Background: Prostate cancer is the second most common neoplasm and the fifth most aggressive cancer among men worldwide, with approximately 1.4 million new cases diagnosed annually. The incidence and mortality of prostate cancer increase with age, with a mean age at diagnosis of 66 years. Prostate cancer may be asymptomatic in its early stages and often has a latent period. The use of the Prostate-Specific Antigen (PSA) Index in the definitive diagnosis of prostate cancer remains a challenge for many urologists, and further research in this area can help to better understand the precise relationship between PSA levels and prostate cancer. Objectives: The present study aimed to investigate the relationship between PSA levels and prostate cancer in patients attending a urology clinic from 2014 to 2023, with the goal of improving diagnosis, developing effective treatments, and enhancing clinical outcomes. Methods: In this cross-sectional study, 242 patients with prostate cancer who attended a urology surgical clinic over a nine-year period from 2014 to 2023 were included. The patients were divided into two groups—youngest and oldest—based on the duration of their disease diagnosis. Demographic and clinical laboratory data were collected and entered into a checklist. Subsequently, the patients underwent a biopsy, and the results were recorded. Upon completion of the study, the collected data were entered into SPSS software for statistical analysis. Multiple regression analysis was used for correlation tests, while nonparametric tests, such as the Kruskal-Wallis test and the Mann-Whitney U test, were applied for nonparametric data analysis. Results: This study included 242 out of 276 samples for analysis. The ages of the participants ranged from 41 to 90 years, with a mean age of 67 ± 9.42 years. The data indicated that at PSA concentrations of 4 - 10 ng/mL, 5% of the samples were healthy, 15.2% had cancer, 46% had benign prostatic hyperplasia (BPH), and 33% had prostate intraepithelial neoplasia (PIN). At PSA concentrations of 10 - 50 ng/mL, 6% of the samples were healthy, 37% had cancer, 26% had BPH, and 29% had PIN. At PSA concentrations greater than 50 ng/mL, 3% of the samples were healthy, 76% had cancer, 14% had BPH, and 7% had PIN. A chi-square test revealed a significant association between PSA levels and pathological response (P < 0.001). Additionally, an analysis of variance (ANOVA) test showed a significant difference between different age and severity groups (P < 0.001). The free PSA-to-total PSA ratio in this study was 0.18, and the PSA-to-prostate volume ratio was 0.15, both of which were significantly associated with biopsy results (P < 0.01). Conclusions: Overall, the data obtained from this study indicated that plasma PSA levels were directly associated with the likelihood of prostate cancer. Additionally, the results showed that plasma PSA levels were not only directly associated with age but also correlated with the severity of trophic disorders, such as cancer, as indicated by biopsy results.