Humans

5-ARI use is tied to lower laryngeal cancer risk in men

In a Swedish cohort, 5-ARI users had a 17% lower risk of laryngeal or hypopharyngeal squamous cell carcinoma than nonusers (adjusted hazard ratio, 0.83).

JAMA Otolaryngology-- Head & Neck Surgery

In a cohort study of Swedish men, researchers investigated whether 5α-reductase inhibitors (5-ARIs) were associated with a lower risk of laryngeal and hypopharyngeal squamous cell carcinoma. 5-ARIs inhibit the conversion of testosterone to dihydrotestosterone. The study analyzed 253,010 men who received at least two 5-ARI dispensations within two years and 1,265,050 age- and date-matched nonusers, with a median participant age of 74 years. Over a median follow-up of 5.8 years for users and 4.7 years for nonusers, 215 users (0.1%) and 1,131 nonusers (0.1%) developed these cancers. After adjusting for tobacco smoking, alcohol overconsumption, hypertension, hyperlipidemia, and diabetes, 5-ARI use was associated with a 17% lower cancer risk (adjusted hazard ratio, 0.83; 95% CI, 0.72-0.96).

Why it matters

These squamous cell carcinomas predominantly affect men. The results support a possible partial role for testosterone in driving this sex disparity and tumor development.

Caveats

Because this was an observational study, it cannot establish a causal relationship. Residual confounding from unmeasured factors may also persist despite adjustments for smoking and alcohol use.

The paper

Testosterone Inhibition and Risk of Laryngeal and Hypopharyngeal Squamous Cell Carcinoma in Men