The levels of trace elements in the serum of postmenopausal breast cancer patients were determined and correlated with Tumour Parameters Index (TPI) ,developed for this study, in order to study their contributions in breast cancer diagnosis and evaluate their prognostic value. Serum zinc, selenium, lead, iron, copper, cadmium were estimated using atomic absorption spectrophotometry in 63 newly diagnosed postmenopausal breast cancer patients and compared with 63 apparently healthy controls. TPI was derived by a composite of six parameters that are conceptually relevant to tumour characteristics on a maximum 15-point scale and normality was assured. The results showed significantly higher mean levels of Pb(ug/L) (71.02±0.01)(p<0.0001) and Cd(ug/L) (0.26±0.03) in postmenopausal women with breast cancer than controls (52.03±0.02; 0.16±0.03) respectively (p<0.03). On the other hand, a significant decrease was observed in mean levels of Zn(ug/ml) (0.75±5.08 vs 1.04±3.19), Se(ug/L)(44.01±5.01 vs 69.37±4.6), Fe(ug/dl) (59.99±4.33 vs 82.94±1.71) and Cu (ug/dl) (84.51±2.39 vs 191.30±13.23) of postmenopausal women compared to the controls respectively. Multiple regression analysis showed that Pb and Cd were significantly positively correlated with TPI(β = 0.826; p < 0.0001) and the R2-values showed that 67.6% and 4.5% of variations observed in the outcome variable can be accountable to serum levels of the two trace elements respectively. Furthermore, Zn, Se, Fe and Cu were significantly inversely correlated with tumour parameters in such a way that 19.4%, 6.20%, 48.6% and 61.3% of variations observed in the outcome variable can be accountable to serum levels of Zn, Se, Fe and Cu respectively. Decrease in serum levels of Fe, Cu, Se, Zn and increase in levels of Pb and Cd may have potential value in predicting diagnosis and prognosis of breast cancer.
