Men who undergo radical prostatectomy are often prescribed phosphodiesterase type 5 (PDE5) inhibitors to treat erectile dysfunction (ED) after surgery. However, a team of German scientists recently found an association between PDE5 inhibitor use and biochemical recurrence of prostate cancer in this population.
The finding was unexpected and contrasted with past research that showed a decreased incidence of prostate cancer among men who used PDE5 inhibitors.
It has been suggested that PDE5 inhibitors might slow down tumor growth and metastasis in prostate cancer patients. This study aimed to provide clinical data.
The researchers collected information from 4,752 patients with localized prostate cancer. All of the men had a bilateral nerve-sparing radical prostatectomy between January 2000 and December 2010. About 23% of the men took a PDE5 inhibitor (sildenafil, vardenafil, or tadalafil) after surgery. The rest did not.
The median follow up period was 60 months. Biochemical recurrence was defined as a PSA 0.2 ng/mL that increased after surgery.
For the men who did not take a PDE5 inhibitor, the estimated 5-year biochemical-recurrence-free survival rate was 89.2%. But for the men who did use a PDE5 inhibitor, the rate was 84.7%.
Age, body mass index, and smoking status did not seem to affect these results.
The researchers also performed a propensity score based match analysis with 1,102 pairs of men, but the rate for those who used PDE5 inhibitors was still significantly lower compared to those who did not take the drug.
The study authors noted that, to their knowledge, they were the first to find such results. “Therefore, an explanation of this finding is difficult and can only be speculative at present,” they wrote.
It’s possible that the effects of PDE5 inhibitors on the immune system, autonomic nerve development, or angiogenesis could be involved.
The authors noted that the study had several limitations, including its retrospective design and the fact that all men were treated at the same facility.
Also, the researchers did not know the type or dose of the drug used; nor did they know how frequently the drugs were taken and for what length of time.
“Therefore, our results need to be interpreted with caution,” they wrote, calling for additional research.
“This issue is of special clinical interest given the wide use of [PDE5 inhibitors] after radical prostatectomy and could potentially lead to revisiting the current recommendations,” they added.
The study was published online last September in The Journal of Urology.
The Journal of Urology
Michl, Uwe, et al.
“Use of Phosphodiesterase Type 5 Inhibitors May Adversely Impact Biochemical Recurrence after Radical Prostatectomy”
(Full-text. Published online: September 5, 2014)
“Docs 'Astonished': ED Drugs Tied to Prostate Cancer Return”
(January 27, 2015)
Renal and Urology News
Charnow, Jody A.
“Erectile Dysfunction Drugs May Worsen Prostate Cancer Surgery Outcomes”
(January 29, 2015)