Population based study of predictors of adverse pathology among candidates for active surveillance with Gleason 6 prostate cancer

Purpose: Approximately a third of prostate cancer cases with a Gleason score of 6 are upgraded at radical prostatectomy. We studied trends and predictors of upgrading and up staging among men with Gleason 6 prostate cancer who were potential candidates for active surveillance in a population based cohort.

Materials and methods: From 2007 to 2011, 13,159 men were diagnosed with Gleason 6, clinical stage T1c/T2 prostate cancer in the NPCR (National Prostate Cancer Register of Sweden). Of these men 4,500 underwent radical prostatectomy, including 2,205 with data on the extent of prostate cancer in the biopsy cores. Logistic regression was used to examine variables associated with adverse pathology (defined as upgrading to Gleason 7 or greater, or up staging to pT3 or greater) in the full group and in potential candidates for active surveillance using 6 current published protocols.

Results: Among Swedish men with clinically localized Gleason 6 prostate cancer approximately 50% had adverse pathology at radical prostatectomy. Of the men who met the study inclusion criteria of 6 different active surveillance protocols, adverse pathology was present in 33% to 45%. Predictors of adverse pathology were older age, higher prostate specific antigen, prostate specific antigen density greater than 0.15 ng/ml/cm(3), palpable disease and extent of cancer greater than 4 mm on biopsy. Larger prostate volume had an inverse relationship with adverse pathology.

Conclusions: More than a third of men meeting the most stringent active surveillance criteria had adverse pathology at radical prostatectomy in this population based cohort. Active surveillance programs should consider prostate specific antigen density and extent of cancer on biopsy for patient selection.