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

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.

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 cm³), medium (45 cm³≤ PV <70 cm³), and large (PV ≥70 cm³). Logistic regression, receiver operating characteristic (ROC) curves, restricted cubic spline (RCS) curves, and decision trees were employed for comparison purposes.

In the multivariate logistic regression analysis, a statistically significant association was observed between prostate-specific antigen density (PSAD) ≥0.15 ng/mL/cm³ and the need for biopsy to confirm prostate cancer diagnosis when the volume was less than 45 cm³ [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 cm³, 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 cm³, there was a significantly increased probability (approximately 69%) of having prostate cancer after biopsy.

The likelihood of developing prostate cancer is higher in patients with small PVs (PV <45 cm³), especially those with (PV <26 cm³), when PSAD exceeds 0.15 ng/mL/cm³. Patients with larger volumes (PV ≥70 cm³) can be regularly monitored and followed up.