Katharina Buczek
The first group included patients who were diagnosed five years of childbirth. The second group of patients was diagnosed between five and ten years post-childbirth, and the third group received diagnoses ten or more years later.
The researchers then found that the risk of metastasis increased by fifty percent among women who were diagnosed with breast cancer within five years of childbirth.
And interestingly, this increased risk was persistent regardless of estrogen receptor status or tumor stage.
These are both two factors currently used to assess how aggressive a patient’s cancer will be and what courses of treatment are optimal.
Additionally, even though ER-negative tumors– or breast cancers that do not have estrogen receptors– are typically regarded as more dangerous than ER-positive tumors, this was not a significant factor in the study.
Instead, the most significant risk factor for breast cancer metastasis progression was a diagnosis within five years of giving birth.
Finally, the researchers made two critical findings regarding the causes of this increased risk. The first pertains to lactation, or rather, the end of it.
After women finish nursing, a majority of the milk-secreting cells undergo a process known as involution– or programmed cell death.
This process is similar to wound healing but, among mouse models, proved to foster an environment that promotes tumor growth.
The researchers then confirmed this mouse model finding among the study participants by collecting tissue samples.
The mouse model studies also revealed that as a woman’s liver tries to recover from the stress of pregnancy, it becomes a safe haven for cancer cells to grow.
