Portrait of female cancer survivor, smiling in pink.Solar panels against a blue sky with clouds.

The Hidden Impact of Menstrual Cycles in Cancer Research

February 4, 2025

Author:

Danika Kelly

‘I study cancer, I don’t need menstrual cycle data.’

This common refrain in medical research reflects a critical blind spot in our approach to understanding disease and treatment efficacy.

While women have gained representation in drug research for female-specific conditions like breast cancer, they remain underrepresented in broader medical studies. The reasons often cited include:

  • The complexity of menstrual cycle hormonal fluctuations
  • Concerns about potential harm to reproductive cells
  • A preference for "simpler" male research models with less hormonal variation

This simplified approach creates a dangerous paradox: by avoiding the complexity of female biology, we limit our understanding of how drugs actually work in women's bodies. Mere inclusion of female subjects without accounting for biological rhythms and hormonal variations isn't true representation - it's an oversight that can mask important differences in treatment response and effectiveness.

As one researcher aptly noted, “Testing female subjects while ignoring hormonal variability is like evaluating a fish by its ability to climb a tree." We need research methodologies that acknowledge and account for the fundamental realities of female biology, including hormonal cycles and their potential impact on treatment outcomes.

In cancer research specifically, understanding these biological rhythms could be crucial for optimizing treatment timing and effectiveness. The scientific community must move beyond simply including women in trials to truly studying how female biology influences disease progression and treatment response.

For an in-depth exploration of this topic, see VIB's recent analysis Does the menstrual cycle influence the effect of chemotherapy?