Breast neoplasm in the state of Rio de Janeiro: ecological study of cases diagnosed in the last decade and correlation with screening measures

Introduction: In Brazil, breast cancer has been the most frequent oncological diagnosis among women, with the exception of non-melanoma skin tumors, with an estimated 73,610 new cases for each year from 2023 to 2025. Therefore, it is important to study the behavior of the disease to understand efficient strategies to increase detection rates.

Objectives: To statistically evaluate the correlation between breast cancer diagnosis rates in the state of Rio de Janeiro, mammogram rates and the percentage of BI-RADS 5 reports among the seven BI-RADS categories, as well as the trend time of these elements.

Methodology: For this ecological study, data were collected from 2014 to 2023 from the Sistema de Informações de Câncer and the Instituto Brasileiro de Geografia e Estatística, via the DATASUS platform. Using the Statistics Kingdom software, Spearman’s test was performed to evaluate the correlation between the variables, and simple linear regression was used to evaluate their temporal trend. The variables are: rate of breast cancer diagnoses per location of diagnosis per 10,000 inhabitants, rate of mammograms performed by place of care per 10,000 inhabitants and percentage of BI-RADS 5 reports.

Results: Linear regressions indicated the presence of a positive linear correlation between year and rate of mammograms (p<0.05; R²=0.68), as well as between year and rate of diagnoses (p<0.05; R²=0 .84), with an increase of 1.9 mammograms and 22.2 diagnoses per 10,000 inhabitants per year respectively. This test did not reveal a linear correlation between year and percentage of BI-RADS 5 (p>0.05; R²=0.24). At the same time, the Spearman test indicated that there is a positive correlation (p<0.05; r=0.74) between the rates of mammograms performed and breast cancer diagnoses.

Conclusion: In view of the above, there is a correlation between the variables mammography rate and diagnosis rate, as well as an increasing trend for both. Unlike them, the percentage of BI-RADS 5 did not show such a trend. These results may suggest that the increase in breast cancer diagnosis rates in the state of Rio de Janeiro is being influenced more by the intensification of screening measures, and not by possible increases in the incidence of the disease. This may also suggest the importance of policies to encourage and facilitate mammograms, such as Outubro Rosa and the Programa Nacional de Controle do Câncer de Mama.

Corresponding author: Hugo Antunes Macedo (e-mail: hugoantmac@hotmail.com).