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Keywords:

  • prostate cancer;
  • active surveillance;
  • positive cores;
  • spatial distribution;
  • prostate biopsy

Objective

  • To test the hypothesis that spatial distribution of positive cores at biopsy is a predictor of unfavourable prostate cancer characteristics at radical prostatectomy (RP) in active surveillance (AS) candidates.

Patients and Methods

  • We examined the data of 524 patients treated with RP, between 2000 and 2012. All fulfilled at least one of four commonly used AS criteria.
  • Regression models tested the relationship between positive cores spatial distribution, defined as the number of positive zones at biopsy (PBxZ) and tumour laterality at biopsy and two endpoints: (i) unfavourable prostate cancer at RP (Gleason score ≥4 + 3, and/or pT3 disease), and (ii) clinically significant prostate cancer (tumour volume ≥2.5 mL).

Results

  • Unfavourable prostate cancer and clinically significant prostate cancer rates were 8 and 25%, respectively. Patients with more than one PBxZ had a 3.2-fold higher risk of harbouring unfavourable prostate cancer, and a 2.3-fold higher risk of harbouring clinically significant prostate cancer compared with their counterparts with one PBxZ (both P = 0.01).
  • Patients with bilateral tumour at biopsy had a 3.3-fold higher risk of harbouring unfavourable prostate cancer and a 1.7-fold higher risk of harbouring clinically significant prostate cancer compared with their counterparts with unilateral tumour at biopsy (both P ≤ 0.04).
  • Some of these results did not reach a statistically significant level, when the analyses were restricted to patients that fulfilled the most stringent AS criteria.

Conclusions

  • Positive cores spatial distribution at biopsy should be considered, when advising patients about AS.
  • The addition of this predictor to AS inclusion criteria can help identifying patients at a higher risk of progression, and reduce the rate of inappropriate surveillance of aggressive tumours. However, the most stringent AS criteria (namely John-Hopkins criteria and Prostate Cancer Research International: Active Surveillance criteria) might not benefit from the addition of this predictor. This point warrants further investigation in future studies.