Redefining the Concept of Clinically Insignificant Prostate Cancer

Area of Science:

• Urology
• Oncology
• Pathology

Background:

• Current criteria by Stamey and Epstein define small, low-grade prostate tumors after radical prostatectomy (RP) as clinically insignificant.
• However, the actual risk of biochemical recurrence (BCR) for these tumors requires further assessment.

Purpose of the Study:

• To evaluate the risk of BCR in small, low-grade prostate tumors following RP, challenging existing definitions of clinically insignificant prostate cancer.
• To redefine the concept of insignificant prostate cancer based on empirical data.

Main Methods:

• Analysis of pathological data from 3784 men who underwent RP between 1998 and 2019 with specific tumor characteristics (Gleason sum ≤6 or 3+4, prostate-confined, negative margins).
• Logistic regression modeling was used to analyze the risk of BCR based on tumor volume and Gleason pattern 4 percentage.
• Median follow-up was 96.8 months.

Main Results:

• Biochemical recurrence (BCR) occurred in 2.91% of patients (110 men).
• No significant difference in BCR rates was observed between tumor volumes <0.5 mL and 0.5-2.0 mL for Gleason 6 or Gleason 3+4 tumors.
• Tumor size >2 mL with ≥30% Gleason pattern 4 showed a significant increase in BCR.

Conclusions:

• The study does not support Stamey's or Epstein's criteria for defining insignificant prostate cancer based solely on tumor volume and Gleason score.
• All evaluated tumor groups exhibited some risk of BCR, indicating no truly "risk-free" cancer.
• The concept of "insignificant cancer" is proposed to be redefined as "low risk" cancer, encompassing smaller tumors with minimal Gleason pattern 4 components.