratio between the number of screening tests conducted and the expected number for the target population. Joinpoint regression analysis was used to calculate annual percent changes (APC) in coverage.
Results: Around 19 million mammograms were performed in 50–69-year old women within the SUS between 2008 and 2016. The estimated APC indicates that breast cancer screening coverage increased by 14.5% annually in Brazil between 2008 and 2012 (p < 0.01), with figures stabilizing between 2012 and 2017 as shown by an APC of ? 0.4% (p = 0.3). In the five geographic regions of the country, the APC initially increased, then stabilized in the north, northeast and southeast and decreased in the south and Midwest. Of the 26 states, coverage increased in seven and remained stable in six. In the other 13, there was an initial increase followed by stabilization in 11, and a reduction in coverage in two. In the Federal District, coverage remained stable throughout the study period.
Conclusion: Evaluation of the temporal changes in breast cancer screening coverage provided under the Brazilian National Health Service revealed an initial increase, confirming that public policies were effective, although insufficient to ensure organized screening. There appears to be a lack of uniformity between the different regions and states and this situation is highlighted in the final 5-year period, with the APC reflecting stabilization of breast cancer screening coverage.
Keywords: Breast cancer, Screening programs, Mammography, Healthcare coverage, Brazilian National Health Service
* Correspondence: firstname.lastname@example.org
1Brazilian Breast Cancer Research Network, Advanced Center for Breast Diagnosis (CORA), School of Medicine, Federal University of Goiás, Primeira Avenida, s/n, Bloco II, Setor Universitário, Goiânia, Goiás 74605-020, Brazil.
Full list of author information is available at the end of the article
Several randomized clinical trials conducted between the 1960s and the 1990s have reported a reduction in mortality from breast cancer of up to 40% in the female population of 50–69 years of age submitted to breast cancer screening [1–3]. In geographical regions with limited financial resources and difficulties in accessing standard oncological treatment [4–6], this strategy may represent an opportunity for more conservative treatments and better clinical outcomes [7–9].
Despite the lack of population-based screening policy in Brazil [10–12], the disparity between access to screening within the public healthcare system, on which 70% of the Brazilian population relies, and access to screening within the private healthcare system is evident. The incidence of tumors diagnosed at advanced stages reflects this situation, since 36.9% of such cases occur in women consulting within the public healthcare network, while in the private sector this rate falls to 16.2% [13–15]. Nevertheless, this scenario has changed over recent decades, with declining mortality rates in some states of the country, possibly due to advances in the treatment of the disease .
Another factor that could have contributed to this stabilization was the development of programs such as the National Mammography Quality Program (PNQM) and the Cancer Database (SISCAN) [17, 18]. These initiatives aimed to improve the monitoring of the quality and reporting of test results, and patient follow-up. This represented an important step forward for public policies in the country [19, 20].
Nevertheless, there remains a need to improve such public policies. Because early diagnosis represents an important step in this process, the present study was developed to evaluate temporal changes in breast cancer screening provided under the Brazilian National Health Service (SUS) in accordance with the different regions of the country and the different states including the federal district, between 2008 and 2017.
This was an ecological time-series study in which data referring to mammograms conducted within the SUS were analyzed, for the country as a whole, each geographic region, the states and the federal district, for the period between 2008 and 2016. Brazil consists of 26 states and a federal district, with these areas being grouped together into five geographic regions: the north, northeast, southeast, south and Midwest .
The target population consisted of women of 50 to 69 years of age, according to the regulations of the Ministry of Health of Brazil . Data regarding the population of women between 2008 and 2012 were collected from the System of Demographic and Socioeconomic Information on Health, Department of Information Technology of the SUS (DATASUS) . The projected population of Brazil established by the Brazilian Institute of Geography and Statistics (IBGE) was used for the 2013–2016 period .
Breast cancer screening coverage was estimated based on two-yearly screening aimed at reaching 100% of the target population. Coverage was expressed as a percentage and calculated from the ratio between the number of scans performed and the expected number for the target population .
The number of exams carried out annually between 2008 and 2017 was obtained from the DATASUS outpatient database  according to the codes for the procedure: 0204030030 (mammography) and 0204030188 (bilateral mammography for screening purposes). The expected number of exams for the target population was calculated from the total number of women of 50–69 years of age and in accordance with the recommendations of the National Cancer Institute (INCA) for twoyearly screening .
The annual percent change (APC) in breast cancer screening coverage was calculated for Brazil as a whole, its different geographic regions, each state and the federal district. The relevant 95% confidence intervals (95%CI) were calculated, with p-values < 0.05 being considered statistically significant. The Poisson regression model was used for these calculations and the software program used was JoinPoint Regression, version 22.214.171.124 of June 2015 (National Cancer Institute) .
For analysis purposes, mammography coverage was considered to have increased when the APC increased, and the minimum value of the confidence interval was above zero. Coverage was considered to have decreased when the APC decreased, and the maximum value of the confidence interval was below zero. Coverage was considered to have remained stable when, irrespective of the rate of coverage, the minimum value of the confidence interval was below zero and the maximum value was above zero.
The data used are publicly available [24, 25]. For this type of study, formal consent is not required. All recommendations of good clinical practice were followed according to Brazilian law and the Helsinki Convention.
In 2008, the female population of 50 to 69 years of age in Brazil was estimated at 14,432,692 women. This number increased to 19,584,342 in 2017, representing an increment of 36.0% in this population. Over that timeframe, a total of 1,227,514 and 2,790,937 mammograms, respectively, were approved for payment. This represents an increase of 127.0% in the number of exams paid for by the SUS, at a total cost of 968,567,514.42 Brazilian reais.
The estimated extent of breast cancer screening coverage provided under the SUS in Brazil for the 2008–2017 period ranged from 14.4 to 24.2%. Table 1 shows the estimated coverage per year for the entire study period according to the different geographic regions, the states and the federal district.
Table 1 Breast cancer screening coverage provided under the Brazilian National Health Service, for the country as a whole, its different geographic regions, states and the federal district for women of 50-69 years of age between 2008 and 2017
Regression analysis showed that, for Brazil as a whole, there was a significant increase in breast cancer screening coverage, with an APC of 14.5% (p < 0.01) for the 2008–2012 period, while for the 2012–2017 period coverage remained stable (p=0.3) (Fig. 1). The same was true for the different regions of the country, with the analysis showing a significant increase in breast cancer screening in the north, northeast and southeast at the beginning of the study period, with APCs of 11.1, 14.4 and 14.1%, respectively (p<0.01), followed by stabilization (Fig. 2a, b and c).
In the south and Midwest, however, the increase occurred between 2008 and 2011 and between 2008 and 2013, with APCs of 21.0 and 9.4%, respectively (p < 0.01). Nevertheless, after this period, there was a reduction in breast cancer screening coverage, with an APC of ? 2.0% (p<0.01) in the south and ? 9.4% (p < 0.01) in the Midwest (Fig. 2d and e).