Can your reproductive history affect your survival of breast cancer?

The authors aimed to determine whether or not there was a link between reproductive characteristics of women and their potential risk of cancer recurrence (the cancer returns) and survival.

Breast cancer survival is influenced by a range of risk factors. A woman’s reproductive history can often be associated, as giving birth will cause women to experience hormonal changes.  Some types of tumors can grow in response to hormones such as estrogen and progesterone and thus, hormone changes. 

The overall effects of a woman’s reproductive history on breast cancer survival, however, have not been well studied.

The aims of this study were to assess the possible link between a woman’s reproductive history (number of children, time since last child birth, etc.) and her risk of cancer recurrence and overall survival.

A total of 3430 patients with breast cancer were analyzed. Of these women, 69.8% were positive for hormone receptor breast cancer (HR+). 23.2% showed an overexpression of human epidermal growth factor receptor 2 (HER2+ breast cancer, dependent on HER2 for growth).

Compared to women who last gave birth 20 or more years ago, women who last gave birth less than 5 years ago had a 67% greater risk of a faster recurrence. Women with 4 or more children had a 58% greater risk of a faster time to recurrence compared to those who had 2 or less. Patients who started menstruating at an older age were 10% more likely to have a short overall survival time (time from treatment until death from any cause) compared to patients who began at a younger age.

Every one year of exposure to natural estrogen (due to earlier start of menstruation or later menopause) increased the possibility of a longer DFS by 3%. 

Patients with HR+HER2+ breast cancer were 44% more likely to survive those with HR- tumors. Those with HR- tumors were more than twice as likely to develop cancer recurrence as those with HR+.

The authors concluded that prolonged estrogen exposure (length of time between having children) among women with HR+HER2+ breast cancer was associated with improved chances of survival.