Study: Lactation Drug Cabergoline May Reduce Postpartum Cancer Risk
Research published in Cancer Discovery indicates that a medication used during lactation may lower the likelihood of developing breast cancer for mothers following childbirth, as revealed by a global group of scientists.
- Cabergoline, a medication typically used to suppress milk production, was associated with an approximately 70 percent reduction in subsequent breast cancer risk in a health record analysis of over 150,000 women from Spain and Norway.
- When investigators administered a single dose of cabergoline to mice possessing BRCA1 and TP53 mutations linked to severe breast cancer varieties, the frequency of tumors dropped by roughly half.
- Researchers have secured funding from the Gray Foundation to launch a multinational clinical trial recruiting women with BRCA1 mutations through high-risk clinics.
Health Record Analysis Across Spain and Norway Involves 150,000 Women
The study examined health records from Spain and Norway to track outcomes for more than 150,000 women with information on cabergoline use. Patients who took the medication to suppress milk production after pregnancy loss or when breastfeeding was not possible showed a significantly lower incidence of breast cancer in the years following, compared to those who did not receive the drug.
This epidemiological observation aligned directly with experimental results in animal models. Scientists noted that tumor formation rates decreased by approximately 50 percent after administering a single dose of cabergoline to mice harboring BRCA1 and TP53 mutations linked to aggressive breast cancer types.
Breast cancer is the leading cause of cancer-related death among younger women, and the majority of these cancers occur during the years after pregnancy,
said study co-lead Dr. Christopher Maxwell, professor in UBC’s faculty of medicine and investigator at the BC Children’s Hospital Research Institute, as reported by the study. This is particularly true for women at high risk of breast cancer. But our findings suggest there may be an opportunity to reduce that risk with an existing drug by helping the breast complete a natural process that happens after breastfeeding ends.
Targeting Breast Involution After Weaning
Following the cessation of breastfeeding, the breast undergoes a major biological clean-up process known as involution. Dr. Maxwell compared this transition to a fruit tree shedding what it no longer needs after the growing season to prepare for the next phase. During pregnancy, hormone levels rise and milk-producing structures branch out, but once nursing stops, those cells are cleared away.
Researchers discovered that this clean-up process can remain incomplete in experimental mice, leaving behind cells that may become cancerous. Cabergoline appears to assist in completing that transition by accelerating the post-weaning process. In mouse studies, the medication reduced potentially precancerous tissue, shrunk the ductal area, curtailed excessive cell growth, and boosted immune cells responsible for clearing damaged cells.
With one in eight women in Canada developing breast cancer in their lifetime, the study authors emphasize that new prevention strategies are urgently required. We think the period after breastfeeding is an important window for prevention,
said study co-lead Dr. Jesús Perez-Losada, a researcher at the Cancer Research Center, a joint institute of the Spanish National Research Council and the University of Salamanca, as detailed by the study. There is a unique opportunity to target involution, the natural process that begins after weaning. This is not about changing a woman’s breastfeeding plans; any preventive intervention would be considered only after breastfeeding has ended.
Gray Foundation Funds Human Trials for Cabergoline
The next phase of investigation involves testing cabergoline in human clinical trials to verify whether the protective effects observed in mice translate to patients. Funding for this multi-country trial has been secured through the Gray Foundation. High-risk clinics will recruit women with a BRCA1 mutation, who will choose their duration of breastfeeding. After weaning, participants will be randomly assigned to receive either cabergoline or a placebo while researchers monitor biological markers associated with future breast cancer risk.
Current preventative options for women at high risk often involve hormone therapy or surgery, both of which carry substantial physical and emotional side effects. Because cabergoline is already approved by regulatory bodies such as Health Canada and the European Medicines Agency, successful clinical trial results could provide a more tolerable option for breast cancer prevention.
Financial support for the research was provided by the Canadian Institutes of Health Research, the Canadian Cancer Society, the Terry Fox Research Institute, and Spain’s Ministerio de Ciencia e Innovación / Agencia Estatal de Investigación, alongside additional funding agencies in the United Kingdom and the United States.