Parity linked to rare cancer
THE risk of developing the uncommon, but aggressive, triple-negative breast cancer rises with parity, a study suggests.
Data from the Women’s Health Initiative involving more than 155,000 postmenopausal women found nulliparity was associated with an increased risk of oestrogen receptor-positive breast cancer but a 40% decreased risk of cancer which was oestrogen receptor-, progesterone receptor- and HER2- negative.
Among parous women, having three births or more increased the risk of triple-negative disease by 46% compared with having one birth.
No association was found between triple-negative breast cancer and pregnancy loss, breastfeeding, or age of menarche and menopause.
The biological mechanisms underlying the observations were uncertain, the researchers said.
It remained important to identify predisposing factors to the development of triple-negative breast cancer given the poor prognosis associated with this subtype