Should we abstain from Gleason score 2-4 in the diagnosis of prostate cancer? Results of a German multicentre study.

Purpose: The present study analysed the loss of prognostic information related to the abandonment of Gleason score (GS) 2-4 by the International Society of Urological Pathology (ISUP-2005).

Methods: Within a 10-year period prior to the modification of GS, 856 patients (mean age 64.2 years) underwent radical prostatectomy (RP). The grade of agreement between GS in biopsy and definitive histology was calculated by Kappa statistics (κ). Univariable and multivariable influence of different preoperatively available parameters on disease-free survival (DFS) were assessed. The mean follow-up period was 39 months.

Results: Concordance between GS in biopsy versus RP samples was 58% (κ-value 0.354) and was improved by an increased number of biopsy cores. Undergrading in biopsy was present in 38% and not significantly enhanced by an extended time-period between biopsy and RP (threshold 90 d). PSA level, clinical tumour stage, fraction of positive cores (dichotomized at 34%), cases of RP per year and institution (dichotomized at 75), and GS independently influenced DFS. An upgrading to GS ≥ 7 was found in only 5.7% of patients presenting with GS 2-4 in the biopsy. Independent from definitive histology, patients with GS 2-4 had a significantly better prognosis compared to patients with a higher GS.

Conclusions: The present study shows an independent prognostic impact of GS in biopsy samples classified according to the previous classification. The elimination of GS 2-4 by the ISUP 2005 results in a considerable loss of pretherapeutic prognostic information and therefore should be questioned in particular with regard to the increasing demand for active surveillance regimens.