Selenium levels of patients with newly diagnosed prostate cancer compared with control group

To compare the toenail selenium level of patients with prostate cancer with that of controls. A tumor-protective effect of selenium has been discussed for many years. Published data about the influence of the selenium level in the plasma and toenails are controversial.

Our prospective study included 150 patients. Of these, 70 patients had recently diagnosed prostate cancer (cancer group) and 80 patients had no evidence of prostate cancer (negative digital rectal examination and prostate-specific antigen level within age-specific range or negative biopsies) or any other malignant disease (control group). Toenail clippings exhibit selenium levels for up to 1 year. Both groups were compared by assessing their selenium levels using inductively coupled plasma dynamic reaction cell mass spectrometry after microwave-assisted closed vessel digestion. The results of the selenium levels in both groups were statistically compared using the Wilcoxon test. Possible correlations between the selenium level and age, body mass index, smoking habits, and prostate cancer were analyzed by multiple regression analysis.

The median age of the cancer and control group was 65 and 69 years, respectively. The median toenail selenium level in the cancer and control group was 528 ng/g (range 393 to 4274) and 502 ng/g (range 201 to 831), respectively (P value not statistically significant). Furthermore, no correlation was found between selenium level and age, body mass index, or smoking status.

The patients in our study with newly diagnosed and not yet treated prostate cancer did not have different toenail selenium levels than controls. Body selenium levels may not influence prostate cancer incidence. A protective effect of selenium for prostate cancer seems questionable.