Dutasteride effective adjunct to active surveillance in prostate cancer
MedWire News: The 5a-reductase inhibitor dutasteride is a beneficial adjunct to active surveillance for men with low-risk prostate cancer, show study findings.
"The results prove that using active surveillance plus dutasteride is a viable, safe, and effective treatment option for men who often undergo aggressive local treatment despite low risk of dying from the disease," said lead author Neil Fleshner (University of Toronto, Ontario, Canada) in a press statement.
"The 5a-reductase inhibitors block the conversion of testosterone to dihydrotestosterone, leading to a reduction in prostate volume and a decrease in prostate-specific antigen (PSA)," explain Fleshner and team in The Lancet.
The researchers conducted the Reduction by Dutasteride of Clinical Progression Events in Expectant Management (REDEEM) trial to assess the efficacy and safety of dutasteride in extending time to prostate cancer progression in 302 men with low-risk (T1c-T2a prostate cancer stage and Gleason score of 6 or less), localized disease.
All the men were under "active surveillance" including regular prostate examination, prostate-specific antigen (PSA) measurement, and repeat biopsies, and half were randomly allocated to receive dutasteride 0.5 mg and half to receive matching placebo (control group) once daily for 3 years.
The team measured the patients' PSA levels during follow-up visits, which occurred every 3 months for the first year and every 6 months for the remainder of the study. All participants underwent 12-core transrectal ultrasound-guided prostate biopsy sampling at 18 months, and at 3 years.
Anxiety related to prostate cancer was also assessed using the memorial anxiety scale for prostate cancer (MAX-PC questionnaire), which measures three aspects of cancer-related anxiety: general anxiety, fear of recurrence, and anxiety specifically related to PSA testing.
The researchers report that dutasteride significantly delayed prostate cancer progression compared with placebo during the follow up.
At 18 months, prostate cancer had progressed in significantly fewer in the dutasteride group than in the control group, at 32 (23%) versus 50 (35%), respectively.
And by 3 years, the cancer had progressed in only 54 (38%) of the men in the dutasteride group compared with 70 (48%) in the control group.
Of the men who had a Gleason score of more than 6 by the final biopsy sampling (19 in the dutasteride group, 22 controls), the authors noted a shorter tumor length and a lower percentage of positive cores in men treated with dutasteride than in those who were treated with placebo.
Furthermore, they found that the men receiving dutasteride reported significantly lower overall anxiety than those receiving placebo did.
"This reduction in anxiety seemed to be driven by a reduction in fear of prostate cancer recurrence, in which the dutasteride group had significant reductions compared with the placebo group from 12 months onwards," they report.
The team also says there were no significant differences in drug-related adverse events between the two groups.
"We believe that future studies of medical therapies for men on active surveillance should use dutasteride as the comparator," they conclude.
By Sally Robertson