Metformin may lower nasopharyngeal cancer risk

Takeaway

• This study suggests that metformin may significantly decrease the risk for nasopharyngeal cancer (NPC), especially when it has been used for >2 years.

Why this matters

• Metformin is associated with a reduction of risk for various types of cancers, however, its protective effect against NPC is unknown.

Study design

• Cohort study of 30,972 patients (metformin ever-users, n=15,486; never-users, n=15,486) with type 2 diabetes mellitus from the reimbursement database of Taiwan's National Health Insurance between 1999 and 2005.
• Funding: Ministry of Science and Technology of Taiwan.

Key results

• Median follow-up duration was 5.5 years for never-users and 5.4 years for ever-users; 1105 ever-users and 1496 never-users died during follow-up.
• Incidence of NPC was 106.04 per 100,000 person-years among never-users and 33.41 among ever-users.
• Risk for NPC was significantly lower among metformin ever-users vs never-users (HR, 0.312; P<.0001).

Limitations

• Risk for bias.
• Lack of data for confounders.