A form of the contraceptive coil could help protect women at high risk of womb cancer, researchers believe.
The four-year POET trial aims to test the theory in women with Lynch syndrome, who have a 60% chance of developing the disease.
The coil releases a hormone which reduces the thickness of the womb wall, potentially halting the growth of abnormal cells.
Womb cancer is the fifth most common in UK women, with 6,000 cases a year.
The implanted coil remains a popular contraceptive device, and the arrival of versions such as the Mirena IUS, that also contains the hormone progestagen has diminished further the likelihood of an unwanted pregnancy.
One in 50 UK women will develop womb cancer, although there is already some evidence that Mirena IUS can cut this risk.
Lynch syndrome is an inherited disorder which raises the chance of a number of cancers, most notably bowel cancer and womb.
While most women who develop womb cancer do so after the menopause, it tends to appear earlier in life in Lynch syndrome patients, making its key symptom, irregular bleeding, harder to detect.
Most are offered a hysterectomy to protect them, and the idea behind the trial is to see whether the coil and hormone could help them avoid this.
It is hoped that 220 women will be recruited at centres in Glasgow and London, half of whom will simply be monitored, while the other half also receive the coil.
It is thought that the hormone stops the thickening of womb tissue, preventing prevent the unchecked division of cells in the lining which can lead to a cancer.
Dr Victoria Murday, from the Yorkhill Hospital in Glasgow, said: "We are uncertain how effective it is to screen for endometrial cancer in women at increased risk of the disease, so prevention is the key.
"Earlier research has provided evidence that this coil may reduce the risk of endometrial cancer , and we hope that this study can show that it has this effect for women at high risk, who might otherwise opt for hysterectomy."
Cancer Research UK is funding the trial, and its spokesman, Kate Law, said: "It is vital that we continue to research prevention techniques like this one.
"We need to learn if we can offer those women at high risk of womb cancer more options to help prevent the disease."