Consistency of prostate cancer grading results in screened populations across Europe

To assess the consistency of grading outcome among seven of eight participating centres of the European Randomised Screening Program of Prostate Cancer (ERSPC), a multicentre randomized trial intended to detect a difference in prostate cancer-related mortality between screened participants and a control group. Currently, tumour stage and grade in prostatectomy specimens represent the most predictive variables for biological behaviour. In prostate needle biopsies the tumour grade is a strong factor for deciding therapy.

Within the ERSPC all prostate cancers detected in needle biopsies were graded according to the Gleason score system. Gleason scores were compressed in three categories of < or = 6, 7 and 8-10. Data for grading outcome were obtained from the databases from seven individual centres; in one centre the slide sets with cancer were separately reviewed.

Combining the data of seven ERSPC centres 66% of cancers detected in the screening arm were Gleason score < or = 6 and 92% were < or = 7. Gleason score 8-10 cancers varied from 2 to 11%. This variation in Gleason scores may be attributed to differences in the population characteristics and biopsy indications.

These data indicate that in the seven ERSPC centres most screen-detected cancers have favourable characteristics on biopsy. Men with these cancers are amenable for treatment with curative intent. The observed differences in Gleason score distribution in different centres may partly be attributed to geographical differences and differences in the age range of the screened populations.