Comparative Assessment Of Essential And Toxic Metals In The Blood And Scalp Hair Of Head And Neck Cancer Patients Versus Controls

Abstract

Cancer incidence/mortality rates have been rising globally and numerous studies have shown that exposure to trace metals is the one of the major factors in the development of cancer. Therefore, present study was designed to evaluate selected essential and toxic trace metals (Ag, Ca, Mg, Na, K, Fe, Zn, Cu, Sr, Li, Co, Mn, Ni, Cr, Cd Pb and Zn) in the blood and scalp hair of newly diagnosed cancer patients suffering from head and neck cancers (including thyroid cancer, laryngeal cancer, nasopharyngeal cancer and lip & oral cavity cancer) in comparison with the matching healthy subjects. The samples were collected at Pakistan's Nuclear Oncology and Radiotherapy Institute (NORI), Islamabad, Pakistan. Flame atomic absorption spectrometry was used to determine the concentrations of the trace metals in each matrix using wet digestion procedure based on nitric acid and perchloric acid. The major contributors in the scalp hair of thyroid cancer patients were Ca (4194 µg/g), Mg (399.3 µg/g), Na (214.6 µg/g), and Zn (188.3 µg/g), whereas controls showed relatively higher levels of Ca (3218 µg/g), Mg (305.8 µg/g), Zn (170.9 µg/g), and Na (150.5 µg/g). Similarly, in the scalp hair of laryngeal cancer patients, comparatively higher levels were noted for Ca (1706 µg/g), Mg (225.9 µg/g), K (220.3 µg/g) and Zn, (205.6 µg/g) whereas for nasopharyngeal cancer patients, elevated mean levels were found for Ca (1,195 µg/g), Na (185.1 µg/g), Mg (161.9 µg/g), Zn (135.8 µg/g) and Fe (56.88 µg/g). Likewise, in the scalp hair of lip & oral cavity cancer patients, average concentrations of Ca (3515 µg/g), Zn (249.5 µg/g) Na (220 µg/g) and Mg (185 µg/g) were comparatively higher. However mean contents of Cr and Cu were significantly higher in the scalp hair of nasopharyngeal cancer patients, Pb and Fe levels were significantly higher in the scalp hair of laryngeal cancer patients. Strong correlation coefficients (r > 0.500) in the scalp hair of thyroid cancer patients were observed for Ag-Cr, Ca-Cu, K-Ca, Ca-Mg, Ni-Na, Ni-K, Ni-Mg, Pb-Cd, Pb-Co, Sr-Ca, Sr-K, and Sr Mg, whereas Ca-Mg and Na-K did so in the scalp hair of laryngeal cancer patients. The metals’ data were subjected to PCA & CA; they revealed significantly diverse apportionment of the metals in the scalp hair of various cancer patients compared to the controls. In the case of blood samples, thyroid cancer patients showed higher contributions for Na (1,318 µg/g), K (962.8 µg/g), Fe (282.6 µg/g), Ca (39.03 µg/g) and Mg (30.77 µg/g), while higher average levels in the blood of healthy donors were observed for Na (1284 µg/g), K (855.2 µg/g), Fe (252.8 µg/g), Ca (40.28 µg/g), Mg (28.06 µg/g) and Zn (15.77 µg/g). Likewise, mean levels of K (414.2 µg/g), Fe (369.9 µg/g), Na (219.4 µg/g), Ca (48.37 µg/g) xxii and Mg (27.92 µg/g) were predominantly higher in the blood of laryngeal cancer patients. On the average, concentrations of Fe, Cu, Sr, and Pb in the blood of laryngeal cancer patients were considerably higher than controls. Similarly, the mean contents of Co, K, Li, and Zn were significantly lower in the blood of nasopharyngeal cancer patients compared to the matching controls, whereas the mean concentrations of Ni, Fe, and Cu were significantly higher in the blood of lip & oral cavity cancer patients. Strong correlations were found between Fe-Ni, Zn-Cr, Ni-Cu, K-Ag, Mg-Li, Na-K, Cr-Na, Ni-Co, and Zn-Sr in the blood of thyroid cancer patients, as well as between Ag-Li, Cd-Cr, Cr-Cu, and Cu-Mn in the blood of lip and oral cavity cancer patients. Significant correlations were observed for Co-Cd, Li-Cd, and K-Co in the blood of nasopharyngeal cancer patients, while the correlation data for laryngeal cancer patients indicated strong relationships for Na-K, Sr-Na, Mn-K, and Cd-Na. PCA and CA revealed significantly divergent apportionment and multiple associations among the metals in the blood of various head and neck cancer patients compared with the controls. Average levels of selected metal in the blood and scalp hair of the patients and controls were compared based on age, gender, habitat, food habits, and smoking behaviours of the donors; significant disparities were observed in all categories. Considerable variations in the mean metal levels were found for various head and neck cancer patients with respect to the sub-types and stages of the cancer. The comparative study of the metal levels among the patients and the controls showed noticeably divergent variations. Additionally, the present metal concentrations in the scalp hair and blood of different types of cancer patients were compared to the reported metal levels from other regions around the world. Overall, the study revealed that the metal contents in the blood and scalp hair samples of the cancer patients exhibited considerable disparities related to the relative distribution, mutual associations and multivariate apportionment in comparison with the healthy subjects.