Profile of Tissue Selenium Concentration In A Cohort Of Nigerian Men With Prostate Cancer
Author(s): Igbokwe MC, Badmus TA, Salako AA, Obiajunwa EI, Olasehinde O, Igbokwe CA, David RA
Introduction: The global burden of prostate cancer (CaP) has led to increasing research into the aetiological factors and preventive measures for the disease. The role of Selenium (Se) has recently been the focus of several research efforts. Its influence on development of prostate cancer is however still controversial.
Objectives: The aim of this study was to determine the relationship between tissue selenium levels and the occurrence of prostate cancer among men in Ile-Ife, Nigeria.
Methodology: This was a prospective hospital-based comparative study carried out in the Urology unit of the Obafemi Awolowo University Teaching Hospital Complex, Ile Ife, over a period of one year. Consecutive consenting men with histologically confirmed prostate cancer alongside age-matched controls were recruited for this study. These participants had whole blood and toe-nail samples collected for selenium assay using the Particle induced X-ray emission (PIXE) technique. The patients with prostate cancer had same samples collected 1 month after orchidectomy to reassess the selenium levels.
Data Analysis: The data was entered and analysed using the IBM Statistical Package for Social Sciences (SPSS) Statistical Software for Windows, Version 20. Univariate analysis was utilized to determine the sociodemographic data of the subjects, using percentages and means (with standard deviation). The independent T-test was employed to determine if there was any significant difference in the whole blood and toe-nail selenium between the study and control groups while the paired T-test was used to compare the pre and post-orchidectomy tissue selenium concentrations using a significance level of 0.05 at 95% confidence interval.
Results: Forty-one patients with CaP were recruited with equal number of age-matched controls for this research. The mean age of CaP patients was 72.83± 7.06 years which was comparable to age of controls (p= 0.12). The median whole blood selenium concentration among Prostate Cancer group was 67.00 ng/ml with an inter-quartile range of 52.50 which was much lower than in the control group which was 132.00 ng/ml and inter-quartile range of 83.00. This difference was statistically significant (p=0.002). A similar pattern was observed with the toe-nail selenium concentration with Prostate cancer patients having significantly lower Selenium levels than controls with median values of 11.85 ng/ml and 67.00 ng/ml respectively (p=0.001). Overall, this study observed that selenium levels in whole blood were higher than in toe-nail in both patients and controls (p=0.02 and p= 0.03 respectively). Amongst patients with CaP Se levels were noted to be lowest in patients with more severe disease as depicted by higher PSA results and worse Gleason scores. Following bilateral total orchidectomy, there was a marginal, non-statistically significant increase in both whole blood and toe-nail selenium concentration at 1 month follow up (p=0.16, p=0.47 respectively).
Conclusion: Patients with CaP had much lower Se levels compared to controls in the study population. Only a marginal non-statistically significant increase was however observed in the Selenium levels following bilateral total orchidectomy at 1 month follow up.