This article is more than 5 years old. Information may no longer be current.
Finasteride linked to reduced prostate cancer risk, no effect on OS
Click Here to Manage Email Alerts
Finasteride reduced risk for prostate cancer by nearly a third, but it had no effect on survival of treated patients or those diagnosed with the disease, according to long-term follow-up to the Prostate Cancer Prevention Trial.
“Analyses [from the Prostate Cancer Prevention Trial] showed that the use of finasteride improved the sensitivity of PSA testing, prostate biopsy and digital rectal examination for the detection of prostate cancer, and improved the sensitivity of PSA testing and prostate biopsy for the detection of high-grade disease,” Ian M. Thompson Jr., MD, of the Cancer Research and Therapy Center at University of Texas Health Science Center, and colleagues wrote. “This improved sensitivity may be the result of a reduction in PSA levels in men receiving finasteride who have benign enlargement and subsequent shrinkage of the prostate.”
Ian M. Thompson Jr.
To determine the effect of finasteride on prostate cancer risk, Thompson and colleagues assessed survival rates from 18,882 men enrolled in the Prostate Cancer Prevention Trial.
In the original randomized controlled study, approximately half of the men enrolled were randomly assigned to receive either the 5-alpha-reductase inhibitor finasteride or placebo for 7 years. Data collection and cancer assessments were maintained for up to 10 years in most study participants.
According to study results, prostate cancer was diagnosed in 10.5% of men in the finasteride group and 14.9% of men in the placebo group (RR=0.7; P<.001). Thompson and colleagues detected high-grade disease in 3.5% of the men who received finasteride vs. 3% of men who received the placebo (RR=1.17; P=.05).
“Data from 18 years of follow-up showed that the use of finasteride over a period of 7 years in a general population of men with a median age at study entry of 63.2 years reduced the risk of prostate cancer but did not significantly affect mortality,” Thompson and colleagues wrote.
Researchers reported that 15-year survival rates were 78% for the finasteride group and 78.2% for the placebo group (unadjusted HR for death=1.02; P=.46).
For patients with low-grade prostate cancer, the researchers observed 10-year survival rates of 83% in the finasteride group and 80.9% in the placebo group, whereas 10-year survival rates for those with high-grade disease were 73% in the finasteride group and 73.6% in the placebo group.
“Although the prevention of these tumors did not appear to reduce overall mortality, increased diagnosis of low-grade prostate cancer is a problematic by-product of PSA testing, in that treatment adds little, if any, benefit and in that all forms of therapy cause considerable burden to the patient and to society,” Thompson and colleagues wrote.
Disclosure: Researchers report consulting relationships with Amgen, Eli Lilly and Ferring, as well as pending patent applications for a penile-prosthesis design and biomarkers for prostate-cancer detection.
Perspective
Back to Top
Karim Touijer
The Prostate Cancer Prevention Trial (PCPT) was initiated to determine if the 5-alpha-reductase inhibitor finasteride could reduce the risk for developing prostate cancer if administered to healthy men. Published in 2003, this large randomized, placebo-controlled study demonstrated that men randomly assigned to 7 years of finasteride had a lower risk for a low-grade cancer diagnosis, but an increased risk for a high-grade cancer diagnosis (Thompson IM. N Engl J Med. 2003;349:215-224). Subsequently, the use of finasteride in prostate cancer prevention was abandoned because of concerns of increased mortality secondary to induced development of high-grade tumors.
Thompson and colleagues recently presented long-term follow-up data from the PCPT, in addition to new survival data. Similar to the original report, men randomly assigned to finasteride had a 30% decreased risk for any prostate cancer diagnosis and a 43% decreased risk for a low-grade cancer diagnosis. High-grade cancers were diagnosed in 3.5% of men assigned to finasteride and 3% of men assigned to placebo (P=0.05). Interestingly, there was no increase in 15-year overall mortality among men assigned to finasteride, including those in whom prostate cancer was diagnosed. Therefore, men randomly assigned to 7 years of finasteride had a persistent reduction in the diagnosis of low-grade cancers without any increased mortality, despite the concern about a small rise in high-grade cancers.
This new data is highly relevant to the hotly debated issue of prostate cancer screening (Bangma CH. World J. Urol. 2007;25:3-9). The use of PSA to screen men for prostate cancer was found to be associated with a reduced risk for prostate cancer mortality. Its routine use, however, led to overdetection and treatment of indolent non life-threatening cancers, resulting in sexual and urinary dysfunctions. for men interested in prostate cancer screening, the new PCPT data show that the use of finasteride could potentially reduce the risk of overdiagnosis by decreasing the incidence of low grade cancers; and ease their concerns that finasteride induces the development of lethal cancers by demonstrating that the overall long-term survival rates are comparable between men who took finasteride and those who did not.
The PCPT findings reported by Thompson and colleagues are important to reignite interest in prostate cancer prevention with finasteride and perhaps tip the harm/benefit tradeoff of prostate cancer screening in a positive direction.
Click Here to Manage Email Alerts