Alpha inhibitors and Prostate Cancer
For some time now there has existed some uncertainty about the role that 5 alpha reductase inhibitors (5ARis) may play in the development of prostate cancer. An earlier study had suggested that although reducing the risk of non-aggressive prostate cancers by around 30%, use of these agents might be responsible for a similar increase in the relative risk for the development of higher grade or more aggressive cancers.
A recent report published in Journal of the American Medical Association (JAMA) has looked into this issue. In the current study almost 39 000 men were prospectively followed up for a prostate cancer diagnosis and the their outcomes from this disease reported for a period between 1996 to 2010.
During this study there were 3681 incidents of prostate cancer, of which 289 were lethal, 456 high grade, 1238 were intermediate risk, and 1600 were low grade. High grade prostate cancer included Gleason 8-10 cancers, intermediate were Gleason 7 and the remaining low grade defined as Gleason less than or equal to 6.
A total of 2878 (7.6%) men reported use of 5ARIs during the study period. After adjusting for confounding factors:
-men who reported ever using 5ARIs over the study period had a reduced risk of overall prostate cancer.
-5ARI users had a reduced risk of intermediate and low-grade prostate cancer.
-5ARI use was not associated with risk of high-grade prostate cancer or lethal disease.
Increased duration of use was associated with significantly lower risk of overall prostate cancer, localized, and low-grade disease. There was no association for lethal, high-grade, or grade 7 disease. In summary the researchers of this trial concluded that 5Ari use did not increase the risk of higher grade or lethal prostate cancer. In addition it was associated with a reduction in Gleason 7 or less cancers.
A final caution was that because the number of patients with high-grade or lethal prostate cancer in this study was limited the authors could not exclude possible harm with 5ARI use.