Posted 6/18/2014 11:06 AM (GMT -6)
The use of Proscar or Avodart to treat prostate cancer is not a recognized label use for these products. In spite of this, they are used in hormone suppression protocols when maximal suppression is intended. Also used in intermittent androgen suppression during the off-cycle period to extend the time off medications. Drs. Leibowitz, Strum/Scholz and Bruchovsky have successfully used them to effectively extend the off-cycle period.
A study by Dr. Scolz concluded:” Finasteride doubles the duration of ADT3. AIPC was not increased by finasteride after almost 9 years of observation”.
Dr. William Fair studied the use of Proscar in treating stage D PCa and concluded that a decrease in serum PSA in the finasteride treatment group suggests that finasteride exerts a minor effect in patients with prostate cancer. This effect does not approach that seen with medical or surgical castration, but it is important because finasteride's lack of toxicity.
JE Damber and coworkers in Sweden showed that finasteride treatment decreases VEGF expression in the human prostate. Vascular endothelial growth factor (VEGF) is a potent regulatory factor of angiogenesis in human prostate tissue. Also Wang and coworkers at New York University demonstrated that the level of androgen receptor was dramatically decreased in the cells treated with finasteride.
In a recent prevention trial, Proscar reduced the incidence of PCa by 25%. It has been estimated that the use of Proscar would have a significant impact in PCa mortality. See reference by Thomsom I et al, below:
Fair WR et al.Multicenter, randomized, double-blind, placebo controlled study to investigate the effect of finasteride (MK-906) on stage D prostate cancer. J Urol 1992 Oct;148(4):1201-4
Damber JE et al. Effects of finasteride on vascular endothelial growth factor. Scand J Urol Nephrol 2002;36(3):182-7
Bruchovsky N et al Intermittent androgen suppression for prostate cancer: Canadian Prospective Trial and related observations. Mol Urol 2000 Fall;4(3):191-9;discussion 201
Wang LG et al Down-regulation of prostate-specific antigen expression by finasteride through inhibition of complex formation between androgen receptor and steroid receptor-binding consensus in the promoter of the PSA gene in LNCaP cells. Cancer Res 1997 Feb 15;57(4):714-9
Thompson IM Jr, LeBlanc M, Crowley JJ, Goodman PJ, Ford LG, Unger JM Coltman CA Jr. Estimated impact of the Prostate Cancer Prevention Trial on population mortality. Cancer. 2005 Apr 1;103(7):1375-80.
Scholz MC, Jennrich RI, Strum SB, Johnson HJ, Guess BW, Lam RY. Intermittent use of testosterone inactivating pharmaceuticals using finasteride prolongs the time off period. J Urol. 2006 May;175(5):1673-8. PubMed PMID: 16600727.
There is no question that these 5-AR inhibitors have a place in androgen deprivation. Dr. Klotz supports their use with active surveillance.