Results
In total, we identified 197 patients with a proven pathology of prostate
adenocarcinoma and 274 male controls between January 2016 and April
2020. After excluding other cancer cases or cases without individual
matches, 180 patients and 240 controls were included in our study. Table
1 related to the summary of participant characteristics shows the only
significant difference between controls and cases was the PSA levels (p
<0.001). Most of the study participants were 65 years above
(75.2%), married (87.7%), most of them had college or high school
degrees (76.7%), were nonsmokers (70.1%), took no vitamin D
supplements (96.6%) and had no history of prostate cancer in the family
(85.5%). Only a minority used alcohol (11.2%). The two groups had no
statistically significant difference in terms of these characteristics
(p: 0.64). When compared to the control group, significantly lower
urinary melatonin sulfate levels (49.85 ± 46.58 vs. 64.25 ± 66.75 ng/mg
creatinine, p = 0.003) and lower M/C ratios (2.38 ± 3.20 vs. 5.28 ±
15.32, p <0.001, respectively) were detected in the patients.
However, there were significantly higher mean levels of urinary cortisol
in the cases had than those in the controls (33.12 ± 29.42 vs. 26.65 ±
20.85 ng/mg creatinine, p = 0.007, respectively).
After other common variables were adjusted, we discovered that subjects
who had a high M/C ratios or urinary melatonin-sulfate level were
significantly less exposed to prostate cancer than those who had a low
M/C ratios and urinary melatonin-sulfate level (aOR = 0.45, and 95% CI
= 0.31–0.81; and adjusted OR [aOR] = 0.61, and 95% CI =
0.34–0.98, respectively) (Table 2). In addition, we discovered that
subjects with both a low M/C ratio and preoperative PSA levels above 10
ng/mL were 3.58 times more likely (95% CI = 1.58–8.12) to develop
prostate cancer compared to those with a high M/C ratio and preoperative
low PSA (<10 ng/mL) (Table 2). The group with low preoperative
PSA levels and M/C ratios exceeding 10 ng/mL (aOR = 8.79; 95% CI =
4.01–18.97) was exposed to higher risks. When the risk of melatonin
sulfate or cortisol and PSA level was combined, the subjects l showed a
similar risk pattern. While prostate cancer was categorized according to
the clinical stage i.e. advanced and localized, we discovered some
statistically significant differences in urine biomarkers during the
comparison of the advanced (end-stage) cancer group and the control
group. The M/C ratio and PSA level A did not yield multiplicative scale
of interaction (Table 3). Furthermore, we found that the advanced
(end-stage) cancer group had combined effect of a lower preoperative PSA
levels and M/C ratio exceeding 10 ng/mL than the localized cancer group
or control group (Table 3). When evaluating melatonin sulfate, cortisol,
and PSA levels in combination, the subjects had a similar trend pattern.