Researchers explore effect of menstrual cycle on breast cancer treatment
A team of Belgian and Dutch researchers has found that phases of the menstrual cycle may influence the effectiveness of chemotherapy in breast cancer. The impact of the cycle on the body is greater than previously thought, Flemish research institute VIB reports on Thursday.
“Scientists are only now beginning to realise this,” says Sabine Linn of the Netherlands Cancer Institute said in a press release. “It is becoming increasingly clear that there is a blind spot in drug research.”
The team’s findings highlight the importance of further research on the menstrual cycle, the effects of drugs in women versus men, and women-specific research in general.
“We were studying how chemotherapy can alter cancer cells, making them more resistant to the therapy,” said Jacco van Rheenen, a researcher at the Netherlands Cancer Institute and Oncode Institute. “But we saw that change in some mice and not in others. And we know that women with breast cancer respond variably to chemotherapy, but not why that is.”
Sensitive phase
The researchers suggested that the estrus cycle, the mouse version of the menstrual cycle, may have played a role and they have begun mapping it in more detail.
Meanwhile, other research by Van Rheenen and Colinda Scheele of VIB and KU Leuven shows that the menstrual cycle influences the behaviour of breast cells and cancer cells.
"It is becoming increasingly clear that there is a blind spot in drug research"
“We saw there was a sensitive phase of the cycle where more cancer cells were killed by the chemotherapy,” said Scheele. “That sensitivity to the chemotherapy remained even after the cycle stopped because of treatment. So the moment of giving the first dose was important.”
Monitoring links
The degree of tissue defence varied by phase, as did the permeability of blood vessels, through which the chemotherapy enters the tissue. The researchers are now setting up a study of women undergoing chemotherapy, which will monitor possible links to their menstrual cycle.
It is possible that some drugs work better in one phase of the cycle than another, the researchers say. Van Rheenen: “So much changes in a body under the influence of hormones. Just the fluctuations in body temperature: think what they do to your blood circulation.” The immune system is also affected as the cycle prepares the woman for possible pregnancy.
"More research in this area will ultimately lead to better health for the female half of the world's population"
Women have historically been underrepresented in drug research, in part due to the complexity of the menstrual cycle, where fluctuations in hormone levels can affect outcomes. Research therefore still concentrates on male subjects and animals, meaning there is much less knowledge of how drugs work in women.
Scheele: “More research in this area will ultimately lead to better health for the female half of the world's population.”
#FlandersNewsService | © Luxembourg station in Brussels is lit up in pink to mark the start of International Breast Cancer Month in October 2024 © BELGA PHOTO HATIM KAGHAT
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