Olusegun Isaac Alatise

BACKGROUND The aim of this study is to describe the trends and variations in the global burden of colorectal cancer (CRC). METHODS Data (2012‐2030) relating to CRC was extracted from GLOBOCAN 2012 database and analyzed. RESULTS The results of our study demonstrate a rising global burden of colorectal cancer which persists until the year 2035 and likely beyond. The rise in the global burden is not uniform with significant variations influenced by geographic location, socio‐economic status, age, and gender. Although the EURO region has the highest burden, Asia as a continent continues to bear the heaviest brunt of the disease. Although the burden of disease is higher in more developed regions, mortality is considerably higher in less developed regions and this gap widens over the next two decades. The disease predominantly affects the male gender across all regions of the world. Age has a complex relation with the burden of CRC and is affected by the cross‐influences relating to socio‐economic status. CONCLUSIONS The results of our study demonstrate a rising global burden of CRC with some unique variations. Knowledge of this data can increase awareness and help strategic targeting of efforts and resources.

Breast cancer incidence in Nigerian women has significantly increased during the past three decades in parallel with the rapid industrialization of that country. This suggested that the associated widespread contamination of the soil and of the water supplies by lead (Pb) and other industrial metals was a major contributing cause. Because of its many domestic, industrial, and automotive uses, Pb is of particular concern as it has been shown to promote the development of mammary tumors in murine mammary tumor virus-infected female C3H mice at levels as low of 0.5 ppm Pb in the drinking water. Lead belongs to the group of selenium-antagonistic elements that interact with selenium (Se), abolishing its anti-carcinogenic effect. Lead on chronic, low-level exposure in addition also accelerates tumor growth rates. Higher levels of Pb were found in blood and head hair samples of newly diagnosed patients with breast cancer, all with infiltrating ductal carcinoma, the most common form of breast cancer in Nigeria, seen at Obafemi Awolowo University, than in cancer-free controls from the same area. Evidence for interactions between Pb and Se was obtained from blood, hair, and tumor biopsy tissue analyses. Furthermore, the Pb levels in hair samples of the patients were directly correlated with the volumes of their tumors, in accord with the tumor growth-promoting effects of Pb. Conversely, Se levels in hair and blood were inversely correlated with the tumor volumes, consistent with the anti-proliferative effects of Se. Several other elements, e.g., Cd, Hg, Cr, Sn, and As, were detected in the scalp hair of the patients and the controls, although at significantly lower levels than those of Pb. However, correlation calculations revealed them also to interact with Se, suggesting that only a fraction of the Se in organs and tissues is actually present in bioactive forms. In metal-exposed subjects, a state of latent Se deficiency may exist, resulting in depressed immune functions and increased cancer susceptibility. Evidence is presented to show that Pb and other metals also interact with iodine, another vitally important essential trace element believed to protect against breast cancer development. Public health programs aiming at lowering the breast cancer risk of Nigerian women thus will have to include effective measures to protect the population from exposures to Pb and other industrial metals that are presently contaminating the environment and the water supplies.