Giving 5-alpha reductase inhibitors (5-ARIs) to men with low-risk prostate cancer undergoing active surveillance was associated with a lower rate of pathologic progression in a small retrospective cohort study. Men on 5-ARIs also had a longer median time to disease progression and were less likely to abandon active surveillance for active treatment.

A total of 288 men, mean age 64 years, on active surveillance for low-risk prostate cancer at a hospital in Ontario, Canada were followed up for a median of 38.5 months. Seventy of these patients were started on a 5-ARI at some point after their diagnostic biopsy.

Overall 93 men (32%) experienced pathologic progression (i.e. increased Gleason score or tumour volume on repeat biopsy); 13 (18.6%) in the 5-ARI group compared with 80 (36.7%) in the non-5-ARI group, p=0.004.

Furthermore, men on a 5-ARI experienced a longer median time to disease progression, 41.3 months, compared with those not taking the drug, 35.1 months, p=0.013.

With respect to progression to active treatment, 14 men (20%) on a 5-ARI abandoned active surveillance compared with 82 men (37.6%), p=0.006, in the other group. Median time to active treatment was significantly longer for the group on a 5-ARI, 42.5 months, compared with those not receiving a 5-ARI, 31.5 months, p=0.026.

Clearly this study has limitations, in terms of a retrospective design with small numbers, but it paves the way for the REDEEM study, a large randomised controlled trial on the use of dutasteride in this setting.

Dr Jonathan Rees