Tumor characteristics, treatments, and survival outcomes in prostate cancer patients with a PSA level < 4 ng/ml: a population-based study

BACKGROUND: To examine the tumor characteristics, treatments and survival outcomes of prostate cancer (PCa) patients with a prostate-specific antigen (PSA) level < 4 ng/ml. METHODS: Of 205,913 men with primary prostate adenocarcinoma in the Surveillance, Epidemiology and End Results (SEER) database (2010 to 2015), 24,054 (11.68%) patients were diagnosed with a PSA level < 4 ng/ml. Comparisons of categorical variables among different groups were performed by using the Chi square test. Multivariate Cox regression analysis was adjusted for age, ethnicity, marital status, insurance status, TNM stage, Gleason grade, treatment and survival. Kaplan-Meier survival curves were constructed for overall mortality and tested by the log-rank test. RESULTS: PCa patients with a PSA level < 4 ng/ml generally had more favorable tumor characteristics: younger, lower T stage, lower Gleason grade and lower lymph node metastasis rate. However, there were more patients in stage M1 in the group of PSA level < 4 ng/ml than that in the groups of PSA level of 4–10 ng/ml, 10–20 ng/ml and > 20 ng/ml. The multivariate Cox regression model revealed that overall mortality was associated with age, marital status, race, Gleason grade, M stage and treatment approach. CONCLUSIONS: In conclusion, PCa patients with a PSA level < 4 ng/ml have more favorable tumor characteristics at diagnosis and receive more benefit from active treatment. However, those patients with advanced TNM stage and high Gleason grade should be paid more attention in clinical application.