Quick Poll results from the of OncoFacts 2010

Your brother-in-law calls for your advice. He is 55 years old and recently had his first prostate-specific antigen (PSA) screening test. His PSA level was 3.1 and a repeat level 1 month later was 3.0. His urologist recommended a transrectal ultrasound (TRUS) guided biopsy. Twelve cores were taken and all were negative for prostate cancer. He reminds you that his father was diagnosed with prostate cancer at age 70, but died 5 years later of heart disease. He called to ask if he should take the 5-alpha-reductase inhibitor recommended by his urologist to reduce his risk of prostate cancer. What would you recommend?

Discussion

The SELECT trial was a randomized, placebo controlled trial involving 35, 533 men comparing selenium vs vitamin E vs selenium + vitamin E vs placebo. With a median follow-up of 5.5 years, there was no evidence that vitamin E, selenium, or the combination prevented prostate cancer in the large population of healthy men participating in the study.
Two trials have now been published comparing placebo with a 5-alpha-reductase inhibitor (5ARI) in men at increased risk of prostate cancer. The PCPT compared finasteride with placebo and the REDUCE trial compared dutasteride with placebo. Both trials demonstrated a 23% - 25% reduction in the occurrence of prostate cancer in the 5ARI groups compared to the placebo group.

There was some concern in the PCPT trial regarding an increased incidence of high-grade prostate cancer in the 5ARI group taking finasteride, but many experts feel it is unlikely that there is a causative relationship. The incidences of high grade (GS = 8 to 10) in the REDUCE trial were essentially the same in the 5ARI group and the placebo group.
In addition, in the REDUCE trial there was a marked reduction in the incidence of acute urinary retention, BPH-related surgery, and urinary tract infections in the group taking dutasteride.

Adverse events with both agents include decreased libido, erectile dysfunction, decreased semen volume, and gynecomastia, but most of these adverse events occurred in less than 5% of trial participants and often improved with time. There was a slight increased incidence of cardiac events in the group receiving dutasteride in the REDUCE trial.
The authors of the REDUCE trial concluded that “dutasteride may be considered as a treatment option for men who are at increased risk for prostate cancer”.

However, in an accompanying editorial, Patrick Walsh from Johns Hopkins, seems unconvinced and stated “Dutasteride and finasteride do not prevent prostate cancer but merely temporarily shrink tumors that have low potential for being lethal, and they do not reduce the risk of a positive biopsy in patients who have an elevated PSA level or an abnormal digital rectal examination.” He also expressed concern that men on 5ARIs would develop a false sense of security from the 50% reduction in PSA levels expected with the use of 5ARIs.

References
1. Thompson IM, Goodman PJ, Tangen CM, et al. The influence of finasteride on the development of prostate cancer. N Engl J Med. 2003;349(3):215-224.
2. Cohen YC, Liu KS, Heyden NL, et al. Detection bias due to the effect of finasteride on prostate volume: a modeling approach for analysis of the Prostate Cancer Prevention Trial. J Natl Cancer Inst. 2007;99(18):1366-1374.
3. Lippman SM, Klein EA, Goodman PJ, et al. Effect of selenium and vitamin E on risk of prostate cancer and other cancers: the Selenium and Vitamin E Cancer Prevention Trial (SELECT). JAMA. 2009;301(1):39-51.
4. Andriole GL, Bostwick DG, Brawley OW, et al. Effect of dutasteride on the risk of prostate cancer. N Engl J Med. 2010;362(13):1192-1202.
5. Walsh PC. Chemoprevention of prostate cancer. N Engl J Med. 2010;362(13):1237-1238.

 

 

* The aggregate results from this question were compiled from the responses submitted by oncologists who participated in the OncoFacts Quick Poll monthly question.