A study looking at giving hormone treatment to prevent womb cancer in obese women (PROTEC1)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Womb (uterine or endometrial) cancer





This study is looking at whether giving hormone treatment to obese women reduces their risk of developing womb cancer.

More about this trial

Women who are very overweight have an increased risk of developing womb cancer. Before womb cancer develops there can be changes in the lining of the womb (the endometrium).

In this study, doctors want to see if giving a type of hormone called progesterone through the Mirena intrauterine system Open a glossary item (Mirena IUS) will prevent these changes. And so reduce the chances of cancer developing. They also wants to find out if this treatment is acceptable to women and how much they know about their own personal risk of developing womb cancer

Who can enter

You may be able to join this study if all of the following apply.

  • You have a body mass index Open a glossary item (BMI) of 40 or higher
  • Your most recent cervical smear Open a glossary item was normal
  • You are not actively trying to lose weight
  • You are aged at least 18 years old

If you are interested in taking part in the study the researchers will take some blood and also a sample of the lining of your womb (this is similar to having a cervical smear test). Your blood test results and the sample of your womb lining must be normal for you to continue in the study.

You cannot join this study if any of these apply. You

  • Have had your womb removed (a hysterectomy)
  • Have had a intrauterine system or device (coil) in the last 6 months
  • Have had treatment to the lining of your womb for heavy periods or abnormal bleeding (endometrial ablation)
  • Have breast cancer
  • Have any problems (anomalies) with your womb
  • Have pelvic inflammatory disease or genital actinomycosis
  • Have immune deficiency Open a glossary item meaning you are more likely to get infections
  • Are not able to have the Mirena IUS for any reason (your doctors can advise you about this)
  • Are pregnant or breastfeeding

Trial design

This study needs 40 women to take part.

At your 1st visit

  • The research team will ask you some questions about your health, any medications you take and your lifestyle
  • Measure your height, weight, waist and hips
  • Check your blood pressure
  • Take some blood samples
  • Take a sample of the lining of your womb. This is very similar to having a cervical smear test.

If the results from the blood tests and the womb lining sample are normal then the team will see you again in 3 months. At this 2nd visit you will have more blood tests, another sample of the womb lining taken and a Mirena IUS inserted.

The Mirena IUS is a T shaped plastic device. It releases a hormone called levonorgestrel which is a type of progesterone.

After this appointment the researchers will telephone every 6 weeks to see how you are.

6 to 9 months after the Mirena IUS has been inserted you have a third appointment with the same blood tests and womb lining sample taken as before.

If the tests you have during the study show any abnormalities the team will discuss appropriate treatment with you.

At every visit you need to complete a questionnaire about your health and well being. You can do at this at the clinic or at home and then return it to the team. You will also be asked about your periods and to complete a blood loss chart the next time you have a period. The team will explain what is involved in completing this.

Hospital visits

During the study you visit the hospital up to 3 times. The first visit will take about an hour and the next 2 visits will be slightly shorter.

Side effects

Having you womb lining sampled and a Mirena IUS inserted can be uncomfortable and some women find it painful. The Mirena IUS can

  • Reduce the length of your period or the amount of bleeding you have
  • Cause bleeding between periods or stop your period

There are some rare side effects associated with having the Mirena IUS inserted and the researchers will discuss this with you at the start of the study.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Dr Emma Crosbie

Supported by

Central Manchester University Hospitals NHS Foundation Trust
NIHR Clinical Research Network: Cancer
University of Manchester

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Cara took part in a clinical trial

A picture of Cara

"I am glad that taking part in a trial might help others on their own cancer journey.”

Last reviewed:

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