Purpose: Active surveillance of intermediate risk prostate cancer is controversial. Many active surveillance programs are limited to men with Grade Group 1 (Gleason 6) disease and prostate specific antigen less than 10 ng/ml. However, recent guidelines state that active surveillance can be considered in cases of limited Grade Group 2 (Gleason 3 + 4) despite limited data on outcomes. We compared prostatectomy outcomes between prostate cancer subgroups of intermediate risk vs low risk.
Materials and methods: We performed an observational study in the National Prostate Cancer Register of Sweden, which includes 98% of prostate cancer cases nationwide. From 2009 to 2012 radical prostatectomy was performed in 5,087 men with low risk prostate cancer (Grade Group 1, prostate specific antigen less than 10 ng/ml and cT2 or less) and intermediate risk prostate cancer (Grade Group 2, prostate specific antigen 10 to 20 ng/ml or T2). We compared upgrading and up staging between the groups based on the CAPRA (Cancer of the Prostate Risk Assessment) scores and published active surveillance criteria. Results were validated in an independent data set of cases diagnosed from 2013 to 2016.
Results: Men with Grade Group 1, prostate specific antigen 10 to 15 ng/ml and prostate specific antigen density less than 0.15 ng/ml/cm did not significantly differ in upgrading or adverse pathology findings compared to men with low risk prostate cancer. Prostate specific antigen greater than 15 ng/ml or Grade Group 2 was associated with a significantly greater risk of aggressive prostate cancer. Men with low risk CAPRA scores (0 to 2) and Grade Group 2 disease were at almost threefold increased risk of upgrading and twofold increased risk of adverse pathology compared to men with low risk CAPRA, Grade Group 1 disease.
Conclusions: Expanding the prostate specific antigen threshold to 15 ng/ml for Grade Group 1 prostate cancer would allow more men to elect active surveillance. This is unlikely to compromise outcomes, particularly if prostate specific antigen density is low. In contrast, caution should be exercised in offering active surveillance to men with prostate specific antigen greater than 15 ng/ml or Grade Group 2 prostate cancer.