Open Trial Seeks Women on Hormonal Therapy Who Want to Become Pregnant

POSITIVE study will look at effects of taking a treatment break for pregnancy
Featured Clinical Trials
November 8, 2017
Robin Warshaw, contributing writer
Reviewed By: 
Kathy D. Miller, MD

The “Pregnancy Outcomeinfo-icon and Safety of Interrupting Therapyinfo-icon for Women With Endocrineinfo-icon Responsive Breast Cancer,” or POSITIVE, study, is an international clinical trialinfo-icon looking at whether temporarily stopping hormonal therapyinfo-icon, such as tamoxifeninfo-icon, to allow time for pregnancy increases the risk of breast cancer recurrenceinfo-icon.

The study needs participants who want to become pregnant and have been on hormonal treatment for no more than 2.5 years.


At one time, doctors advised women to avoid pregnancy after a breast cancer diagnosisinfo-icon. It was thought the higher estrogeninfo-icon levels that come with pregnancy would cause breast cancer to return.

Recent studies suggest that pregnancy after early-stage breast cancerinfo-icon does not increase risk of recurrence, even in women with estrogen receptor-positiveinfo-icon disease.

Many women have not had a child or finished having children before receiving a breast cancer diagnosis. If their breast cancer is sensitive to estrogen or progesteroneinfo-icon, they are likely to take hormonal therapy to help prevent the cancer from coming back. That treatment can affect the ability to become pregnant because it interferes with the function of the ovaries and ovulationinfo-icon.

Hormonal therapy also can cause harm to a developing fetus, so women can’t take the medicineinfo-icon while they are pregnant. But waiting 5 to 10 years for some women could mean entering natural menopauseinfo-icon because of age before treatment ends.

Researchers want to find out if stopping hormonal therapy temporarily to allow a woman to carry out a pregnancy is safe and does not increase recurrence risk.


The POSITIVE study is mainly interested in how long women live without a return of stageinfo-icon I or higher breast cancer after temporarily stopping hormonal therapy to attempt a pregnancy.

The trial will also measure

  • return of menstrual periods and timing
  • pregnancy rate and results, such as full-term births, caesarean sections or miscarriages
  • details of newborn’s health such as low birth weight
  • breastfeeding patterns
  • use of fertilityinfo-icon methods to achieve pregnancy
  • the length of time between joining the study and cancer spreading to another area of the body, outside the breast.


The study is seeking 500 participants. It is being run by the International Breast Cancer Study Group at 150 locations in North America, Europe and Asia.

All women who enroll in the POSITIVE trial will wait 3 months after stopping hormonal treatment before trying to get pregnant. This “wash-out” period allows time for the hormonal medicine to leave the body.

Participants will have no hormonal therapy for up to 2 years. This provides time for pregnancy and delivery, breastfeeding, and unsuccessful attempts to become pregnant. Hormonal therapy will begin again after the 2-year interruption and continue for the full course of treatment.


To participate, you must be between 18 and 42 years old. You also must

  • have been diagnosed with early-stage, hormone receptorinfo-icon-positive breast cancer and completed active treatment
  • have been taking hormonal therapy for at least 18 months but not more than 30 months
  • want to become pregnant
  • have been premenopausalinfo-icon at breast cancer diagnosis
  • be available for follow-up

Participants with BRCA mutations are eligible to enroll.

You will not be able to participate if you:

Talk with your doctor if you are interested in taking part in the POSITIVE trial. You can find more information on who is eligible for the study, plus contact details and locations, in the trial listing on

You must have Javascript enabled to use this form.
Additional Related Topics 
Hormonal Therapy