Diabetes treatment may also provide protection against endometrial cancer

Endometrial cancer is the most common malignancy of the female genital tract and the fourth most common cancer in women in the UK and the US. Up to a third of PCOS women also have endometrial hyperplasia which, in turn predisposes these women to endometrial cancer. PCOS affects 5%-10% of women of reproductive age, where metformin ameliorates insulin resistance and hyperinsulinemia in these women, but also long-term use of metformin improves ovulation and menstrual cycle regularity.

Recent research has found that metformin has anti-cancer properties, e.g., in breast cancer. Given that insulin resistant states, e.g. obesity, diabetes and PCOS are more at risk of developing endometrial cancer, the Warwick researchers studied the effects of metformin treatment on endometrial cancer cells. The researchers used serum from control and PCOS (before and after metformin treatment) subjects and carried out basic scientific experiments on endometrial cancer cells. The experiments revealed a decrease in endometrial cancer cell invasiveness in sera from metformin treated PCOS women.

The researchers found that serum samples from PCOS women who had completed the 6 month course of metformin the rate of spread of endometrial cancer cells was around 25% lower than in the serum samples from PCOS women who had not started that treatment.

The principal investigators, Dr Harpal Randeva and Dr Bee K Tan, at Warwick Medical School said: "We are very excited about our findings, which reveal the significant impact of metformin therapy use on human endometrial cancer cells. However, it is prudent that further research to explore if metformin would actually be beneficial clinically as adjuvant therapy in endometrial cancer; this would need to be addressed through a randomized controlled trial."