Diagnosis of high-grade prostate cancer in patients with unexpectedly low prostate specific antigen levels: a rare case series

Background: Prostate cancer is regarded as one of the most common leading causes of male cancer-related death worldwide. Clinicians agree that prostate specific antigen (PSA) is the best prostate cancer predictor. High PSA levels increase prostate cancer risk in most men. However, other research suggests that prostate cancer with low PSA levels is aggressive. In this uncommon case series, we present three high-grade prostate cancer patients with low PSA. Case Description: Between 2018 and 2019, three patients were referred for further therapeutic management after initial evaluation and treatment from secondary hospitals. All patients underwent complete diagnostic procedures including Laboratory examination, Pathological examination, and Radiologic imaging. PSA levels were 0.67 ng/mL, 4.0 ng/ml, and 4.93 ng/mL in the first, second, and third patients, respectively. The first two of three patients had a Gleason score (GS) of 9 (5+4), and one patient presented with GS of 8 (5+3). Distant metastatic disease was not found in our series. All of the patients underwent hormonal therapy, and none of them underwent radical prostatectomy. Follow-ups were completed in all patients, with the survival of 3 months, 4 months, and 12 months respectively. Conclusion: High-grade prostate cancer in patients with low PSA levels emphasizes the need for rigorous history taking and physical examination and quick investigation of new biomarkers and criteria for prostate cancer detection. These patients’ prognosis and optimal therapy are unknown. These patients have a worse prognosis than those with high PSA values, according to multiple studies.