Aiming at finding the most relevant articles for this review, a thorough comprehensive web search was conducted by consulting the PubMed, Scopus, ELSEVIER-EMBASE, Cochrane Library, and the Web of Science databases, as well as from the personal archive of the author collected between 1966 to 2020, using the key words: prostatic trace elements, prostatic Sb content, prostatic tissue, and their combinations. For example, the search terms for Sb content were: Sb mass fraction , Sb content , Sb level , prostatic tissue Sb and Sb of prostatic tissue . The language of the article was not restricted. The titles from the search results were evaluated closely and determined to be acceptable for potential inclusion criteria. Also, references from the selected articles were examined as further search tools. Relevant studies noted for the each selected article were also evaluated for inclusion.

A standard extraction of data was applied, and the following available variables were extracted from each paper: method of Sb determination, number and ages of healthy persons, sample preparation, mean and median of Sb levels, standard deviations of mean, and range of Sb levels. Abstracts and complete articles were reviewed independently, and if the results were different, the texts were checked once again until the differences were resolved.

Studies were combined based on means of Sb levels in prostatic tissue. The articles were analyzed and Median of Means and Range of Means were used to examine heterogeneity of Sb contents. The objective analysis was performed on data from the 23 studies, with 1173 subjects

Information about Sb levels in prostatic tissue in different prostatic diseases is of obvious interest, not only to understand the etiology and pathogenesis of prostatic diseases more profoundly, but also for their diagnosis, particularly for PCa diagnosis and PCa risk prognosis 2736. Thus, it dictates a need for reliable values of the Sb levels in the prostatic tissue of apparently healthy subjects, ranging from young adult males to elderly persons.

Possible publications relevant to the keywords were retrieved and screened. A total of 1998 publications were primarily obtained, of which 1975 irrelevant papers were excluded. Thus, 23 studies were ultimately selected according to eligibility criteria that investigated Sb levels in tissue of normal prostates (Table 1) and these 23 papers 79111314242628404142434445464748495051525354 comprised the material on which the review was based.

A number of values for Sb mass fractions were not expressed on a wet mass basis by the authors of the cited references. However, we calculated these values using the medians of published data for water – 83% 55565758 and ash – 1% (on a wet mass basis) contents in normal prostates of adult men 57596061.

(Table 1) summarizes general data from the 23 studies. The retrieved studies involved 1173 subjects. The ages of subjects were available for 20 studies and ranged from 0–87 years. Information about the analytical method and sample preparation used was available for 22 studies. One study determined Sb levels by inductively coupled plasma mass spectrometry (ICPMS) (Table 1). ICPMS is the destructive analytical method, because it requires sample acid digestion. Nine studies detected Sb level in intact prostatic tissue samples by nondestructive analytical method, such as neutron activation analysis (NAA). In twelve studies a combination of destructive and nondestructive methods (ICPMS and NAA) was used and results were summarized.

(Figure 1) illustrates the data set of Sb measurements in 23 studies during the period from 1962 to 2020.

The range of means of Sb mass fractions reported in the literature for normal prostatic tissue varies widely from 0.0066 mg/kg 45 to <2.9 mg/kg 40 with median of means 0.0085 mg/kg wet tissue (Table 1). The maximal value of mean Sb mass fraction reported 40 was 341 times higher the median of Sb mass fraction means and at least one order of magnitude higher than all other published means. Thus, value <2.9 mg/kg 40 can be excluded. However, without this result range of means of Sb mass fractions for normal prostatic tissue remains very wide from 0.0066 mg/kg 45 to 0.071 mg/kg 28 with median of means 0.0085 mg/kg wet tissue and M_max/M_min ratio approximately 11 (Table 1).

This variability of reported mean values can be explained a priori by a dependence of Sb content on many factors, including analytical method imperfections, differences in normal prostate definitions, possible non-homogeneous distribution of Sb levels throughout the prostate gland volume, age, ethnicity, diet, smoking, alcohol intake, consuming supplemental trace elements, and others. Not all these factors were strictly controlled in the cited studies. For example, in some studies the normal prostate means a gland of an apparently healthy man who had died suddenly, but without any morphological confirmation of normality of his prostatic tissue. In other studies the normal prostate means a non-cancerous prostate (but hyperplastic and inflamed glands were included) and even a visually normal prostatic tissue adjacent to a prostatic malignant tumor. Some researchers used as the normal prostate the glands of patients who died from acute and chronic non-prostatic diseases including subjects who had suffered from prolonged wasting illnesses. In some studies whole glands were used for the investigation while in others the Sb content was measured in pieces of the prostate. Therefore published data allowed us to estimate the effect of only some different factors on Sb content in normal prostate tissue.