More direct contact with tumor cells
In Dr. Saura’s opinion, in Spain, just like taking a small blood sample from newborns in a heel-prick test to rule out metabolic diseases, milk samples could be taken from women who give birth to rule out or diagnose breast cancer.
As to the potential advantages that breast milk liquid biopsy could have over similar techniques like blood liquid biopsy, Dr. Vivancos pointed to the results of her study: “We have seen that breast milk liquid biopsy was positive for the presence of circulating tumor DNA in 87% of cases, whereas blood only revealed the presence of this marker in 8% of cases. This difference indicates that breast milk is a biofluid that is in more direct contact with tumor cells and therefore will be more informative in earlier stages.”
Dr. Saura explained that the data does not lie when it comes to these tumors in pregnant or postpartum women. “In general, they tend to have a worse prognosis because, in most cases, they are diagnosed in advanced stages. Furthermore, it is typically assumed that the physiological changes in the breasts during gestation and lactation, which are considered to be normal, may hide a developing tumor. The fact is that postpartum breast cancer, understood to be the 10 years after delivery, accounts for 40%-45% of breast cancer cases diagnosed before age 45.”
The researchers plan to continue this project. “Our next step to confirm the usefulness of breast milk as a new tool for liquid biopsy for early detection of breast cancer during the postpartum period is to perform this noninvasive test in thousands of women,” said Dr. Saura.
Goal: Standardize the test as a screening method
“Based on the results we’ve published, we’re starting a study aimed at collecting breast milk samples from 5,000 healthy women around the world who became pregnant at age 40 or older, or who got pregnant at any age and carry mutations that increase their risk of breast cancer,” Dr. Saura added.
When asked when they expect to have preliminary results from this new study, Dr. Saura stated that it’s not yet possible to say exactly when. “We’re still waiting for funding to continue this project, but we continue performing analyses on a case-by-case basis. Of course, if we detect any abnormalities in these women, we will follow the established protocol to confirm diagnosis and start treatment if necessary.”
When asked whether it is reasonable to expect breast milk liquid biopsy to become normalized as a screening method for women of childbearing age who have a history or risk factors for developing breast cancer, Dr. Vivancos said, “That’s the scenario we see in the future and what we wish to contribute toward by providing scientific evidence to make it a reality.”
“For now, our goal is to validate whether circulating tumor DNA can be detected by breast milk liquid biopsy even before breast cancer can be diagnosed using conventional imaging techniques. If we can validate these preliminary results, we will be able to detect breast cancer early using a noninvasive test like breast milk liquid biopsy,” explained Saura.
Lastly, and in view of the issues that are still unresolved when it comes to the detection and treatment of breast cancer during pregnancy, Dr. Saura highlighted the emotional impact that a diagnosis of pregnancy-related cancer has on women and on those close to them. “But the first thing they need to know is that diagnosis is not necessarily synonymous with termination of the pregnancy. On the contrary, this tumor can be treated during pregnancy, since surgery can be performed at any time, and chemotherapy can be started in the second trimester. Proof of this is the 72 children who have been born under these circumstances in the past 20 years at the Vall d’Hebrón University Hospital. This hospital is a pioneer in Spain thanks to its multidisciplinary program for education and specific follow-up with women who have been diagnosed with a breast tumor during pregnancy.”
Dr. Saura and Dr. Vivancos reported no relevant financial relationships.
This article was translated from the Medscape Spanish edition. A version of this article appeared on Medscape.com.