Prostate Cancer and Finasteride

Introduction to Finasteride and Prostate Cancer

Finasteride, a 5α-reductase inhibitor, is used for the treatment of hair loss and has been shown to decrease the period prevalence of prostate cancer by approximately 26%, as recommended by the American Urological Association 1
The Prostate Cancer Prevention Trial (PCPT) demonstrated a reduction in prostate cancer risk with finasteride administration for 7 years 2

Finasteride significantly reduces PSA levels, requiring adjustment when interpreting PSA results for prostate cancer screening, with a recommended multiplier of approximately 2x for men over 50 3, 2
The American Urological Association provides guidelines for prostate cancer screening, including consideration of baseline and periodic PSA testing for men over 50 2

5α-reductase inhibitors, such as finasteride, are associated with several sexual side effects, including erectile dysfunction (ED), decreased libido, and ejaculatory disorders, which occur at higher rates than placebo, with a relative risk of 1.71 for ED, 1.83 for decreased libido, and 1.75 for ejaculatory disorders compared to placebo 1, 2
Regular assessment of sexual function is recommended during treatment, including evaluation of erectile function, libido, and ejaculation quality at follow-up visits, with consideration of using validated questionnaires like the Arizona Sexual Experience Scale 1, 4, 2
Risk factors for post-finasteride syndrome may include a history of depression, pre-existing sexual dysfunction, and infertility, although the evidence is limited 4

Gynecomastia, or breast enlargement, occurs in approximately 2.2% of patients on long-term finasteride treatment, according to the Endocrine Society 1
Breast tenderness is reported in 0.7% of patients on long-term treatment 1

Patient counseling is essential, and thorough discussion of potential risks, including the possibility of persistent sexual side effects, is recommended before initiating therapy, as suggested by the American Urological Association guidelines 1, 2
Consider stopping finasteride if sexual side effects develop and persist, or if post-finasteride syndrome (PFS) occurs, characterized by a constellation of sexual, physical, and psychological symptoms that may persist after discontinuation 1
Early discontinuation of finasteride if persistent side effects occur may reduce the risk of permanent effects, and consideration of alternatives for patients who develop sexual dysfunction is recommended 1
Clinicians should consider alternatives to finasteride for patients with pre-existing sexual dysfunction, and discontinue the drug at the first sign of problems to reduce the risk of persistent effects, as recommended by the American Urological Association 4

The American Academy of Family Physicians suggests evaluating erectile function, libido, and ejaculation quality at each follow-up, and considering using validated questionnaires like the Arizona Sexual Experience Scale, and screening for symptoms of depression or anxiety 1
The FDA has added a warning about potential persistent sexual side effects to the drug label, emphasizing the importance of patient counseling and monitoring 5