Vancouver's clinical trials test lactation drug to prevent postpartum breast cancer
A drug that stops milk production could cut breast cancer risk by 70%, and UBC researchers are testing it in women with BRCA1 mutations.
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A drug used to stop milk production after pregnancy loss could significantly lower the risk of postpartum breast cancer, and Vancouver researchers are launching clinical trials to test it.
Cabergoline cut breast cancer risk by about 70 per cent in a study of more than 150,000 women in Spain and Norway, published last week in Cancer Discovery. Trials will begin in Vancouver, Toronto, the U.K., and Spain, with researchers hoping to test the first patient sometime next year.
"Younger adult females have almost twice as much cancer as younger adult males, and that's principally due to breast cancer," said Dr. Chris Maxwell, a UBC professor and study co-author at B.C. Children's Hospital Research Institute.
The drug works by blocking prolactin, a hormone that triggers milk production. When women stop breastfeeding, the drug helps clear out milk-producing cells in the breast, potentially preventing tumours from developing during the vulnerable postpartum period—a time when breast cancer often carries a poor prognosis and requires urgent chemotherapy.
Trials will recruit women with BRCA1 mutations, who have a 70 to 80 per cent lifetime chance of developing breast cancer. Participants will choose their breastfeeding duration, then be randomly assigned to cabergoline or placebo after lactation ends. Researchers will monitor biological markers linked to future breast cancer risk.
If successful, the drug could offer an alternative to double mastectomy for some high-risk women. The trials are funded by the Canadian Institutes of Health Research, the Canadian Cancer Society, the Terry Fox Research Institute, and agencies in Spain, the U.K., and the U.S.
The facts
What drug are Vancouver researchers testing for breast cancer prevention?
Cabergoline, a drug that stops milk production after pregnancy loss. It works by blocking prolactin, a hormone that triggers milk production, and helps clear out milk-producing cells in the breast.
How much did cabergoline reduce breast cancer risk in previous research?
A study of more than 150,000 women in Spain and Norway found cabergoline cut breast cancer risk by about 70 per cent.
Which women are eligible for the clinical trials?
Women with BRCA1 mutations, who have a 70 to 80 per cent lifetime chance of developing breast cancer.
Where will the clinical trials take place?
Vancouver, Toronto, the U.K., and Spain.
