Factors associated with locoregional and metastatic breast cancer at diagnosis in a Southern Portuguese registry in the period 2005-2012

Breast cancer (BC) is the most frequent malignancy in Portuguese women, and more than half of the registered cases live in the south of the country. The main of this study was to characterize patients with locoregional and metastatic incident BC living in the Southern Portuguese and Madeira regions in 2005-2012 according to demographic, clinical and contextual characteristics. Additionally it aimns to find the associations and relative influences of these factors with locoregional or metastatic disease at diagnosis. After a descriptive approach, binary logistic regression models were used to estimate factors related to the presence of metastatic disease at diagnosis. A final multiple regression model was developed and presented graphically as a nomogram. The median age at diagnosis was 60.84 years, being statistically lower in locoregional cases (P<0.001). Most patients presented a locoregional disease (78.4%) of unspecified location (44.5%) and had a ductal carcinoma (73.1%). The Lisbon region represented 50.5% of the analyzed cases. Metastatic disease significantly decreased over the period under analysis (≈7%/year). Demographic (age at diagnosis ≥50 years), clinical (lobular and 'other' morphologies, unspecified location) and contextual (residence in Portalegre) characteristics were statistically correlated with the presence of metastatic disease at the time of BC diagnosis in univariate logistic regression, with all but the last maintaining their significance in a multivariate model. Cases with metastatic BC disease at diagnosis are decreasing; however, additional information on their characteristics can improve the alignment of public health strategies, thus strengthening this trend, and contributing to the development of a graphically tailored screening tool.