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.