Magnetic resonance imaging does not improve the prediction of misclassification of prostate cancer patients eligible for active surveillance when the most stringent selection criteria are based on the saturation biopsy scheme

Abstract

Study Type - Diagnostic (case series).

Level of evidence: 4.

Objective: • To investigate the role of magnetic resonance imaging (MRI) in selecting patients for active surveillance (AS).

Patients and methods: • We identified prostate cancers patients who had undergone a 21-core biopsy scheme and fulfilled the criteria as follows: prostate-specific antigen (PSA) level ≤ 10 ng/mL, T1-T2a disease, a Gleason score ≤ 6, <3 positive cores and tumour length per core <3 mm. • We included 96 patients who underwent a radical prostatectomy (RP) and a prostate MRI before surgery. • The main end point of the study was the unfavourable disease features at RP, with or without the use of MRI as AS inclusion criterion.

Results: • Mean age and mean PSA were 62.4 years and 6.1 ng/mL, respectively. Prostate cancer was staged pT3 in 17.7% of cases. • The rate of unfavourable disease (pT3-4 and/or Gleason score ≥ 4 + 3) was 24.0%. A T3 disease on MRI was noted in 28 men (29.2%). MRI was not a significant predictor of pT3 disease in RP specimens (P = 0.980), rate of unfavourable disease (P = 0.604), positive surgical margins (P = 0.750) or Gleason upgrading (P = 0.314). • In a logistic regression model, no preoperative parameter was an independent predictor of unfavourable disease in the RP specimen. • After a mean follow-up of 29 months, the recurrence-free survival (RFS) was statistically equivalent between men with T3 on MRI and those with T1-T2 disease (P = 0.853).

Conclusion: • The results of the present study emphasize that, when the selection of patients for AS is based on an extended 21-core biopsy scheme, and uses the most stringent inclusion criteria, MRI does not improve the prediction of high-risk and/or non organ-confined disease in a RP specimen.