In 2005, an observational study of almost 12,000 people with diabetes hinted that the type 2 diabetes drug metformin might also work against cancer, suggesting a 23% lower rate of cancer among those who had taken it. Since then, thousands of papers have explored this idea, but no gold-standard clinical evidence has emerged to support the theories.
Recent trials for two types of cancer have reported no benefits from metformin. Early observational studies might have exaggerated metformin’s potential because of ‘immortal time bias,’ a phenomenon where individuals who died from cancer were not able to try metformin, creating an illusion of a survival benefit.
Despite initial excitement, metformin has not lived up to its promise as a cancer treatment. Researchers have conducted numerous studies on lab cells, animals, and humans, but the results have been inconsistent. Some studies suggested that metformin could slow the growth of various cancer cells and enhance their sensitivity to chemotherapy drugs, but these findings haven’t translated into successful clinical trials.
The lack of conclusive evidence has led many experts to advise against using metformin as a cancer treatment. For instance, Pamela Goodwin, an epidemiologist and medical oncologist, often receives inquiries from patients about whether they should take metformin for cancer treatment, to which she advises against it due to the lack of definitive proof.
While metformin remains a leading treatment for type 2 diabetes, its potential as a cancer therapy has not materialized. More research is required to understand the mechanisms by which metformin might affect cancer cells and determine whether it could be repurposed for cancer prevention or treatment.
In conclusion, metformin’s journey from a diabetes drug to a potential cancer treatment has been one of hope and disappointment. Although initial studies were promising, the lack of clinical evidence has dashed the hopes of researchers and patients alike. The search for effective cancer treatments continues, with metformin’s story serving as a reminder of the complexities and challenges of drug repurposing.
