Environmental pressures, tumor characteristics, and death rate in a female breast cancer cohort: a seven-years Bayesian survival analysis using cancer registry data from a contaminated area in Italy.

Introduction: In Taranto, Southern Italy, adverse impacts on the environment and human health due to industrial installations have been studied. In the literature, few associations have been reported between environmental factors and breast cancer mortality in women. The aim of this study was to investigate the relationships between residence in areas with high environmental pressures, female breast cancer characteristics, and death rate. Methods: Data from the Taranto Cancer Registry were used, including all women with invasive breast cancer diagnosed between 01 January 2015 and 31 December 2020 and with follow-up to 31 December 2021. Bayesian mixed effects logistic and Cox regression models were fitted with the approach of integrated nested Laplace approximation, adjusting for patients and disease characteristics. Results: A total of 10,445 person-years were observed. Variables associated with higher death rate were residence in the contaminated site of national interest (SIN) (HR 1.22, 95% CrI 1.01-1.48), pathological/clinical stage III (HR 2.77, 95% CrI 1.93-3.97) and IV (HR 17.05, 95% CrI 11.94-24.34), histological grade 3 (HR 2.50, 95% CrI 1.20-5.23), Ki-67 proliferation index of 21-50% (HR 1.42, 95% CrI 1.10-1.83) and > 50% (HR 1.81, 95% CrI 1.29-2.55), and bilateral localization (HR 1.65, 95% CrI 1.01-2.68). Variables associated with lower death rate were estrogen and/or progesterone receptor positivity (HR 0.61, 95% CrI 0.45-0.81) and HER2/neu oncogene positivity (HR 0.59, 95% CrI 0.44-0.79). Discussion: The findings confirmed the independent prognostic values of different female breast cancer characteristics. Even after adjusting for patients and disease characteristics, residence in the SIN of Taranto appeared to be associated with an increased death rate.