Differences in histopathological and biochemical outcomes in patients with low Gleason score prostate cancer.

Study Type: Diagnosis (case series).

Level Of Evidence: 4.

Objective: To test whether the number or percentage of positive biopsy cores can be used to discriminate between patients with prostate cancer of a favourable and less favourable Gleason score (GS) < or =3 + 3, as prognostically, not all GS 3 + 3 prostate cancers are the same.

Patients And Methods: In all, 1106 consecutive patients with a prostate-specific antigen (PSA) level of < or =10 ng/mL and a biopsy GS of < or =3 + 3 or 3 + 4 had an open radical prostatectomy. The number of positive biopsy cores (< or =2 vs > or =3) were stratified into low- vs high-risk groups. Subsequently, we stratified patients according to the GS and the percentage of positive biopsy cores (<50% vs > or =50%). The pathological stage and the 5-year biochemical recurrence (BCR)-free survival rates were examined in univariable and multivariable models.

Results: Based on the number of positive cores, the rate of extraprostatic disease was 11.7% and 23.3%, respectively, in the low-and high-risk GS < or =3 + 3 groups (P < 0.001). The 5-year BCR-free survival rates were 95.0%, 77.8%, 81.2% and 66.5% for, respectively, low- and high-risk GS < or =3 + 3 and for low- and high-risk GS 3 + 4 patients. Univariable and multivariable intergroup BCR rate differences were statistically significant between low- vs high-risk GS 3 + 3 patients (P < 0.001), but not significant between high-risk GS < or =3 + 3 vs low-risk GS 3 + 4 patients (P = 0.6). Comparable results were obtained when comparisons were made according to the percentage of positive biopsy cores.

Conclusions: Our results corroborate the finding that not all patients with a biopsy GS of < or =3 + 3 prostate cancer have low-risk disease. High-risk GS < or =3 + 3 patients have a similar risk profile as more favourable GS 3 + 4 patients. This finding warrants consideration when deciding on treatment.