Invasive Breast Cancer Risk Highest Following Childbirth
Premenopausal women diagnosed less than five years after childbirth more likely to have invasive disease
FRIDAY, May 2 (HealthDay News) -- Women who develop premenopausal breast cancer less than five years after the birth of their last child are more likely to be diagnosed with later-stage disease than women who develop breast cancer later, researchers report in the May issue of Obstetrics & Gynecology.
Linda Dodds, Ph.D., from Dalhousie University in Halifax, Nova Scotia, Canada, and colleagues investigated the association between time since childbirth and the prognosis of premenopausal breast cancer (at younger than 50 years old) in 123,323 women in Nova Scotia who delivered an infant from 1980-2001.
The researchers found that 716 women were diagnosed with invasive breast cancer. Women were more likely to be diagnosed with later-stage disease if there was less than five years between their last delivery and diagnosis, with an adjusted hazard ratio of 2.1 for less than two years and a hazard ratio of 1.6 for two to four years. Compared with women with at least five years between delivery and diagnosis, the researchers estimated that there would be one excess death for every 13 women with an interval of less than two years.
"A time interval of less than two years (and two to four years) between childbirth and breast cancer diagnosis worsens the prognosis in a dose-response fashion," Dodds and colleagues conclude.