Effect of prostate volume on the predictive value of prostate-specific antigen density for prostate cancer.

Background: In clinical practice, we observed that some patients with larger prostate volume (PV) and prostate-specific antigen (PSA) values below 20 ng/mL still yielded negative biopsy results. We aim to establish a more precise volume range for guiding biopsies in patients with enlarged prostate glands.

Methods: We conducted a retrospective analysis of 424 cases involving patients who underwent prostate biopsy. The patients were categorized into three groups based on their body mass index: small (PV <45 cm), medium (45 cm≤ PV <70 cm), and large (PV ≥70 cm). Logistic regression, receiver operating characteristic (ROC) curves, restricted cubic spline (RCS) curves, and decision trees were employed for comparison purposes.

Results: In the multivariate logistic regression analysis, a statistically significant association was observed between prostate-specific antigen density (PSAD) ≥0.15 ng/mL/cm and the need for biopsy to confirm prostate cancer diagnosis when the volume was less than 45 cm [odds ratio (OR) =4.587; 95% confidence intervals (CI): 1.667-15.091; P=0.006]. The point of intersection between the RCS curve and the reference line occurred at PV =45 cm, indicating a higher risk of prostate cancer (PCa) increased with decreasing PV size. After constructing a decision tree model, it was found that when the volume was less than approximately 26 cm, there was a significantly increased probability (approximately 69%) of having prostate cancer after biopsy.

Conclusions: The likelihood of developing prostate cancer is higher in patients with small PVs (PV <45 cm), especially those with (PV <26 cm), when PSAD exceeds 0.15 ng/mL/cm. Patients with larger volumes (PV ≥70 cm) can be regularly monitored and followed up.